Treat zsh -lc like bash -lc (#5411)

Without proper `zsh -lc` parsing, we lose some things like proper
command parsing, turn diff tracking, safe command checks, and other
things we expect from raw or `bash -lc` commands.

codex-rs/core/src/bash.rs

@@ -5,13 +5,13 @@ use tree_sitter_bash::LANGUAGE as BASH;
 
 /// Parse the provided bash source using tree-sitter-bash, returning a Tree on
 /// success or None if parsing failed.
-pub fn try_parse_bash(bash_lc_arg: &str) -> Option<Tree> {
+pub fn try_parse_shell(shell_lc_arg: &str) -> Option<Tree> {
     let lang = BASH.into();
     let mut parser = Parser::new();
     #[expect(clippy::expect_used)]
     parser.set_language(&lang).expect("load bash grammar");
     let old_tree: Option<&Tree> = None;
-    parser.parse(bash_lc_arg, old_tree)
+    parser.parse(shell_lc_arg, old_tree)
 }
 
 /// Parse a script which may contain multiple simple commands joined only by
@@ -88,18 +88,19 @@ pub fn try_parse_word_only_commands_sequence(tree: &Tree, src: &str) -> Option<V
     Some(commands)
 }
 
-/// Returns the sequence of plain commands within a `bash -lc "..."` invocation
-/// when the script only contains word-only commands joined by safe operators.
-pub fn parse_bash_lc_plain_commands(command: &[String]) -> Option<Vec<Vec<String>>> {
-    let [bash, flag, script] = command else {
+/// Returns the sequence of plain commands within a `bash -lc "..."` or
+/// `zsh -lc "..."` invocation when the script only contains word-only commands
+/// joined by safe operators.
+pub fn parse_shell_lc_plain_commands(command: &[String]) -> Option<Vec<Vec<String>>> {
+    let [shell, flag, script] = command else {
         return None;
     };
 
-    if bash != "bash" || flag != "-lc" {
+    if flag != "-lc" || !(shell == "bash" || shell == "zsh") {
         return None;
     }
 
-    let tree = try_parse_bash(script)?;
+    let tree = try_parse_shell(script)?;
     try_parse_word_only_commands_sequence(&tree, script)
 }
 
@@ -154,7 +155,7 @@ mod tests {
     use super::*;
 
     fn parse_seq(src: &str) -> Option<Vec<Vec<String>>> {
-        let tree = try_parse_bash(src)?;
+        let tree = try_parse_shell(src)?;
         try_parse_word_only_commands_sequence(&tree, src)
     }
 
@@ -234,4 +235,11 @@ mod tests {
     fn rejects_trailing_operator_parse_error() {
         assert!(parse_seq("ls &&").is_none());
     }
+
+    #[test]
+    fn parse_zsh_lc_plain_commands() {
+        let command = vec!["zsh".to_string(), "-lc".to_string(), "ls".to_string()];
+        let parsed = parse_shell_lc_plain_commands(&command).unwrap();
+        assert_eq!(parsed, vec![vec!["ls".to_string()]]);
+    }
 }