Avoid recomputing fuzzy match scores (#13700)

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# Description
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This PR makes it so that when using fuzzy matching, the score isn't
recomputed when sorting. Instead, filtering and sorting suggestions is
handled by a new `NuMatcher` struct. This struct accepts suggestions
and, if they match the user's typed text, stores those suggestions
(along with their scores and values). At the end, it returns a sorted
list of suggestions.

This probably won't have a noticeable impact on performance, but it
might be helpful if we start using Nucleo in the future.

Minor change: Makes `find_commands_by_predicate` in `StateWorkingSet`
and `EngineState` take `FnMut` rather than `Fn` for the predicate.

# User-Facing Changes
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helps us keep track of breaking changes. -->

When using case-insensitive matching, if you have two matches `FOO` and
`abc`, `abc` will be shown before `FOO` rather than the other way
around. I think this way makes more sense than the current behavior.
When I brought this up on Discord, WindSoilder did say it would make
sense to show uppercase matches first if the user typed, say, `F`.
However, that would be a lot more complicated to implement.

# Tests + Formatting
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Added a test for the changes in
https://github.com/nushell/nushell/pull/13302.

# After Submitting
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crates/nu-cli/src/completions/command_completions.rs

@@ -1,5 +1,7 @@
+use std::collections::HashMap;
+
 use crate::{
-    completions::{Completer, CompletionOptions, MatchAlgorithm},
+    completions::{Completer, CompletionOptions},
     SuggestionKind,
 };
 use nu_parser::FlatShape;
@@ -9,7 +11,7 @@ use nu_protocol::{
 };
 use reedline::Suggestion;
 
-use super::{completion_common::sort_suggestions, SemanticSuggestion};
+use super::{completion_options::NuMatcher, SemanticSuggestion};
 
 pub struct CommandCompletion {
     flattened: Vec<(Span, FlatShape)>,
@@ -33,10 +35,11 @@ impl CommandCompletion {
     fn external_command_completion(
         &self,
         working_set: &StateWorkingSet,
-        prefix: &str,
+        sugg_span: reedline::Span,
-        match_algorithm: MatchAlgorithm,
+        matched_internal: impl Fn(&str) -> bool,
-    ) -> Vec<String> {
+        matcher: &mut NuMatcher<String>,
-        let mut executables = vec![];
+    ) -> HashMap<String, SemanticSuggestion> {
+        let mut suggs = HashMap::new();
 
         // os agnostic way to get the PATH env var
         let paths = working_set.permanent_state.get_path_env_var();
@@ -54,24 +57,38 @@ impl CommandCompletion {
                                 .completions
                                 .external
                                 .max_results
-                                > executables.len() as i64
+                                <= suggs.len() as i64
-                                && !executables.contains(
-                                    &item
-                                        .path()
-                                        .file_name()
-                                        .map(|x| x.to_string_lossy().to_string())
-                                        .unwrap_or_default(),
-                                )
-                                && matches!(
-                                    item.path().file_name().map(|x| match_algorithm
-                                        .matches_str(&x.to_string_lossy(), prefix)),
-                                    Some(true)
-                                )
-                                && is_executable::is_executable(item.path())
                             {
-                                if let Ok(name) = item.file_name().into_string() {
+                                break;
-                                    executables.push(name);
                             }
+                            let Ok(name) = item.file_name().into_string() else {
+                                continue;
+                            };
+                            let value = if matched_internal(&name) {
+                                format!("^{}", name)
+                            } else {
+                                name.clone()
+                            };
+                            if suggs.contains_key(&value) {
+                                continue;
+                            }
+                            if matcher.matches(&name) && is_executable::is_executable(item.path()) {
+                                // If there's an internal command with the same name, adds ^cmd to the
+                                // matcher so that both the internal and external command are included
+                                matcher.add(&name, value.clone());
+                                suggs.insert(
+                                    value.clone(),
+                                    SemanticSuggestion {
+                                        suggestion: Suggestion {
+                                            value,
+                                            span: sugg_span,
+                                            append_whitespace: true,
+                                            ..Default::default()
+                                        },
+                                        // TODO: is there a way to create a test?
+                                        kind: None,
+                                    },
+                                );
                             }
                         }
                     }
@@ -79,7 +96,7 @@ impl CommandCompletion {
             }
         }
 
-        executables
+        suggs
     }
 
     fn complete_commands(
@@ -88,69 +105,60 @@ impl CommandCompletion {
         span: Span,
         offset: usize,
         find_externals: bool,
-        match_algorithm: MatchAlgorithm,
+        options: &CompletionOptions,
     ) -> Vec<SemanticSuggestion> {
         let partial = working_set.get_span_contents(span);
+        let mut matcher = NuMatcher::new(String::from_utf8_lossy(partial), options.clone());
 
-        let filter_predicate = |command: &[u8]| match_algorithm.matches_u8(command, partial);
+        let sugg_span = reedline::Span::new(span.start - offset, span.end - offset);
 
-        let mut results = working_set
+        let mut internal_suggs = HashMap::new();
-            .find_commands_by_predicate(filter_predicate, true)
+        let filtered_commands = working_set.find_commands_by_predicate(
-            .into_iter()
+            |name| {
-            .map(move |x| SemanticSuggestion {
+                let name = String::from_utf8_lossy(name);
+                matcher.add(&name, name.to_string())
+            },
+            true,
+        );
+        for (name, description, typ) in filtered_commands {
+            let name = String::from_utf8_lossy(&name);
+            internal_suggs.insert(
+                name.to_string(),
+                SemanticSuggestion {
                     suggestion: Suggestion {
-                    value: String::from_utf8_lossy(&x.0).to_string(),
+                        value: name.to_string(),
-                    description: x.1,
+                        description,
-                    span: reedline::Span::new(span.start - offset, span.end - offset),
+                        span: sugg_span,
                         append_whitespace: true,
                         ..Suggestion::default()
                     },
-                kind: Some(SuggestionKind::Command(x.2)),
+                    kind: Some(SuggestionKind::Command(typ)),
-            })
-            .collect::<Vec<_>>();
-
-        let partial = working_set.get_span_contents(span);
-        let partial = String::from_utf8_lossy(partial).to_string();
-
-        if find_externals {
-            let results_external = self
-                .external_command_completion(working_set, &partial, match_algorithm)
-                .into_iter()
-                .map(move |x| SemanticSuggestion {
-                    suggestion: Suggestion {
-                        value: x,
-                        span: reedline::Span::new(span.start - offset, span.end - offset),
-                        append_whitespace: true,
-                        ..Suggestion::default()
                 },
-                    // TODO: is there a way to create a test?
+            );
-                    kind: None,
+        }
-                });
 
