Avoid taking unnecessary ownership of intermediates (#12740)

# Description

Judiciously try to avoid allocations/clone by changing the signature of
functions

- **Don't pass str by value unnecessarily if only read**
- **Don't require a vec in `Sandbox::with_files`**
- **Remove unnecessary string clone**
- **Fixup unnecessary borrow**
- **Use `&str` in shape color instead**
- **Vec -> Slice**
- **Elide string clone**
- **Elide `Path` clone**
- **Take &str to elide clone in tests**

# User-Facing Changes
None

# Tests + Formatting
This touches many tests purely in changing from owned to borrowed/static
data

crates/nu-command/src/conversions/into/datetime.rs

@@ -39,7 +39,7 @@ impl Zone {
             Self::Error // Out of range
         }
     }
-    fn from_string(s: String) -> Self {
+    fn from_string(s: &str) -> Self {
         match s.to_ascii_lowercase().as_str() {
             "utc" | "u" => Self::Utc,
             "local" | "l" => Self::Local,
@@ -126,7 +126,7 @@ impl Command for SubCommand {
                         span: zone_offset.span,
                     }),
                     None => timezone.as_ref().map(|zone| Spanned {
-                        item: Zone::from_string(zone.item.clone()),
+                        item: Zone::from_string(&zone.item),
                         span: zone.span,
                     }),
                 };

crates/nu-command/src/env/config/config_env.rs

@@ -57,7 +57,7 @@ impl Command for ConfigEnv {
 
         let env_vars_str = env_to_strings(engine_state, stack)?;
         let nu_config = match engine_state.get_config_path("env-path") {
-            Some(path) => path.clone(),
+            Some(path) => path,
             None => {
                 return Err(ShellError::GenericError {
                     error: "Could not find $nu.env-path".into(),

crates/nu-command/src/env/config/config_nu.rs

@@ -61,7 +61,7 @@ impl Command for ConfigNu {
 
         let env_vars_str = env_to_strings(engine_state, stack)?;
         let nu_config = match engine_state.get_config_path("config-path") {
-            Some(path) => path.clone(),
+            Some(path) => path,
             None => {
                 return Err(ShellError::GenericError {
                     error: "Could not find $nu.config-path".into(),

crates/nu-command/src/env/config/utils.rs

@@ -1,10 +1,10 @@
 use crate::ExternalCommand;
 use nu_protocol::{OutDest, Span, Spanned};
-use std::{collections::HashMap, path::PathBuf};
+use std::{collections::HashMap, path::Path};
 
 pub(crate) fn gen_command(
     span: Span,
-    config_path: PathBuf,
+    config_path: &Path,
     item: String,
     config_args: Vec<String>,
     env_vars_str: HashMap<String, String>,

crates/nu-command/src/formats/from/xml.rs

@@ -197,15 +197,15 @@ fn from_document_to_value(d: &roxmltree::Document, info: &ParsingInfo) -> Value
     element_to_value(&d.root_element(), info)
 }
 
-fn from_xml_string_to_value(s: String, info: &ParsingInfo) -> Result<Value, roxmltree::Error> {
-    let parsed = roxmltree::Document::parse(&s)?;
+fn from_xml_string_to_value(s: &str, info: &ParsingInfo) -> Result<Value, roxmltree::Error> {
+    let parsed = roxmltree::Document::parse(s)?;
     Ok(from_document_to_value(&parsed, info))
 }
 
 fn from_xml(input: PipelineData, info: &ParsingInfo) -> Result<PipelineData, ShellError> {
     let (concat_string, span, metadata) = input.collect_string_strict(info.span)?;
 
-    match from_xml_string_to_value(concat_string, info) {
+    match from_xml_string_to_value(&concat_string, info) {
         Ok(x) => Ok(x.into_pipeline_data_with_metadata(metadata)),
         Err(err) => Err(process_xml_parse_error(err, span)),
     }
@@ -370,7 +370,7 @@ mod tests {
             keep_comments: false,
             keep_processing_instructions: false,
         };
-        from_xml_string_to_value(xml.to_string(), &info)
+        from_xml_string_to_value(xml, &info)
     }
 
     #[test]

crates/nu-command/src/formats/from/yaml.rs

@@ -185,14 +185,10 @@ fn convert_yaml_value_to_nu_value(
     })
 }
 
-pub fn from_yaml_string_to_value(
-    s: String,
-    span: Span,
-    val_span: Span,
-) -> Result<Value, ShellError> {
+pub fn from_yaml_string_to_value(s: &str, span: Span, val_span: Span) -> Result<Value, ShellError> {
     let mut documents = vec![];
 
-    for document in serde_yaml::Deserializer::from_str(&s) {
+    for document in serde_yaml::Deserializer::from_str(s) {
         let v: serde_yaml::Value =
             serde_yaml::Value::deserialize(document).map_err(|x| ShellError::UnsupportedInput {
                 msg: format!("Could not load YAML: {x}"),
@@ -238,7 +234,7 @@ pub fn get_examples() -> Vec<Example<'static>> {
 fn from_yaml(input: PipelineData, head: Span) -> Result<PipelineData, ShellError> {
     let (concat_string, span, metadata) = input.collect_string_strict(head)?;
 
-    match from_yaml_string_to_value(concat_string, head, span) {
+    match from_yaml_string_to_value(&concat_string, head, span) {
         Ok(x) => Ok(x.into_pipeline_data_with_metadata(metadata)),
         Err(other) => Err(other),
     }
@@ -274,11 +270,7 @@ mod test {
         ];
         let config = Config::default();
         for tc in tt {
-            let actual = from_yaml_string_to_value(
-                tc.input.to_owned(),
-                Span::test_data(),
-                Span::test_data(),
-            );
+            let actual = from_yaml_string_to_value(tc.input, Span::test_data(), Span::test_data());
             if actual.is_err() {
                 assert!(
                     tc.expected.is_err(),
@@ -313,11 +305,7 @@ mod test {
         // table was non-deterministic. It would take a few executions of the YAML conversion to
         // see this ordering difference. This loop should be far more than enough to catch a regression.
         for ii in 1..1000 {
-            let actual = from_yaml_string_to_value(
-                String::from(test_yaml),
-                Span::test_data(),
-                Span::test_data(),
-            );
+            let actual = from_yaml_string_to_value(test_yaml, Span::test_data(), Span::test_data());
 
             let expected: Result<Value, ShellError> = Ok(Value::test_list(vec![
                 Value::test_record(record! {