feat(terminal): configurable shell for bash tool (port upstream PR #260)

crates/jcode-config-types/src/lib.rs

@@ -892,3 +892,17 @@ impl Default for GatewayConfig {
         }
     }
 }
+
+/// Terminal / shell execution configuration (issue #260 follow-up).
+///
+/// When `shell` is set, the bash tool spawns the named shell instead
+/// of the platform default (`bash` on Unix, `cmd.exe` on Windows).
+/// Useful for users on `nu`, `zsh`, `fish`, or PowerShell who want
+/// shell-specific syntax to work in agent-spawned commands.
+///
+/// Overridden by the `JCODE_SHELL` env var.
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[serde(default)]
+pub struct TerminalConfig {
+    pub shell: Option<String>,
+}

src/config.rs

@@ -9,7 +9,8 @@ pub use jcode_config_types::{
     DiffDisplayMode, DisplayConfig, FeatureConfig, GatewayConfig, KeybindingsConfig,
     MarkdownSpacingMode, NamedProviderAuth, NamedProviderConfig, NamedProviderModelConfig,
     NamedProviderType, NativeScrollbarConfig, ProviderConfig, SafetyConfig,
-    SessionPickerResumeAction, SwarmSpawnMode, UpdateChannel, WebSearchConfig, WebSearchEngine,
+    SessionPickerResumeAction, SwarmSpawnMode, TerminalConfig, UpdateChannel, WebSearchConfig,
+    WebSearchEngine,
 };
 use serde::{Deserialize, Serialize};
 use std::collections::{BTreeMap, BTreeSet, HashSet};
@@ -104,6 +105,7 @@ const CONFIG_ENV_KEYS: &[&str] = &[
     "JCODE_SCROLL_PROMPT_UP_KEY",
     "JCODE_SCROLL_UP_FALLBACK_KEY",
     "JCODE_SCROLL_UP_KEY",
+    "JCODE_SHELL",
     "JCODE_SHOW_DIFFS",
     "JCODE_SHOW_THINKING",
     "JCODE_SIDE_PANEL_NATIVE_SCROLLBAR",
@@ -383,6 +385,9 @@ pub struct Config {
 
     /// Auto-judge configuration
     pub autojudge: AutoJudgeConfig,
+
+    /// Terminal / shell execution configuration (issue #260)
+    pub terminal: TerminalConfig,
 }
 
 /// Agent Client Protocol adapter configuration.

src/config/env_overrides.rs

@@ -441,6 +441,15 @@ impl Config {
             }
         }
 
+        // Terminal (issue #260 follow-up): JCODE_SHELL overrides
+        // the bash tool's default shell selection.
+        if let Ok(v) = std::env::var("JCODE_SHELL") {
+            let trimmed = v.trim().to_string();
+            if !trimmed.is_empty() {
+                self.terminal.shell = Some(trimmed);
+            }
+        }
+
         // Provider
         if let Ok(v) = std::env::var("JCODE_MODEL") {
             self.provider.default_model = Some(v);

src/tool/bash.rs

@@ -428,7 +428,23 @@ async fn handle_background_output_line(
     file.flush().await.ok();
 }
 
-fn build_shell_command(cmd_str: &str) -> TokioCommand {
+fn build_shell_command(shell: Option<&str>, cmd_str: &str) -> TokioCommand {
+    // Issue #260 follow-up: when the user configured a custom shell
+    // via `[terminal] shell = "..."` or JCODE_SHELL, just spawn that
+    // shell directly with the command string. The shell handles its
+    // own arg parsing (most shells accept `-c` for inline commands;
+    // PowerShell uses `-Command`; nu uses `-c`). Falls back to the
+    // platform default when shell is None.
+    if let Some(shell_name) = shell {
+        let mut cmd = TokioCommand::new(shell_name);
+        // Use `-c` as a reasonable default. Shells that don't accept
+        // it (e.g. fish-only) should be configured at the script
+        // level. PowerShell users should set shell = "pwsh" and the
+        // tool's input will be POSIX-shell-like; for full PowerShell
+        // syntax, wrap in `pwsh -Command` at the input level.
+        cmd.arg("-c").arg(cmd_str);
+        return cmd;
+    }
     #[cfg(windows)]
     {
         let mut cmd = TokioCommand::new("cmd.exe");
@@ -488,7 +504,7 @@ mod utf8_truncation_tests {
     #[cfg(windows)]
     #[tokio::test]
     async fn build_shell_command_uses_cmd_and_executes_command() {
-        let output = build_shell_command("echo hello-from-cmd")
+        let output = build_shell_command(None, "echo hello-from-cmd")
             .output()
             .await
             .expect("run cmd command");
@@ -627,7 +643,10 @@ impl BashTool {
 
         let has_stdin_channel = ctx.stdin_request_tx.is_some();
 
-        let mut command = build_shell_command(&params.command);
+        let mut command = build_shell_command(
+            crate::config::config().terminal.shell.as_deref(),
+            &params.command,
+        );
         command
             .kill_on_drop(true)
             .stdout(Stdio::piped())
@@ -900,7 +919,7 @@ impl BashTool {
                 notify,
                 wake,
 				move |output_path| async move {
-					let mut cmd = build_shell_command(&command);
+					let mut cmd = build_shell_command(crate::config::config().terminal.shell.as_deref(), &command);
 					#[cfg(unix)]
 					unsafe {
 						cmd.pre_exec(|| {