-            let results_strings: Vec<String> =
+        let mut external_suggs = if find_externals {
-                results.iter().map(|x| x.suggestion.value.clone()).collect();
+            self.external_command_completion(
-
+                working_set,
-            for external in results_external {
+                sugg_span,
-                if results_strings.contains(&external.suggestion.value) {
+                |name| internal_suggs.contains_key(name),
-                    results.push(SemanticSuggestion {
+                &mut matcher,
-                        suggestion: Suggestion {
+            )
-                            value: format!("^{}", external.suggestion.value),
-                            span: external.suggestion.span,
-                            append_whitespace: true,
-                            ..Suggestion::default()
-                        },
-                        kind: external.kind,
-                    })
         } else {
-                    results.push(external)
+            HashMap::new()
-                }
+        };
-            }
 
-            results
+        let mut res = Vec::new();
-        } else {
+        for cmd_name in matcher.results() {
-            results
+            if let Some(sugg) = internal_suggs
+                .remove(&cmd_name)
+                .or_else(|| external_suggs.remove(&cmd_name))
+            {
+                res.push(sugg);
             }
         }
+        res
+    }
 }
 
 impl Completer for CommandCompletion {
@@ -158,7 +166,7 @@ impl Completer for CommandCompletion {
         &mut self,
         working_set: &StateWorkingSet,
         _stack: &Stack,
-        prefix: &[u8],
+        _prefix: &[u8],
         span: Span,
         offset: usize,
         pos: usize,
@@ -188,18 +196,18 @@ impl Completer for CommandCompletion {
                 Span::new(last.0.start, pos),
                 offset,
                 false,
-                options.match_algorithm,
+                options,
             )
         } else {
             vec![]
         };
 
         if !subcommands.is_empty() {
-            return sort_suggestions(&String::from_utf8_lossy(prefix), subcommands, options);
+            return subcommands;
         }
 
         let config = working_set.get_config();
-        let commands = if matches!(self.flat_shape, nu_parser::FlatShape::External)
+        if matches!(self.flat_shape, nu_parser::FlatShape::External)
             || matches!(self.flat_shape, nu_parser::FlatShape::InternalCall(_))
             || ((span.end - span.start) == 0)
             || is_passthrough_command(working_set.delta.get_file_contents())
@@ -214,13 +222,11 @@ impl Completer for CommandCompletion {
                 span,
                 offset,
                 config.completions.external.enable,
-                options.match_algorithm,
+                options,
             )
         } else {
             vec![]
-        };
+        }
-
-        sort_suggestions(&String::from_utf8_lossy(prefix), commands, options)
     }
 }
 

crates/nu-cli/src/completions/completion_common.rs

@@ -1,22 +1,20 @@
-use super::MatchAlgorithm;
+use super::{completion_options::NuMatcher, MatchAlgorithm};
-use crate::{
+use crate::completions::CompletionOptions;
-    completions::{matches, CompletionOptions},
-    SemanticSuggestion,
-};
-use fuzzy_matcher::{skim::SkimMatcherV2, FuzzyMatcher};
 use nu_ansi_term::Style;
 use nu_engine::env_to_string;
 use nu_path::dots::expand_ndots;
 use nu_path::{expand_to_real_path, home_dir};
 use nu_protocol::{
     engine::{EngineState, Stack, StateWorkingSet},
-    CompletionSort, Span,
+    Span,
 };
 use nu_utils::get_ls_colors;
+use nu_utils::IgnoreCaseExt;
 use std::path::{is_separator, Component, Path, PathBuf, MAIN_SEPARATOR as SEP};
 
 #[derive(Clone, Default)]
 pub struct PathBuiltFromString {
+    cwd: PathBuf,
     parts: Vec<String>,
     isdir: bool,
 }
@@ -30,35 +28,41 @@ pub struct PathBuiltFromString {
 /// want_directory: Whether we want only directories as completion matches.
 /// Some commands like `cd` can only be run on directories whereas others
 /// like `ls` can be run on regular files as well.
-pub fn complete_rec(
+fn complete_rec(
     partial: &[&str],
-    built: &PathBuiltFromString,
+    built_paths: &[PathBuiltFromString],
-    cwd: &Path,
     options: &CompletionOptions,
     want_directory: bool,
     isdir: bool,
 ) -> Vec<PathBuiltFromString> {
-    let mut completions = vec![];
-
     if let Some((&base, rest)) = partial.split_first() {
         if base.chars().all(|c| c == '.') && (isdir || !rest.is_empty()) {
+            let built_paths: Vec<_> = built_paths
+                .iter()
+                .map(|built| {
                     let mut built = built.clone();
                     built.parts.push(base.to_string());
                     built.isdir = true;
-            return complete_rec(rest, &built, cwd, options, want_directory, isdir);
+                    built
+                })
+                .collect();
+            return complete_rec(rest, &built_paths, options, want_directory, isdir);
         }
     }
 
-    let mut built_path = cwd.to_path_buf();
+    let prefix = partial.first().unwrap_or(&"");
+    let mut matcher = NuMatcher::new(prefix, options.clone());
+
+    for built in built_paths {
+        let mut path = built.cwd.clone();
         for part in &built.parts {
-        built_path.push(part);
+            path.push(part);
         }
 
-    let Ok(result) = built_path.read_dir() else {
+        let Ok(result) = path.read_dir() else {
-        return completions;
+            continue;
         };
 
-    let mut entries = Vec::new();
         for entry in result.filter_map(|e| e.ok()) {
             let entry_name = entry.file_name().to_string_lossy().into_owned();
             let entry_isdir = entry.path().is_dir();
@@ -67,17 +71,15 @@ pub fn complete_rec(
             built.isdir = entry_isdir;
 
             if !want_directory || entry_isdir {
-            entries.push((entry_name, built));
+                matcher.add(entry_name.clone(), (entry_name, built));
+            }
         }
     }
 
-    let prefix = partial.first().unwrap_or(&"");
+    let mut completions = vec![];
-    let sorted_entries = sort_completions(prefix, entries, options, |(entry, _)| entry);
+    for (entry_name, built) in matcher.results() {
-
-    for (entry_name, built) in sorted_entries {
         match partial.split_first() {
             Some((base, rest)) => {
-                if matches(base, &entry_name, options) {
                 // We use `isdir` to confirm that the current component has
                 // at least one next component or a slash.
                 // Serves as confirmation to ignore longer completions for
@@ -85,8 +87,7 @@ pub fn complete_rec(
                 if !rest.is_empty() || isdir {
                     completions.extend(complete_rec(
                         rest,
-                            &built,
+                        &[built],
-                            cwd,
                         options,
                         want_directory,
                         isdir,
@@ -94,14 +95,19 @@ pub fn complete_rec(
                 } else {
                     completions.push(built);
                 }
-                }
+
-                if entry_name.eq(base)
+                // For https://github.com/nushell/nushell/issues/13204
-                    && matches!(options.match_algorithm, MatchAlgorithm::Prefix)
+                if isdir && options.match_algorithm == MatchAlgorithm::Prefix {
-                    && isdir
+                    let exact_match = if options.case_sensitive {
-                {
+                        entry_name.eq(base)
+                    } else {
+                        entry_name.to_folded_case().eq(&base.to_folded_case())
+                    };
+                    if exact_match {
                         break;
                     }
                 }
+            }
             None => {
                 completions.push(built);
             }
@@ -147,15 +153,25 @@ fn surround_remove(partial: &str) -> String {
     partial.to_string()
 }
 
