Fix quoting in to nuon and refactor quoting functions (#14180)

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# Description
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This PR fixes the quoting and escaping of column names in `to nuon`.
Before the PR, column names with quotes inside them would get quoted,
but not escaped:

```nushell
> { 'a"b': 2 } | to nuon
{ "a"b": 2 }

> { 'a"b': 2 } | to nuon | from nuon
Error:   × error when loading nuon text
   ╭─[entry #1:1:27]
 1 │ { "a\"b": 2 } | to nuon | from nuon
   ·                           ────┬────
   ·                               ╰── could not load nuon text
   ╰────

Error:   × error when parsing nuon text
   ╭─[entry #1:1:27]
 1 │ { "a\"b": 2 } | to nuon | from nuon
   ·                           ────┬────
   ·                               ╰── could not parse nuon text
   ╰────

Error:   × error when parsing
   ╭────
 1 │ {"a"b": 2}
   ·          ┬
   ·          ╰── Unexpected end of code.
   ╰────

> [['a"b']; [2] [3]] | to nuon
[["a"b"]; [2], [3]]

> [['a"b']; [2] [3]] | to nuon | from nuon
Error:   × error when loading nuon text
   ╭─[entry #1:1:32]
 1 │ [['a"b']; [2] [3]] | to nuon | from nuon
   ·                                ────┬────
   ·                                    ╰── could not load nuon text
   ╰────

Error:   × error when parsing nuon text
   ╭─[entry #1:1:32]
 1 │ [['a"b']; [2] [3]] | to nuon | from nuon
   ·                                ────┬────
   ·                                    ╰── could not parse nuon text
   ╰────

Error:   × error when parsing
   ╭────
 1 │ [["a"b"]; [2], [3]]
   ·                   ┬
   ·                   ╰── Unexpected end of code.
   ╰────
```

After this PR, the quote is escaped properly:

```nushell
> { 'a"b': 2 } | to nuon
{ "a\"b": 2 }

> { 'a"b': 2 } | to nuon | from nuon
╭─────┬───╮
│ a"b │ 2 │
╰─────┴───╯

> [['a"b']; [2] [3]] | to nuon
[["a\"b"]; [2], [3]]

> [['a"b']; [2] [3]] | to nuon | from nuon
╭─────╮
│ a"b │
├─────┤
│   2 │
│   3 │
╰─────╯
```

The cause of the issue was that `to nuon` simply wrapped column names in
`'"'` instead of calling `escape_quote_string`.

As part of this change, I also moved the functions related to quoting
(`needs_quoting` and `escape_quote_string`) into `nu-utils`, since
previously they were defined in very ad-hoc places (and, in the case of
`escape_quote_string`, it was defined multiple times with the same
body!).

# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->

`to nuon` now properly escapes quotes in column names.

# Tests + Formatting
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All tests pass, including workspace and stdlib tests.

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Cargo.lock

@@ -3317,6 +3317,7 @@ dependencies = [
  "nu-path",
  "nu-plugin-engine",
  "nu-protocol",
+ "nu-utils",
  "rstest",
  "serde_json",
 ]
@@ -3522,10 +3523,12 @@ name = "nu-utils"
 version = "0.99.2"
 dependencies = [
  "crossterm_winapi",
+ "fancy-regex",
  "log",
  "lscolors",
  "nix 0.29.0",
  "num-format",
+ "once_cell",
  "serde",
  "strip-ansi-escapes",
  "sys-locale",
@@ -3755,11 +3758,10 @@ name = "nuon"
 version = "0.99.2"
 dependencies = [
  "chrono",
- "fancy-regex",
  "nu-engine",
  "nu-parser",
  "nu-protocol",
- "once_cell",
+ "nu-utils",
 ]
 
 [[package]]

crates/nu-cli/src/util.rs

@@ -1,6 +1,6 @@
 use nu_cmd_base::hook::eval_hook;
 use nu_engine::{eval_block, eval_block_with_early_return};
-use nu_parser::{escape_quote_string, lex, parse, unescape_unquote_string, Token, TokenContents};
+use nu_parser::{lex, parse, unescape_unquote_string, Token, TokenContents};
 use nu_protocol::{
     cli_error::report_compile_error,
     debugger::WithoutDebug,
@@ -10,7 +10,7 @@ use nu_protocol::{
 };
 #[cfg(windows)]
 use nu_utils::enable_vt_processing;
-use nu_utils::perf;
+use nu_utils::{escape_quote_string, perf};
 use std::path::Path;
 
 // This will collect environment variables from std::env and adds them to a stack.

