Fix safe-inputs `script:` runner always returning `{"stdout":"","stderr":""}` by Copilot · Pull Request #19493 · github/gh-aw

Copilot · 2026-03-04T03:15:54Z

Understand the bug: generateSafeInputJavaScriptToolScript generates a .cjs that only exports execute() but never calls it when run as subprocess
Fix generateSafeInputJavaScriptToolScript in pkg/workflow/safe_inputs_generator.go to add a require.main === module block that reads stdin, calls execute(), and writes JSON to stdout
Refactor main execution block to use async/await instead of Promise chaining
Move the main execution harness to actions/setup/js/safe-inputs-runner.cjs; generated scripts delegate via require('./safe-inputs-runner.cjs')(execute)
Add actions/setup/js/safe-inputs-runner.test.cjs with 4 Vitest tests (happy path, empty stdin, JSON parse error, execute error)
Update actions/setup/setup.sh to copy safe-inputs-runner.cjs to the safe-inputs directory
Update test in safe_inputs_generator_test.go to assert require('./safe-inputs-runner.cjs') delegation
Fix TS18046: catch (e) variable is unknown; use e instanceof Error ? e.message : String(e) guard
All tests pass: make fmt, TypeScript check, Vitest tests

Original prompt

This section details on the original issue you should resolve

<issue_title>Bug: safe-inputs with script: always returns {"stdout":"","stderr":""}</issue_title>
<issue_description># Bug: safe-inputs with script: always returns {"stdout":"","stderr":""}

Summary

A safe-inputs entry using the script: runner always produces {"stdout":"","stderr":""} when called, regardless of what the script does. The return value is never surfaced to the agent.

Steps to Reproduce

Define a safe-input with script::
safe-inputs:
  github-graphql:
    inputs:
      query:
        type: string
        required: true
      variables:
        type: string
        required: false
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    script: |
      const graphql = require('@octokit/graphql').graphql.defaults({
        headers: { authorization: `token ${process.env.GITHUB_TOKEN}` }
      });
      const vars = inputs.variables ? JSON.parse(inputs.variables) : {};
      const result = await graphql(inputs.query, vars);
      return result;
Call it from a workflow. The agent receives:
{"stdout":"","stderr":""}
What I Tried

Using return result (object)

Using console.log(JSON.stringify(result)) — no output in stdout

Simplified scripts (e.g. return { viewer: { login: "test" } }) — still empty

The same logic works fine with py: using print(json.dumps(...)) — the Python runner correctly captures stdout

Expected Behavior

The script: runner should:

Capture the return value and serialize it as the tool output as documented

Actual Behavior

Every script: safe-input returns {"stdout":"","stderr":""} unconditionally. The agent sees no data and has to assume defaults / skip logic that depended on the result.

Impact

Workflows that rely on script: for GitHub GraphQL queries (or any JS-based safe-input) silently fail. The only workaround is to rewrite the logic in Python using py: or use run: with shell commands, which is significantly less ergonomic for GraphQL/JSON workloads.

Environment

gh aw (github/gh-aw) — current version in use

Runner: GitHub Actions (AWF sandbox)
</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Bug: safe-inputs with script: always returns {"stdout":"","stderr":""} #19489

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.

✨ PR Review Safe Output Test - Run 22656026286

💥 [THE END] — Illustrated by Smoke Claude · ◷

… main execution block to generated .cjs files Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-03-04T04:50:50Z

@copilot use async await

…ion block Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-03-04T04:56:03Z

@copilot use async await

Done in db05438. The stdin.on("end", ...) callback is now async and uses await execute(inputs) with a try/catch instead of Promise chaining.

pelikhan · 2026-03-04T05:00:16Z

@copilot move generated code to a separate file that gets required (safe-inputs-runner.cjs). Add tests , update setup.sh

…ests, update setup.sh Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-03-04T05:08:35Z

@copilot move generated code to a separate file that gets required (safe-inputs-runner.cjs). Add tests , update setup.sh