+pub struct FileSuggestion {
+    pub span: nu_protocol::Span,
+    pub path: String,
+    pub style: Option<Style>,
+    pub cwd: PathBuf,
+}
+
+/// # Parameters
+/// * `cwds` - A list of directories in which to search. The only reason this isn't a single string
+///   is because dotnu_completions searches in multiple directories at once
 pub fn complete_item(
     want_directory: bool,
     span: nu_protocol::Span,
     partial: &str,
-    cwd: &str,
+    cwds: &[impl AsRef<str>],
     options: &CompletionOptions,
     engine_state: &EngineState,
     stack: &Stack,
-) -> Vec<(nu_protocol::Span, String, Option<Style>)> {
+) -> Vec<FileSuggestion> {
     let cleaned_partial = surround_remove(partial);
     let isdir = cleaned_partial.ends_with(is_separator);
     let expanded_partial = expand_ndots(Path::new(&cleaned_partial));
@@ -175,7 +191,10 @@ pub fn complete_item(
         partial.push_str(&format!("{path_separator}."));
     }
 
-    let cwd_pathbuf = Path::new(cwd).to_path_buf();
+    let cwd_pathbufs: Vec<_> = cwds
+        .iter()
+        .map(|cwd| Path::new(cwd.as_ref()).to_path_buf())
+        .collect();
     let ls_colors = (engine_state.config.completions.use_ls_colors
         && engine_state.config.use_ansi_coloring)
         .then(|| {
@@ -186,7 +205,7 @@ pub fn complete_item(
             get_ls_colors(ls_colors_env_str)
         });
 
-    let mut cwd = cwd_pathbuf.clone();
+    let mut cwds = cwd_pathbufs.clone();
     let mut prefix_len = 0;
     let mut original_cwd = OriginalCwd::None;
 
@@ -194,19 +213,21 @@ pub fn complete_item(
     match components.peek().cloned() {
         Some(c @ Component::Prefix(..)) => {
             // windows only by definition
-            cwd = [c, Component::RootDir].iter().collect();
+            cwds = vec![[c, Component::RootDir].iter().collect()];
             prefix_len = c.as_os_str().len();
             original_cwd = OriginalCwd::Prefix(c.as_os_str().to_string_lossy().into_owned());
         }
         Some(c @ Component::RootDir) => {
             // This is kind of a hack. When joining an empty string with the rest,
             // we add the slash automagically
-            cwd = PathBuf::from(c.as_os_str());
+            cwds = vec![PathBuf::from(c.as_os_str())];
             prefix_len = 1;
             original_cwd = OriginalCwd::Prefix(String::new());
         }
         Some(Component::Normal(home)) if home.to_string_lossy() == "~" => {
-            cwd = home_dir().map(Into::into).unwrap_or(cwd_pathbuf);
+            cwds = home_dir()
+                .map(|dir| vec![dir.into()])
+                .unwrap_or(cwd_pathbufs);
             prefix_len = 1;
             original_cwd = OriginalCwd::Home;
         }
@@ -223,8 +244,14 @@ pub fn complete_item(
 
     complete_rec(
         partial.as_slice(),
-        &PathBuiltFromString::default(),
+        &cwds
-        &cwd,
+            .into_iter()
+            .map(|cwd| PathBuiltFromString {
+                cwd,
+                parts: Vec::new(),
+                isdir: false,
+            })
+            .collect::<Vec<_>>(),
         options,
         want_directory,
         isdir,
@@ -234,6 +261,7 @@ pub fn complete_item(
         if should_collapse_dots {
             p = collapse_ndots(p);
         }
+        let cwd = p.cwd.clone();
         let path = original_cwd.apply(p, path_separator);
         let style = ls_colors.as_ref().map(|lsc| {
             lsc.style_for_path_with_metadata(
@@ -245,7 +273,12 @@ pub fn complete_item(
             .map(lscolors::Style::to_nu_ansi_term_style)
             .unwrap_or_default()
         });
-        (span, escape_path(path, want_directory), style)
+        FileSuggestion {
+            span,
+            path: escape_path(path, want_directory),
+            style,
+            cwd,
+        }
     })
     .collect()
 }
@@ -310,45 +343,6 @@ pub fn adjust_if_intermediate(
     }
 }
 
-/// Convenience function to sort suggestions using [`sort_completions`]
-pub fn sort_suggestions(
-    prefix: &str,
-    items: Vec<SemanticSuggestion>,
-    options: &CompletionOptions,
-) -> Vec<SemanticSuggestion> {
-    sort_completions(prefix, items, options, |it| &it.suggestion.value)
-}
-
-/// # Arguments
-/// * `prefix` - What the user's typed, for sorting by fuzzy matcher score
-pub fn sort_completions<T>(
-    prefix: &str,
-    mut items: Vec<T>,
-    options: &CompletionOptions,
-    get_value: fn(&T) -> &str,
-) -> Vec<T> {
-    // Sort items
-    if options.sort == CompletionSort::Smart && options.match_algorithm == MatchAlgorithm::Fuzzy {
-        let mut matcher = SkimMatcherV2::default();
-        if options.case_sensitive {
-            matcher = matcher.respect_case();
-        } else {
-            matcher = matcher.ignore_case();
-        };
-        items.sort_unstable_by(|a, b| {
-            let a_str = get_value(a);
-            let b_str = get_value(b);
-            let a_score = matcher.fuzzy_match(a_str, prefix).unwrap_or_default();
-            let b_score = matcher.fuzzy_match(b_str, prefix).unwrap_or_default();
-            b_score.cmp(&a_score).then(a_str.cmp(b_str))
-        });
-    } else {
-        items.sort_unstable_by(|a, b| get_value(a).cmp(get_value(b)));
-    }
-
-    items
-}
-
 /// Collapse multiple ".." components into n-dots.
 ///
 /// It performs the reverse operation of `expand_ndots`, collapsing sequences of ".." into n-dots,
@@ -359,6 +353,7 @@ fn collapse_ndots(path: PathBuiltFromString) -> PathBuiltFromString {
     let mut result = PathBuiltFromString {
         parts: Vec::with_capacity(path.parts.len()),
         isdir: path.isdir,
+        cwd: path.cwd,
     };
 
     let mut dot_count = 0;

crates/nu-cli/src/completions/completion_options.rs

@@ -1,7 +1,10 @@
 use fuzzy_matcher::{skim::SkimMatcherV2, FuzzyMatcher};
 use nu_parser::trim_quotes_str;
 use nu_protocol::{CompletionAlgorithm, CompletionSort};
-use std::fmt::Display;
+use nu_utils::IgnoreCaseExt;
+use std::{borrow::Cow, fmt::Display};
+
+use super::SemanticSuggestion;
 