crates/nu-parser/Cargo.toml

@@ -19,6 +19,7 @@ nu-engine = { path = "../nu-engine", version = "0.99.2" }
 nu-path = { path = "../nu-path", version = "0.99.2" }
 nu-plugin-engine = { path = "../nu-plugin-engine", optional = true, version = "0.99.2" }
 nu-protocol = { path = "../nu-protocol", version = "0.99.2" }
+nu-utils = { path = "../nu-utils", version = "0.99.2" }
 
 bytesize = { workspace = true }
 chrono = { default-features = false, features = ['std'], workspace = true }

crates/nu-parser/src/deparse.rs

@@ -1,3 +1,5 @@
+use nu_utils::escape_quote_string;
+
 fn string_should_be_quoted(input: &str) -> bool {
     input.starts_with('$')
         || input
@@ -5,21 +7,6 @@ fn string_should_be_quoted(input: &str) -> bool {
             .any(|c| c == ' ' || c == '(' || c == '\'' || c == '`' || c == '"' || c == '\\')
 }
 
-pub fn escape_quote_string(input: &str) -> String {
-    let mut output = String::with_capacity(input.len() + 2);
-    output.push('"');
-
-    for c in input.chars() {
-        if c == '"' || c == '\\' {
-            output.push('\\');
-        }
-        output.push(c);
-    }
-
-    output.push('"');
-    output
-}
-
 // Escape rules:
 // input argument is not a flag, does not start with $ and doesn't contain special characters, it is passed as it is (foo -> foo)
 // input argument is not a flag and either starts with $ or contains special characters, quotes are added, " and \ are escaped (two \words -> "two \\words")

crates/nu-parser/src/lib.rs

@@ -11,7 +11,7 @@ mod parse_shape_specs;
 mod parser;
 mod type_check;
 
-pub use deparse::{escape_for_script_arg, escape_quote_string};
+pub use deparse::escape_for_script_arg;
 pub use flatten::{
     flatten_block, flatten_expression, flatten_pipeline, flatten_pipeline_element, FlatShape,
 };

crates/nu-test-support/src/macros.rs

@@ -235,6 +235,7 @@ macro_rules! nu_with_plugins {
 
 use crate::{Outcome, NATIVE_PATH_ENV_VAR};
 use nu_path::{AbsolutePath, AbsolutePathBuf, Path, PathBuf};
+use nu_utils::escape_quote_string;
 use std::{
     ffi::OsStr,
     process::{Command, Stdio},
@@ -421,21 +422,6 @@ where
     Outcome::new(out, err.into_owned(), output.status)
 }
 
-fn escape_quote_string(input: &str) -> String {
-    let mut output = String::with_capacity(input.len() + 2);
-    output.push('"');
-
-    for c in input.chars() {
-        if c == '"' || c == '\\' {
-            output.push('\\');
-        }
-        output.push(c);
-    }
-
-    output.push('"');
-    output
-}
-
 fn with_exe(name: &str) -> String {
     #[cfg(windows)]
     {

crates/nu-utils/Cargo.toml

@@ -17,9 +17,11 @@ bench = false
 bench = false
 
 [dependencies]
+fancy-regex = { workspace = true }
 lscolors = { workspace = true, default-features = false, features = ["nu-ansi-term"] }
 log = { workspace = true }
 num-format = { workspace = true }
+once_cell = { workspace = true }
 strip-ansi-escapes = { workspace = true }
 serde = { workspace = true }
 sys-locale = "0.3"

crates/nu-utils/src/lib.rs

@@ -4,6 +4,7 @@ mod deansi;
 pub mod emoji;
 pub mod filesystem;
 pub mod locale;
+mod quoting;
 mod shared_cow;
 pub mod utils;
 
@@ -18,6 +19,7 @@ pub use deansi::{
     strip_ansi_likely, strip_ansi_string_likely, strip_ansi_string_unlikely, strip_ansi_unlikely,
 };
 pub use emoji::contains_emoji;
+pub use quoting::{escape_quote_string, needs_quoting};
 pub use shared_cow::SharedCow;
 
 #[cfg(unix)]

crates/nu-utils/src/quoting.rs

@@ -0,0 +1,43 @@
+use fancy_regex::Regex;
+use once_cell::sync::Lazy;
+
+// This hits, in order:
+// • Any character of []:`{}#'";()|$,
+// • Any digit (\d)
+// • Any whitespace (\s)
+// • Case-insensitive sign-insensitive float "keywords" inf, infinity and nan.
+static NEEDS_QUOTING_REGEX: Lazy<Regex> = Lazy::new(|| {
+    Regex::new(r#"[\[\]:`\{\}#'";\(\)\|\$,\d\s]|(?i)^[+\-]?(inf(inity)?|nan)$"#)
+        .expect("internal error: NEEDS_QUOTING_REGEX didn't compile")
+});
+
+pub fn needs_quoting(string: &str) -> bool {
+    if string.is_empty() {
+        return true;
+    }
+    // These are case-sensitive keywords
+    match string {
+        // `true`/`false`/`null` are active keywords in JSON and NUON
+        // `&&` is denied by the nu parser for diagnostics reasons
+        // (https://github.com/nushell/nushell/pull/7241)
+        "true" | "false" | "null" | "&&" => return true,
+        _ => (),
+    };
+    // All other cases are handled here
+    NEEDS_QUOTING_REGEX.is_match(string).unwrap_or(false)
+}
+
+pub fn escape_quote_string(string: &str) -> String {
+    let mut output = String::with_capacity(string.len() + 2);
+    output.push('"');
+
+    for c in string.chars() {
+        if c == '"' || c == '\\' {
+            output.push('\\');
+        }
+        output.push(c);
+    }
+
+    output.push('"');
+    output
+}