Done in b25a2c2. The main execution harness is now in actions/setup/js/safe-inputs-runner.cjs. Generated scripts just do require('./safe-inputs-runner.cjs')(execute) instead of inlining the stdin/stdout boilerplate. Added safe-inputs-runner.test.cjs with 4 Vitest tests (happy path, empty stdin, JSON parse error, execute error), and added the file to SAFE_INPUTS_FILES in setup.sh.

github-actions · 2026-03-04T05:10:10Z

📰 BREAKING: Smoke Copilot is now investigating this pull request. Sources say the story is developing...

github-actions · 2026-03-04T05:10:12Z

🎬 THE END — Smoke Claude MISSION: ACCOMPLISHED! The hero saves the day! ✨

github-actions · 2026-03-04T05:10:12Z

✅ All tools validated successfully! Agent Container Smoke Test confirms agent container is ready.

github-actions · 2026-03-04T05:10:17Z

🌑 The shadows whisper... Smoke Codex failed. The oracle requires further meditation...

github-actions · 2026-03-04T05:13:02Z

Commit pushed: 9027415

Generated by Changeset Generator

github-actions · 2026-03-04T05:13:07Z

Agent Container Tool Check

Tool	Status	Version
bash	✅	5.2.21
sh	✅	available
git	✅	2.53.0
jq	✅	1.7
yq	✅	4.52.4
curl	✅	8.5.0
gh	✅	2.87.3
node	✅	20.20.0
python3	✅	3.12.3
go	✅	1.24.13
java	✅	available (proxy settings detected)
dotnet	✅	10.0.102

Result: 12/12 tools available ✅

Overall Status: PASS

🔧 Tool validation by Agent Container Smoke Test · ◷

github-actions · 2026-03-04T05:15:20Z

Smoke test by @Copilot ✅/❌:

✅ GitHub MCP, Safe Inputs GH CLI, Playwright, Web Fetch, File Write, Bash, Discussion, Build, Discussion Create, Workflow Dispatch, PR Review
❌ Serena MCP (tools not available)

Overall: ⚠️ PARTIAL PASS — cc @pelikhan @Copilot

📰 BREAKING: Report filed by Smoke Copilot · ◷

github-actions

Fix looks correct — the root cause (generated scripts never writing to stdout) is properly addressed by extracting the runner into a shared module. The require.main === module guard is the right pattern. Two minor suggestions: add a timeout guard in the runner, and enhance the generated comment to explain the stdin/stdout protocol.

📰 BREAKING: Report filed by Smoke Copilot

github-actions · 2026-03-04T05:15:21Z

actions/setup/js/safe-inputs-runner.cjs

+    try {
+      const result = await execute(inputs);
+      process.stdout.write(JSON.stringify(result));
+    } catch (err) {


Consider adding a timeout to the stdin read to prevent hanging if the parent process closes the pipe unexpectedly. Something like process.stdin.resume() with a watchdog timer could guard against zombie processes.

github-actions · 2026-03-04T05:15:21Z

pkg/workflow/safe_inputs_generator.go

+	sb.WriteString("// Run when executed directly (as a subprocess by the MCP handler)\n")
+	sb.WriteString("if (require.main === module) {\n")
+	sb.WriteString("  require(\"./safe-inputs-runner.cjs\")(execute);\n")
+	sb.WriteString("}\n")


The generated comment // Run when executed directly (as a subprocess by the MCP handler) is helpful. Consider also noting why this pattern is needed (the MCP handler spawns the script as a subprocess and communicates via stdin/stdout), which would make the generated code self-documenting for anyone reading it.

github-actions · 2026-03-04T05:15:34Z

📰 VERDICT: Smoke Copilot has concluded. All systems operational. This is a developing story. 🎤

github-actions · 2026-03-04T05:19:10Z

Smoke Test Results - Run §22656026286

Core tests (#1–10): ⚠️ ✅ ❌ ✅ ✅ ✅ ✅ ✅ ✅ ✅
PR review tests (#11–17): ✅ ✅ ✅ ⚠️ ✅ ✅ ⚠️

Overall: PARTIAL

❌ Add workflow: githubnext/agentics/weekly-research #3 Serena find_symbol — EOF (MCP connection closed after activate_project)
⚠️ rejig docs #1 GitHub MCP response too large (71k tokens); fell back to gh CLI
⚠️ codex naming #14 No review threads to resolve
⚠️ Enhance timestamp and token usage extraction for Codex format in logs #17 No safe PR to close

💥 [THE END] — Illustrated by Smoke Claude · ◷

github-actions

💥 Automated smoke test review - all systems nominal! The safe-inputs runner refactor looks clean — shared module pattern reduces duplication and the tests cover all edge cases.