 /// Describes how suggestions should be matched.
 #[derive(Copy, Clone, Debug, PartialEq)]
@@ -19,32 +22,153 @@ pub enum MatchAlgorithm {
     Fuzzy,
 }
 
-impl MatchAlgorithm {
+pub struct NuMatcher<T> {
-    /// Returns whether the `needle` search text matches the given `haystack`.
+    options: CompletionOptions,
-    pub fn matches_str(&self, haystack: &str, needle: &str) -> bool {
+    needle: String,
+    state: State<T>,
+}
+
+enum State<T> {
+    Prefix {
+        /// Holds (haystack, item)
+        items: Vec<(String, T)>,
+    },
+    Fuzzy {
+        matcher: Box<SkimMatcherV2>,
+        /// Holds (haystack, item, score)
+        items: Vec<(String, T, i64)>,
+    },
+}
+
+/// Filters and sorts suggestions
+impl<T> NuMatcher<T> {
+    /// # Arguments
+    ///
+    /// * `needle` - The text to search for
+    pub fn new(needle: impl AsRef<str>, options: CompletionOptions) -> NuMatcher<T> {
+        let orig_needle = trim_quotes_str(needle.as_ref());
+        let lowercase_needle = if options.case_sensitive {
+            orig_needle.to_owned()
+        } else {
+            orig_needle.to_folded_case()
+        };
+        match options.match_algorithm {
+            MatchAlgorithm::Prefix => NuMatcher {
+                options,
+                needle: lowercase_needle,
+                state: State::Prefix { items: Vec::new() },
+            },
+            MatchAlgorithm::Fuzzy => {
+                let mut matcher = SkimMatcherV2::default();
+                if options.case_sensitive {
+                    matcher = matcher.respect_case();
+                } else {
+                    matcher = matcher.ignore_case();
+                };
+                NuMatcher {
+                    options,
+                    needle: orig_needle.to_owned(),
+                    state: State::Fuzzy {
+                        matcher: Box::new(matcher),
+                        items: Vec::new(),
+                    },
+                }
+            }
+        }
+    }
+
+    /// Returns whether or not the haystack matches the needle. If it does, `item` is added
+    /// to the list of matches (if given).
+    ///
+    /// Helper to avoid code duplication between [NuMatcher::add] and [NuMatcher::matches].
+    fn matches_aux(&mut self, haystack: &str, item: Option<T>) -> bool {
         let haystack = trim_quotes_str(haystack);
-        let needle = trim_quotes_str(needle);
+        match &mut self.state {
-        match *self {
+            State::Prefix { items } => {
-            MatchAlgorithm::Prefix => haystack.starts_with(needle),
+                let haystack_folded = if self.options.case_sensitive {
-            MatchAlgorithm::Fuzzy => {
+                    Cow::Borrowed(haystack)
-                let matcher = SkimMatcherV2::default();
+                } else {
-                matcher.fuzzy_match(haystack, needle).is_some()
+                    Cow::Owned(haystack.to_folded_case())
+                };
+                let matches = if self.options.positional {
+                    haystack_folded.starts_with(self.needle.as_str())
+                } else {
+                    haystack_folded.contains(self.needle.as_str())
+                };
+                if matches {
+                    if let Some(item) = item {
+                        items.push((haystack.to_string(), item));
+                    }
+                }
+                matches
+            }
+            State::Fuzzy { items, matcher } => {
+                let Some(score) = matcher.fuzzy_match(haystack, &self.needle) else {
+                    return false;
+                };
+                if let Some(item) = item {
+                    items.push((haystack.to_string(), item, score));
+                }
+                true
             }
         }
     }
 
-    /// Returns whether the `needle` search text matches the given `haystack`.
+    /// Add the given item if the given haystack matches the needle.
-    pub fn matches_u8(&self, haystack: &[u8], needle: &[u8]) -> bool {
+    ///
-        match *self {
+    /// Returns whether the item was added.
-            MatchAlgorithm::Prefix => haystack.starts_with(needle),
+    pub fn add(&mut self, haystack: impl AsRef<str>, item: T) -> bool {
-            MatchAlgorithm::Fuzzy => {
+        self.matches_aux(haystack.as_ref(), Some(item))
-                let haystack_str = String::from_utf8_lossy(haystack);
+    }
-                let needle_str = String::from_utf8_lossy(needle);
 
-                let matcher = SkimMatcherV2::default();
+    /// Returns whether the haystack matches the needle.
-                matcher.fuzzy_match(&haystack_str, &needle_str).is_some()
+    pub fn matches(&mut self, haystack: &str) -> bool {
+        self.matches_aux(haystack, None)
+    }
+
+    /// Get all the items that matched (sorted)
+    pub fn results(self) -> Vec<T> {
+        match self.state {
+            State::Prefix { mut items, .. } => {
+                items.sort_by(|(haystack1, _), (haystack2, _)| {
+                    let cmp_sensitive = haystack1.cmp(haystack2);
+                    if self.options.case_sensitive {
+                        cmp_sensitive
+                    } else {
+                        haystack1
+                            .to_folded_case()
+                            .cmp(&haystack2.to_folded_case())
+                            .then(cmp_sensitive)
+                    }
+                });
+                items.into_iter().map(|(_, item)| item).collect::<Vec<_>>()
+            }
+            State::Fuzzy { mut items, .. } => {
+                match self.options.sort {
+                    CompletionSort::Alphabetical => {
+                        items.sort_by(|(haystack1, _, _), (haystack2, _, _)| {
+                            haystack1.cmp(haystack2)
+                        });
+                    }
+                    CompletionSort::Smart => {
+                        items.sort_by(|(haystack1, _, score1), (haystack2, _, score2)| {
+                            score2.cmp(score1).then(haystack1.cmp(haystack2))
+                        });
                     }
                 }
+                items
+                    .into_iter()
+                    .map(|(_, item, _)| item)
+                    .collect::<Vec<_>>()
+            }
+        }
+    }
+}
+
+impl NuMatcher<SemanticSuggestion> {
+    pub fn add_semantic_suggestion(&mut self, sugg: SemanticSuggestion) -> bool {
+        let value = sugg.suggestion.value.to_string();
+        self.add(value, sugg)
     }
 }
 