crates/nuon/Cargo.toml

@@ -13,8 +13,7 @@ version = "0.99.2"
 nu-parser = { path = "../nu-parser", version = "0.99.2" }
 nu-protocol = { path = "../nu-protocol", version = "0.99.2" }
 nu-engine = { path = "../nu-engine", version = "0.99.2" }
-once_cell = { workspace = true }
-fancy-regex = { workspace = true }
+nu-utils = { path = "../nu-utils", version = "0.99.2" }
 
 [dev-dependencies]
 chrono = { workspace = true }

crates/nuon/src/to.rs

@@ -1,10 +1,8 @@
 use core::fmt::Write;
-use fancy_regex::Regex;
-use once_cell::sync::Lazy;
 
 use nu_engine::get_columns;
-use nu_parser::escape_quote_string;
 use nu_protocol::{Range, ShellError, Span, Value};
+use nu_utils::{escape_quote_string, needs_quoting};
 
 use std::ops::Bound;
 
@@ -129,11 +127,12 @@ fn value_to_string(
                 let headers: Vec<String> = headers
                     .iter()
                     .map(|string| {
-                        if needs_quotes(string) {
-                            format!("{idt}\"{string}\"")
+                        let string = if needs_quoting(string) {
+                            &escape_quote_string(string)
                         } else {
+                            string
+                        };
                         format!("{idt}{string}")
-                        }
                     })
                     .collect();
                 let headers_output = headers.join(&format!(",{sep}{nl}{idt_pt}"));
@@ -199,19 +198,15 @@ fn value_to_string(
         Value::Record { val, .. } => {
             let mut collection = vec![];
             for (col, val) in &**val {
-                collection.push(if needs_quotes(col) {
-                    format!(
-                        "{idt_po}\"{}\": {}",
-                        col,
-                        value_to_string_without_quotes(val, span, depth + 1, indent)?
-                    )
+                let col = if needs_quoting(col) {
+                    &escape_quote_string(col)
                 } else {
-                    format!(
-                        "{idt_po}{}: {}",
-                        col,
+                    col
+                };
+                collection.push(format!(
+                    "{idt_po}{col}: {}",
                     value_to_string_without_quotes(val, span, depth + 1, indent)?
-                    )
-                });
+                ));
             }
             Ok(format!(
                 "{{{nl}{}{nl}{idt}}}",
@@ -247,7 +242,7 @@ fn value_to_string_without_quotes(
 ) -> Result<String, ShellError> {
     match v {
         Value::String { val, .. } => Ok({
-            if needs_quotes(val) {
+            if needs_quoting(val) {
                 escape_quote_string(val)
             } else {
                 val.clone()
@@ -256,30 +251,3 @@ fn value_to_string_without_quotes(
         _ => value_to_string(v, span, depth, indent),
     }
 }
-
-// This hits, in order:
-// • Any character of []:`{}#'";()|$,
-// • Any digit (\d)
-// • Any whitespace (\s)
-// • Case-insensitive sign-insensitive float "keywords" inf, infinity and nan.
-static NEEDS_QUOTES_REGEX: Lazy<Regex> = Lazy::new(|| {
-    Regex::new(r#"[\[\]:`\{\}#'";\(\)\|\$,\d\s]|(?i)^[+\-]?(inf(inity)?|nan)$"#)
-        .expect("internal error: NEEDS_QUOTES_REGEX didn't compile")
-});
-
-fn needs_quotes(string: &str) -> bool {
-    if string.is_empty() {
-        return true;
-    }
-    // These are case-sensitive keywords
-    match string {
-        // `true`/`false`/`null` are active keywords in JSON and NUON
-        // `&&` is denied by the nu parser for diagnostics reasons
-        // (https://github.com/nushell/nushell/pull/7241)
-        // TODO: remove the extra check in the nuon codepath
-        "true" | "false" | "null" | "&&" => return true,
-        _ => (),
-    };
-    // All other cases are handled here
-    NEEDS_QUOTES_REGEX.is_match(string).unwrap_or(false)
-}

src/command.rs

@@ -1,11 +1,11 @@
 use nu_engine::{command_prelude::*, get_full_help};
-use nu_parser::{escape_for_script_arg, escape_quote_string, parse};
+use nu_parser::{escape_for_script_arg, parse};
 use nu_protocol::{
     ast::{Expr, Expression},
     engine::StateWorkingSet,
     report_parse_error,
 };
-use nu_utils::stdout_write_all_and_flush;
+use nu_utils::{escape_quote_string, stdout_write_all_and_flush};
 
 pub(crate) fn gather_commandline_args() -> (Vec<String>, String, Vec<String>) {
     // Would be nice if we had a way to parse this. The first flags we see will be going to nushell