Invert &Options to Option<&T> (#10315)

Elide the reference for `Copy` type (`usize`)
Use the canonical deref where possible.
* `&Box` -> `&`
* `&String` -> `&str`
* `&PathBuf` -> `&Path`

Skips the ctrl-C handler for now.

crates/nu-plugin/src/plugin/declaration.rs

@@ -66,7 +66,7 @@ impl Command for PluginDeclaration {
         // Decode information from plugin
         // Create PipelineData
         let source_file = Path::new(&self.filename);
-        let mut plugin_cmd = create_command(source_file, &self.shell);
+        let mut plugin_cmd = create_command(source_file, self.shell.as_deref());
         // We need the current environment variables for `python` based plugins
         // Or we'll likely have a problem when a plugin is implemented in a virtual Python environment.
         let current_envs = nu_engine::env::env_to_strings(engine_state, stack).unwrap_or_default();
@@ -175,7 +175,7 @@ impl Command for PluginDeclaration {
         pipeline_data
     }
 
-    fn is_plugin(&self) -> Option<(&PathBuf, &Option<PathBuf>)> {
-        Some((&self.filename, &self.shell))
+    fn is_plugin(&self) -> Option<(&Path, Option<&Path>)> {
+        Some((&self.filename, self.shell.as_deref()))
     }
 }

crates/nu-plugin/src/plugin/mod.rs

@@ -8,7 +8,7 @@ use crate::EncodingType;
 use std::env;
 use std::fmt::Write;
 use std::io::{BufReader, ErrorKind, Read, Write as WriteTrait};
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use std::process::{Child, ChildStdout, Command as CommandSys, Stdio};
 
 use nu_protocol::{CustomValue, PluginSignature, ShellError, Span, Value};
@@ -48,7 +48,7 @@ pub trait PluginEncoder: Clone {
     ) -> Result<PluginResponse, ShellError>;
 }
 
-pub(crate) fn create_command(path: &Path, shell: &Option<PathBuf>) -> CommandSys {
+pub(crate) fn create_command(path: &Path, shell: Option<&Path>) -> CommandSys {
     let mut process = match (path.extension(), shell) {
         (_, Some(shell)) => {
             let mut process = std::process::Command::new(shell);
@@ -124,7 +124,7 @@ pub(crate) fn call_plugin(
 #[doc(hidden)] // Note: not for plugin authors / only used in nu-parser
 pub fn get_signature(
     path: &Path,
-    shell: &Option<PathBuf>,
+    shell: Option<&Path>,
     current_envs: &HashMap<String, String>,
 ) -> Result<Vec<PluginSignature>, ShellError> {
     let mut plugin_cmd = create_command(path, shell);

crates/nu-plugin/src/protocol/plugin_custom_value.rs

@@ -45,7 +45,7 @@ impl CustomValue for PluginCustomValue {
         &self,
         span: nu_protocol::Span,
     ) -> Result<nu_protocol::Value, nu_protocol::ShellError> {
-        let mut plugin_cmd = create_command(&self.filename, &self.shell);
+        let mut plugin_cmd = create_command(&self.filename, self.shell.as_deref());
 
         let mut child = plugin_cmd.spawn().map_err(|err| {
             ShellError::GenericError(