@@ -105,35 +229,49 @@ impl Default for CompletionOptions {
 
 #[cfg(test)]
 mod test {
-    use super::MatchAlgorithm;
+    use rstest::rstest;
 
-    #[test]
+    use super::{CompletionOptions, MatchAlgorithm, NuMatcher};
-    fn match_algorithm_prefix() {
-        let algorithm = MatchAlgorithm::Prefix;
 
-        assert!(algorithm.matches_str("example text", ""));
+    #[rstest]
-        assert!(algorithm.matches_str("example text", "examp"));
+    #[case(MatchAlgorithm::Prefix, "example text", "", true)]
-        assert!(!algorithm.matches_str("example text", "text"));
+    #[case(MatchAlgorithm::Prefix, "example text", "examp", true)]
-
+    #[case(MatchAlgorithm::Prefix, "example text", "text", false)]
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[]));
+    #[case(MatchAlgorithm::Fuzzy, "example text", "", true)]
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[1, 2]));
+    #[case(MatchAlgorithm::Fuzzy, "example text", "examp", true)]
-        assert!(!algorithm.matches_u8(&[1, 2, 3], &[2, 3]));
+    #[case(MatchAlgorithm::Fuzzy, "example text", "ext", true)]
+    #[case(MatchAlgorithm::Fuzzy, "example text", "mplxt", true)]
+    #[case(MatchAlgorithm::Fuzzy, "example text", "mpp", false)]
+    fn match_algorithm_simple(
+        #[case] match_algorithm: MatchAlgorithm,
+        #[case] haystack: &str,
+        #[case] needle: &str,
+        #[case] should_match: bool,
+    ) {
+        let options = CompletionOptions {
+            match_algorithm,
+            ..Default::default()
+        };
+        let mut matcher = NuMatcher::new(needle, options);
+        matcher.add(haystack, haystack);
+        if should_match {
+            assert_eq!(vec![haystack], matcher.results());
+        } else {
+            assert_ne!(vec![haystack], matcher.results());
+        }
     }
 
     #[test]
-    fn match_algorithm_fuzzy() {
+    fn match_algorithm_fuzzy_sort_score() {
-        let algorithm = MatchAlgorithm::Fuzzy;
+        let options = CompletionOptions {
-
+            match_algorithm: MatchAlgorithm::Fuzzy,
-        assert!(algorithm.matches_str("example text", ""));
+            ..Default::default()
-        assert!(algorithm.matches_str("example text", "examp"));
+        };
-        assert!(algorithm.matches_str("example text", "ext"));
+        let mut matcher = NuMatcher::new("fob", options);
-        assert!(algorithm.matches_str("example text", "mplxt"));
+        for item in ["foo/bar", "fob", "foo bar"] {
-        assert!(!algorithm.matches_str("example text", "mpp"));
+            matcher.add(item, item);
-
+        }
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[]));
+        // Sort by score, then in alphabetical order
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[1, 2]));
+        assert_eq!(vec!["fob", "foo bar", "foo/bar"], matcher.results());
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[2, 3]));
-        assert!(algorithm.matches_u8(&[1, 2, 3], &[1, 3]));
-        assert!(!algorithm.matches_u8(&[1, 2, 3], &[2, 2]));
     }
 }

crates/nu-cli/src/completions/custom_completions.rs

@@ -9,10 +9,9 @@ use nu_protocol::{
     engine::{Stack, StateWorkingSet},
     CompletionSort, DeclId, PipelineData, Span, Type, Value,
 };
-use nu_utils::IgnoreCaseExt;
 use std::collections::HashMap;
 
-use super::completion_common::sort_suggestions;
+use super::completion_options::NuMatcher;
 
 pub struct CustomCompletion {
     stack: Stack,
@@ -123,41 +122,11 @@ impl Completer for CustomCompletion {
             })
             .unwrap_or_default();
 
-        let options = custom_completion_options
+        let options = custom_completion_options.unwrap_or(completion_options.clone());
-            .as_ref()
+        let mut matcher = NuMatcher::new(String::from_utf8_lossy(prefix), options);
-            .unwrap_or(completion_options);
+        for sugg in suggestions {
-        let suggestions = filter(prefix, suggestions, options);
+            matcher.add_semantic_suggestion(sugg);
-        sort_suggestions(&String::from_utf8_lossy(prefix), suggestions, options)
+        }
+        matcher.results()
     }
 }
-
-fn filter(
-    prefix: &[u8],
-    items: Vec<SemanticSuggestion>,
-    options: &CompletionOptions,
-) -> Vec<SemanticSuggestion> {
-    items
-        .into_iter()
-        .filter(|it| match options.match_algorithm {
-            MatchAlgorithm::Prefix => match (options.case_sensitive, options.positional) {
-                (true, true) => it.suggestion.value.as_bytes().starts_with(prefix),
-                (true, false) => it
-                    .suggestion
-                    .value
-                    .contains(std::str::from_utf8(prefix).unwrap_or("")),
-                (false, positional) => {
-                    let value = it.suggestion.value.to_folded_case();
-                    let prefix = std::str::from_utf8(prefix).unwrap_or("").to_folded_case();
-                    if positional {
-                        value.starts_with(&prefix)
-                    } else {
-                        value.contains(&prefix)
-                    }
-                }
-            },
-            MatchAlgorithm::Fuzzy => options
-                .match_algorithm
-                .matches_u8(it.suggestion.value.as_bytes(), prefix),
-        })
-        .collect()
-}

crates/nu-cli/src/completions/directory_completions.rs

@@ -2,7 +2,6 @@ use crate::completions::{
     completion_common::{adjust_if_intermediate, complete_item, AdjustView},
     Completer, CompletionOptions,
 };
-use nu_ansi_term::Style;
 use nu_protocol::{
     engine::{EngineState, Stack, StateWorkingSet},
     Span,
@@ -10,7 +9,7 @@ use nu_protocol::{
 use reedline::Suggestion;
 use std::path::Path;
 
-use super::SemanticSuggestion;
+use super::{completion_common::FileSuggestion, SemanticSuggestion};
 
