Fallback to available shell when run_terminal_command shell is missing

[siewcapital]

Summary

• make the terminal tool choose the first available Unix shell from SHELL, /bin/bash, /bin/sh, and /bin/ash
• avoid hard-failing when SHELL points to a missing path or /bin/bash is not installed
• add a regression test that verifies command execution still succeeds when SHELL is invalid

Why

In remote/devcontainer setups, some environments do not expose the expected shell path. Falling back to an available shell prevents spawn ... ENOENT failures and keeps terminal tooling usable.

Closes #11129

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Summary by cubic

Gracefully fall back to an available Unix shell in runTerminalCommand when SHELL is invalid or /bin/bash is missing, preventing spawn ENOENT errors in remote/devcontainer environments. Fixes #11129.

• Bug Fixes
  • Select the first available shell from $SHELL, /bin/bash, /bin/sh, or /bin/ash (non-absolute shells are resolved via PATH).
  • Added a regression test to verify command execution succeeds when SHELL points to a missing path.

^{Written for commit e93cef3. Summary will update on new commits.}

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[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="core/tools/implementations/runTerminalCommand.vitest.ts">

<violation number="1" location="core/tools/implementations/runTerminalCommand.vitest.ts:162">
P1: Environment variable cleanup may leak SHELL state - assigning undefined to process.env creates string 'undefined'</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: Environment variable cleanup may leak SHELL state - assigning undefined to process.env creates string 'undefined'

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At core/tools/implementations/runTerminalCommand.vitest.ts, line 162:

<comment>Environment variable cleanup may leak SHELL state - assigning undefined to process.env creates string 'undefined'</comment>

<file context>
@@ -142,6 +142,27 @@ describe("runTerminalCommandImpl", () => {
+      expect(result[0].status).toBe("Command completed");
+      expect(result[0].content).toContain("fallback shell works");
+    } finally {
+      process.env.SHELL = originalShell;
+    }
+  });
</file context>