💥 [THE END] — Illustrated by Smoke Claude

pelikhan · 2026-03-04T05:20:17Z

@copilot fix test

CI / js (pull_request)Failing after 23s
CI / js-integration-live-api (pull_request)

github-actions · 2026-03-04T05:21:01Z

Hey @Copilot 👋 — great work tracking down this bug in the safe-inputs script: runner! The root cause (the generated .cjs file never invoking execute as a subprocess entry point) is clearly identified, and the fix is clean and well-structured.

This PR looks well-aligned with the project's contribution guidelines and code quality standards. Here's a quick summary of what looks great:

✅ Focused — single, coherent bug fix across exactly the right files
✅ Well described — detailed PR body with before/after code, runner logic, and link to the originating issue (Bug: safe-inputs with script: always returns {"stdout":"","stderr":""} #19489)
✅ Tests included — both Vitest tests for the new safe-inputs-runner.cjs and updated Go assertions in safe_inputs_generator_test.go
✅ Changeset added — .changeset/patch-safe-inputs-runner.md is present
✅ setup.sh updated — safe-inputs-runner.cjs correctly added to SAFE_INPUTS_FILES
✅ Process followed — community issue filed by @srgibbs99, picked up by a core team member (@pelikhan) and implemented via the Copilot coding agent

The PR is currently in draft state — once any remaining CI checks pass and the draft is marked ready, this looks well-positioned for maintainer review. 🚀

Generated by Contribution Check · ◷

…puts-runner.cjs Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot · 2026-03-04T05:24:31Z

@copilot fix test

CI / js (pull_request)Failing after 23s
...

Fixed in 6116f5c. The TypeScript error TS18046: 'e' is of type 'unknown' was caused by accessing .message directly on a catch variable. Changed to e instanceof Error ? e.message : String(e).

Copilot

Pull request overview

Fixes safe-inputs JavaScript script: tools always returning empty {"stdout":"","stderr":""} by ensuring generated scripts actually execute when run as a subprocess, via a shared runner harness.

Changes:

Update JS safe-input tool script generation to include a require.main === module entrypoint that delegates subprocess execution to a shared runner.
Add actions/setup/js/safe-inputs-runner.cjs and Vitest coverage for stdin parsing, parse errors, and execute errors.
Update setup packaging to copy the new runner into /opt/gh-aw/safe-inputs and add a changeset entry.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/workflow/safe_inputs_generator.go	Generated JS safe-input scripts now delegate subprocess execution to `safe-inputs-runner.cjs`.
pkg/workflow/safe_inputs_generator_test.go	Extends generator test to assert the new subprocess entrypoint + delegation.
actions/setup/js/safe-inputs-runner.cjs	New shared Node subprocess harness: reads stdin JSON, calls `execute`, writes JSON to stdout.
actions/setup/js/safe-inputs-runner.test.cjs	New Vitest coverage for the runner’s stdin parsing and error paths.
actions/setup/setup.sh	Ensures `safe-inputs-runner.cjs` is copied into the safe-inputs runtime directory.
.changeset/patch-safe-inputs-runner.md	Declares a patch release note for the safe-inputs runner fix.

Comments suppressed due to low confidence (2)

actions/setup/js/safe-inputs-runner.cjs:37

After JSON.parse, inputs can be a non-object (null/array/primitive) if a caller sends unexpected JSON. The generated scripts/JSDoc assume an object, and downstream destructuring/logic may behave incorrectly. Consider normalizing parsed values so only plain objects are passed to execute (e.g., if parsed value is not a non-array object, fall back to {}).

    let inputs = {};
    try {
      if (inputJson.trim()) {
        inputs = JSON.parse(inputJson.trim());
      }

actions/setup/js/safe-inputs-runner.cjs:47

On execute failure, the runner writes String(err) and immediately calls process.exit(1). String(err) can produce unhelpful output (e.g., [object Object]) and omits stack traces for Error objects, and an immediate process.exit can truncate pending stderr writes. Consider formatting errors similarly to the rest of the codebase (message + optional stack, newline-terminated) and setting process.exitCode = 1 (or exiting in the write callback) to ensure the error output is flushed before termination.