 #[derive(Clone, Default)]
 pub struct DirectoryCompletion {}
@@ -47,11 +46,11 @@ impl Completer for DirectoryCompletion {
         .into_iter()
         .map(move |x| SemanticSuggestion {
             suggestion: Suggestion {
-                value: x.1,
+                value: x.path,
-                style: x.2,
+                style: x.style,
                 span: reedline::Span {
-                    start: x.0.start - offset,
+                    start: x.span.start - offset,
-                    end: x.0.end - offset,
+                    end: x.span.end - offset,
                 },
                 ..Suggestion::default()
             },
@@ -92,6 +91,6 @@ pub fn directory_completion(
     options: &CompletionOptions,
     engine_state: &EngineState,
     stack: &Stack,
-) -> Vec<(nu_protocol::Span, String, Option<Style>)> {
+) -> Vec<FileSuggestion> {
-    complete_item(true, span, partial, cwd, options, engine_state, stack)
+    complete_item(true, span, partial, &[cwd], options, engine_state, stack)
 }

crates/nu-cli/src/completions/dotnu_completions.rs

@@ -6,7 +6,7 @@ use nu_protocol::{
 use reedline::Suggestion;
 use std::path::{is_separator, Path, MAIN_SEPARATOR as SEP, MAIN_SEPARATOR_STR};
 
-use super::{completion_common::sort_suggestions, SemanticSuggestion};
+use super::SemanticSuggestion;
 
 #[derive(Clone, Default)]
 pub struct DotNuCompletion {}
@@ -87,13 +87,11 @@ impl Completer for DotNuCompletion {
 
         // Fetch the files filtering the ones that ends with .nu
         // and transform them into suggestions
-        let output: Vec<SemanticSuggestion> = search_dirs
+
-            .into_iter()
-            .flat_map(|search_dir| {
         let completions = file_path_completion(
             span,
             &partial,
-                    &search_dir,
+            &search_dirs.iter().map(|d| d.as_str()).collect::<Vec<_>>(),
             options,
             working_set.permanent_state,
             stack,
@@ -103,23 +101,23 @@ impl Completer for DotNuCompletion {
             .filter(move |it| {
                 // Different base dir, so we list the .nu files or folders
                 if !is_current_folder {
-                            it.1.ends_with(".nu") || it.1.ends_with(SEP)
+                    it.path.ends_with(".nu") || it.path.ends_with(SEP)
                 } else {
                     // Lib dirs, so we filter only the .nu files or directory modules
-                            if it.1.ends_with(SEP) {
+                    if it.path.ends_with(SEP) {
-                                Path::new(&search_dir).join(&it.1).join("mod.nu").exists()
+                        Path::new(&it.cwd).join(&it.path).join("mod.nu").exists()
                     } else {
-                                it.1.ends_with(".nu")
+                        it.path.ends_with(".nu")
                     }
                 }
             })
             .map(move |x| SemanticSuggestion {
                 suggestion: Suggestion {
-                            value: x.1,
+                    value: x.path,
-                            style: x.2,
+                    style: x.style,
                     span: reedline::Span {
-                                start: x.0.start - offset,
+                        start: x.span.start - offset,
-                                end: x.0.end - offset,
+                        end: x.span.end - offset,
                     },
                     append_whitespace: true,
                     ..Suggestion::default()
@@ -127,9 +125,6 @@ impl Completer for DotNuCompletion {
                 // TODO????
                 kind: None,
             })
-            })
+            .collect::<Vec<_>>()
-            .collect();
-
-        sort_suggestions(&prefix_str, output, options)
     }
 }

crates/nu-cli/src/completions/file_completions.rs

@@ -2,16 +2,14 @@ use crate::completions::{
     completion_common::{adjust_if_intermediate, complete_item, AdjustView},
     Completer, CompletionOptions,
 };
-use nu_ansi_term::Style;
 use nu_protocol::{
     engine::{EngineState, Stack, StateWorkingSet},
     Span,
 };
-use nu_utils::IgnoreCaseExt;
 use reedline::Suggestion;
 use std::path::Path;
 
-use super::SemanticSuggestion;
+use super::{completion_common::FileSuggestion, SemanticSuggestion};
 
 #[derive(Clone, Default)]
 pub struct FileCompletion {}
@@ -44,7 +42,7 @@ impl Completer for FileCompletion {
             readjusted,
             span,
             &prefix,
-            &working_set.permanent_state.current_work_dir(),
+            &[&working_set.permanent_state.current_work_dir()],
             options,
             working_set.permanent_state,
             stack,
@@ -52,11 +50,11 @@ impl Completer for FileCompletion {
         .into_iter()
         .map(move |x| SemanticSuggestion {
             suggestion: Suggestion {
-                value: x.1,
+                value: x.path,
-                style: x.2,
+                style: x.style,
                 span: reedline::Span {
-                    start: x.0.start - offset,
+                    start: x.span.start - offset,
-                    end: x.0.end - offset,
+                    end: x.span.end - offset,
                 },
                 ..Suggestion::default()
             },
@@ -95,21 +93,10 @@ impl Completer for FileCompletion {
 pub fn file_path_completion(
     span: nu_protocol::Span,
     partial: &str,
-    cwd: &str,
+    cwds: &[impl AsRef<str>],
     options: &CompletionOptions,
     engine_state: &EngineState,
     stack: &Stack,
-) -> Vec<(nu_protocol::Span, String, Option<Style>)> {
+) -> Vec<FileSuggestion> {
-    complete_item(false, span, partial, cwd, options, engine_state, stack)
+    complete_item(false, span, partial, cwds, options, engine_state, stack)
-}
-
-pub fn matches(partial: &str, from: &str, options: &CompletionOptions) -> bool {
-    // Check for case sensitive
-    if !options.case_sensitive {
-        return options
-            .match_algorithm
-            .matches_str(&from.to_folded_case(), &partial.to_folded_case());
-    }
-
-    options.match_algorithm.matches_str(from, partial)
 }

crates/nu-cli/src/completions/flag_completions.rs

@@ -1,4 +1,4 @@
-use crate::completions::{completion_common::sort_suggestions, Completer, CompletionOptions};
+use crate::completions::{completion_options::NuMatcher, Completer, CompletionOptions};
 use nu_protocol::{
     ast::{Expr, Expression},
     engine::{Stack, StateWorkingSet},
@@ -35,7 +35,7 @@ impl Completer for FlagCompletion {
             let decl = working_set.get_decl(call.decl_id);
             let sig = decl.signature();
 
-            let mut output = vec![];
+            let mut matcher = NuMatcher::new(String::from_utf8_lossy(prefix), options.clone());
 
             for named in &sig.named {
                 let flag_desc = &named.desc;
@@ -44,8 +44,7 @@ impl Completer for FlagCompletion {
                     short.encode_utf8(&mut named);
                     named.insert(0, b'-');
 
-                    if options.match_algorithm.matches_u8(&named, prefix) {
+                    matcher.add_semantic_suggestion(SemanticSuggestion {
-                        output.push(SemanticSuggestion {
                         suggestion: Suggestion {
                             value: String::from_utf8_lossy(&named).to_string(),
                             description: Some(flag_desc.to_string()),
@@ -60,7 +59,6 @@ impl Completer for FlagCompletion {
                         kind: None,
                     });
                 }
-                }
 
                 if named.long.is_empty() {
                     continue;
@@ -70,8 +68,7 @@ impl Completer for FlagCompletion {
                 named.insert(0, b'-');
                 named.insert(0, b'-');
 
-                if options.match_algorithm.matches_u8(&named, prefix) {
+                matcher.add_semantic_suggestion(SemanticSuggestion {
-                    output.push(SemanticSuggestion {
                     suggestion: Suggestion {
                         value: String::from_utf8_lossy(&named).to_string(),
                         description: Some(flag_desc.to_string()),
@@ -86,9 +83,8 @@ impl Completer for FlagCompletion {
                     kind: None,
                 });
             }
-            }
 
-            return sort_suggestions(&String::from_utf8_lossy(prefix), output, options);
+            return matcher.results();
         }
 
         vec![]

crates/nu-cli/src/completions/mod.rs

@@ -18,7 +18,7 @@ pub use completion_options::{CompletionOptions, MatchAlgorithm};
 pub use custom_completions::CustomCompletion;
 pub use directory_completions::DirectoryCompletion;
 pub use dotnu_completions::DotNuCompletion;
-pub use file_completions::{file_path_completion, matches, FileCompletion};
+pub use file_completions::{file_path_completion, FileCompletion};
 pub use flag_completions::FlagCompletion;
 pub use operator_completions::OperatorCompletion;
 pub use variable_completions::VariableCompletion;

crates/nu-cli/src/completions/operator_completions.rs

@@ -1,5 +1,5 @@
 use crate::completions::{
-    Completer, CompletionOptions, MatchAlgorithm, SemanticSuggestion, SuggestionKind,
+    completion_options::NuMatcher, Completer, CompletionOptions, SemanticSuggestion, SuggestionKind,
 };
 use nu_protocol::{
     ast::{Expr, Expression},
@@ -28,7 +28,7 @@ impl Completer for OperatorCompletion {
         span: Span,
         offset: usize,
         _pos: usize,
-        _options: &CompletionOptions,
+        options: &CompletionOptions,
     ) -> Vec<SemanticSuggestion> {
         //Check if int, float, or string
         let partial = std::str::from_utf8(working_set.get_span_contents(span)).unwrap_or("");
@@ -129,17 +129,12 @@ impl Completer for OperatorCompletion {
             _ => vec![],
         };
 
-        let match_algorithm = MatchAlgorithm::Prefix;
+        let mut matcher = NuMatcher::new(partial, options.clone());
-        let input_fuzzy_search =
+        for (symbol, desc) in possible_operations.into_iter() {
-            |(operator, _): &(&str, &str)| match_algorithm.matches_str(operator, partial);
+            matcher.add_semantic_suggestion(SemanticSuggestion {
-
-        possible_operations
-            .into_iter()
-            .filter(input_fuzzy_search)
-            .map(move |x| SemanticSuggestion {
                 suggestion: Suggestion {
-                    value: x.0.to_string(),
+                    value: symbol.to_string(),
-                    description: Some(x.1.to_string()),
+                    description: Some(desc.to_string()),
                     span: reedline::Span::new(span.start - offset, span.end - offset),
                     append_whitespace: true,
                     ..Suggestion::default()
@@ -147,8 +142,9 @@ impl Completer for OperatorCompletion {
                 kind: Some(SuggestionKind::Command(
                     nu_protocol::engine::CommandType::Builtin,
                 )),
-            })
+            });
-            .collect()
+        }
+        matcher.results()
     }
 }
 

crates/nu-cli/src/completions/variable_completions.rs

@@ -1,6 +1,4 @@
-use crate::completions::{
+use crate::completions::{Completer, CompletionOptions, SemanticSuggestion, SuggestionKind};
-    Completer, CompletionOptions, MatchAlgorithm, SemanticSuggestion, SuggestionKind,
-};
 use nu_engine::{column::get_columns, eval_variable};
 use nu_protocol::{
     engine::{Stack, StateWorkingSet},
@@ -9,7 +7,7 @@ use nu_protocol::{
 use reedline::Suggestion;
 use std::str;
 
-use super::completion_common::sort_suggestions;
+use super::completion_options::NuMatcher;
 
 #[derive(Clone)]
 pub struct VariableCompletion {
@@ -33,7 +31,6 @@ impl Completer for VariableCompletion {
         _pos: usize,
         options: &CompletionOptions,
     ) -> Vec<SemanticSuggestion> {
-        let mut output = vec![];
         let builtins = ["$nu", "$in", "$env"];
         let var_str = std::str::from_utf8(&self.var_context.0).unwrap_or("");
         let var_id = working_set.find_variable(&self.var_context.0);
@@ -43,6 +40,7 @@ impl Completer for VariableCompletion {
         };
         let sublevels_count = self.var_context.1.len();
         let prefix_str = String::from_utf8_lossy(prefix);
+        let mut matcher = NuMatcher::new(prefix_str, options.clone());
 
         // Completions for the given variable
         if !var_str.is_empty() {
@@ -63,26 +61,15 @@ impl Completer for VariableCompletion {
 
                     if let Some(val) = env_vars.get(&target_var_str) {
                         for suggestion in nested_suggestions(val, &nested_levels, current_span) {
-                            if options.match_algorithm.matches_u8_insensitive(
+                            matcher.add_semantic_suggestion(suggestion);
-                                options.case_sensitive,
-                                suggestion.suggestion.value.as_bytes(),
-                                prefix,
-                            ) {
-                                output.push(suggestion);
-                            }
                         }
 
-                        return sort_suggestions(&prefix_str, output, options);
+                        return matcher.results();
                     }
                 } else {
                     // No nesting provided, return all env vars
                     for env_var in env_vars {
-                        if options.match_algorithm.matches_u8_insensitive(
+                        matcher.add_semantic_suggestion(SemanticSuggestion {
-                            options.case_sensitive,
-                            env_var.0.as_bytes(),
-                            prefix,
-                        ) {
-                            output.push(SemanticSuggestion {
                             suggestion: Suggestion {
                                 value: env_var.0,
                                 span: current_span,
@@ -91,9 +78,8 @@ impl Completer for VariableCompletion {
                             kind: Some(SuggestionKind::Type(env_var.1.get_type())),
                         });
                     }
-                    }
 
-                    return sort_suggestions(&prefix_str, output, options);
+                    return matcher.results();
                 }
             }
 
@@ -108,16 +94,10 @@ impl Completer for VariableCompletion {
                 ) {
                     for suggestion in nested_suggestions(&nuval, &self.var_context.1, current_span)
                     {
-                        if options.match_algorithm.matches_u8_insensitive(
+                        matcher.add_semantic_suggestion(suggestion);
-                            options.case_sensitive,
-                            suggestion.suggestion.value.as_bytes(),
-                            prefix,
-                        ) {
-                            output.push(suggestion);
-                        }
                     }
 
-                    return sort_suggestions(&prefix_str, output, options);
+                    return matcher.results();
                 }
             }
 
@@ -130,28 +110,17 @@ impl Completer for VariableCompletion {
                 if let Ok(value) = var {
                     for suggestion in nested_suggestions(&value, &self.var_context.1, current_span)
                     {
-                        if options.match_algorithm.matches_u8_insensitive(
+                        matcher.add_semantic_suggestion(suggestion);
-                            options.case_sensitive,
-                            suggestion.suggestion.value.as_bytes(),
-                            prefix,
-                        ) {
-                            output.push(suggestion);
-                        }
                     }
 
-                    return sort_suggestions(&prefix_str, output, options);
+                    return matcher.results();
                 }
             }
         }
 
         // Variable completion (e.g: $en<tab> to complete $env)
         for builtin in builtins {
-            if options.match_algorithm.matches_u8_insensitive(
+            matcher.add_semantic_suggestion(SemanticSuggestion {
-                options.case_sensitive,
-                builtin.as_bytes(),
-                prefix,
-            ) {
-                output.push(SemanticSuggestion {
                 suggestion: Suggestion {
                     value: builtin.to_string(),
                     span: current_span,
@@ -161,7 +130,6 @@ impl Completer for VariableCompletion {
                 kind: None,
             });
         }
-        }
 
         // TODO: The following can be refactored (see find_commands_by_predicate() used in
         // command_completions).
@@ -170,12 +138,7 @@ impl Completer for VariableCompletion {
         for scope_frame in working_set.delta.scope.iter().rev() {
             for overlay_frame in scope_frame.active_overlays(&mut removed_overlays).rev() {
                 for v in &overlay_frame.vars {
-                    if options.match_algorithm.matches_u8_insensitive(
+                    matcher.add_semantic_suggestion(SemanticSuggestion {
-                        options.case_sensitive,
-                        v.0,
-                        prefix,
-                    ) {
-                        output.push(SemanticSuggestion {
                         suggestion: Suggestion {
                             value: String::from_utf8_lossy(v.0).to_string(),
                             span: current_span,
@@ -188,7 +151,6 @@ impl Completer for VariableCompletion {
                 }
             }
         }
-        }
 
         // Permanent state vars
         // for scope in &self.engine_state.scope {
@@ -198,12 +160,7 @@ impl Completer for VariableCompletion {
             .rev()
         {
             for v in &overlay_frame.vars {
-                if options.match_algorithm.matches_u8_insensitive(
+                matcher.add_semantic_suggestion(SemanticSuggestion {
-                    options.case_sensitive,
-                    v.0,
-                    prefix,
-                ) {
-                    output.push(SemanticSuggestion {
                     suggestion: Suggestion {
                         value: String::from_utf8_lossy(v.0).to_string(),
                         span: current_span,
@@ -215,13 +172,8 @@ impl Completer for VariableCompletion {
                 });
             }
         }
-        }
 
-        output = sort_suggestions(&prefix_str, output, options);
+        matcher.results()
-
-        output.dedup(); // TODO: Removes only consecutive duplicates, is it intended?
-
-        output
     }
 }
 
@@ -302,13 +254,3 @@ fn recursive_value(val: &Value, sublevels: &[Vec<u8>]) -> Result<Value, Span> {
         Ok(val.clone())
     }
 }
-
-impl MatchAlgorithm {
-    pub fn matches_u8_insensitive(&self, sensitive: bool, haystack: &[u8], needle: &[u8]) -> bool {
-        if sensitive {
-            self.matches_u8(haystack, needle)
-        } else {
-            self.matches_u8(&haystack.to_ascii_lowercase(), &needle.to_ascii_lowercase())
-        }
-    }
-}

crates/nu-cli/tests/completions/mod.rs

@@ -890,8 +890,8 @@ fn subcommand_completions(mut subcommand_completer: NuCompleter) {
     match_suggestions(
         &vec![
             "foo bar".to_string(),
-            "foo aabcrr".to_string(),
             "foo abaz".to_string(),
+            "foo aabcrr".to_string(),
         ],
         &suggestions,
     );
@@ -955,8 +955,8 @@ fn flag_completions() {
         "--mime-type".into(),
         "--short-names".into(),
         "--threads".into(),
-        "-D".into(),
         "-a".into(),
+        "-D".into(),
         "-d".into(),
         "-f".into(),
         "-h".into(),
@@ -1287,7 +1287,7 @@ fn variables_completions() {
     assert_eq!(3, suggestions.len());
 
     #[cfg(windows)]
-    let expected: Vec<String> = vec!["PWD".into(), "Path".into(), "TEST".into()];
+    let expected: Vec<String> = vec!["Path".into(), "PWD".into(), "TEST".into()];
     #[cfg(not(windows))]
     let expected: Vec<String> = vec!["PATH".into(), "PWD".into(), "TEST".into()];
 
@@ -1576,6 +1576,23 @@ fn sort_fuzzy_completions_in_alphabetical_order(mut fuzzy_alpha_sort_completer:
     );
 }
 
+#[test]
+fn exact_match() {
+    let (dir, _, engine, stack) = new_partial_engine();
+
+    let mut completer = NuCompleter::new(Arc::new(engine), Arc::new(stack));
+
+    let target_dir = format!("open {}", folder(dir.join("pArTiAL")));
+    let suggestions = completer.complete(&target_dir, target_dir.len());
+
+    // Since it's an exact match, only 'partial' should be suggested, not
+    // 'partial-a' and stuff. Implemented in #13302
+    match_suggestions(
+        &vec![file(dir.join("partial").join("hello.txt"))],
+        &suggestions,
+    );
+}
+
 #[ignore = "was reverted, still needs fixing"]
 #[rstest]
 fn alias_offset_bug_7648() {

crates/nu-protocol/src/engine/engine_state.rs

@@ -698,7 +698,7 @@ impl EngineState {
 
     pub fn find_commands_by_predicate(
         &self,
-        predicate: impl Fn(&[u8]) -> bool,
+        mut predicate: impl FnMut(&[u8]) -> bool,
         ignore_deprecated: bool,
     ) -> Vec<(Vec<u8>, Option<String>, CommandType)> {
         let mut output = vec![];

crates/nu-protocol/src/engine/state_working_set.rs

@@ -724,7 +724,7 @@ impl<'a> StateWorkingSet<'a> {
 
     pub fn find_commands_by_predicate(
         &self,
-        predicate: impl Fn(&[u8]) -> bool,
+        mut predicate: impl FnMut(&[u8]) -> bool,
         ignore_deprecated: bool,
     ) -> Vec<(Vec<u8>, Option<String>, CommandType)> {
         let mut output = vec![];