    } catch (err) {
      process.stderr.write(String(err));
      process.exit(1);
    }

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.

Initial plan

037585e

Copilot AI assigned Copilot and pelikhan Mar 4, 2026

Copilot started work on behalf of pelikhan March 4, 2026 03:15 View session

Fix: safe-inputs script: runner always returns empty stdout by adding…

9b20b04

… main execution block to generated .cjs files Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix safe-inputs to correctly return stdout and stderr~~ Fix safe-inputs script: runner always returning {"stdout":"","stderr":""} Mar 4, 2026

Copilot finished work on behalf of pelikhan March 4, 2026 03:37

Copilot started work on behalf of pelikhan March 4, 2026 04:50 View session

Refactor: use async/await in generated safe-inputs script main execut…

db05438

…ion block Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan March 4, 2026 04:56

Copilot started work on behalf of pelikhan March 4, 2026 05:00 View session

Refactor: move safe-inputs JS runner to safe-inputs-runner.cjs, add t…

b25a2c2

…ests, update setup.sh Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan March 4, 2026 05:09

pelikhan added the smoke label Mar 4, 2026

Add changeset [skip-ci]

9027415

ci: trigger checks

16d72af

github-actions bot added smoke-copilot and removed smoke labels Mar 4, 2026

github-actions bot mentioned this pull request Mar 4, 2026

Smoke Test: Copilot - 22656026299 #19511

Closed

github-actions bot reviewed Mar 4, 2026

View reviewed changes

github-actions bot mentioned this pull request Mar 4, 2026

Smoke Test: Claude - 22656026286 #19512

Closed

github-actions bot reviewed Mar 4, 2026

View reviewed changes

Copilot started work on behalf of pelikhan March 4, 2026 05:20 View session

github-actions bot mentioned this pull request Mar 4, 2026

[Contribution Check Report] Contribution Check — 2026-03-04 #19513

Closed

Fix TS18046: use instanceof Error guard for catch variable in safe-in…

6116f5c

…puts-runner.cjs Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot finished work on behalf of pelikhan March 4, 2026 05:24

pelikhan marked this pull request as ready for review March 4, 2026 05:28

Copilot AI review requested due to automatic review settings March 4, 2026 05:28

Copilot started reviewing on behalf of pelikhan March 4, 2026 05:28 View session

Copilot AI reviewed Mar 4, 2026

View reviewed changes

Merge branch 'main' into copilot/fix-safe-inputs-script-error

cebabbd

pelikhan merged commit 567fee9 into main Mar 4, 2026
44 checks passed

pelikhan deleted the copilot/fix-safe-inputs-script-error branch March 4, 2026 05:37

Conversation

Copilot AI commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Steps to Reproduce

What I Tried

Expected Behavior

Actual Behavior

Impact

Environment

Comments on the Issue (you are @copilot in this section)

Uh oh!

pelikhan commented Mar 4, 2026

Uh oh!

Copilot AI commented Mar 4, 2026

Uh oh!

pelikhan commented Mar 4, 2026

Uh oh!

Copilot AI commented Mar 4, 2026

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

github-actions bot commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

github-actions bot commented Mar 4, 2026

Agent Container Tool Check

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

github-actions bot left a comment

Choose a reason for hiding this comment

Uh oh!

github-actions bot Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

github-actions bot Mar 4, 2026

Choose a reason for hiding this comment

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

github-actions bot left a comment

Choose a reason for hiding this comment

Uh oh!

pelikhan commented Mar 4, 2026

Uh oh!

github-actions bot commented Mar 4, 2026

Uh oh!

Copilot AI commented Mar 4, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Copilot AI commented Mar 4, 2026 •

edited

Loading

github-actions bot commented Mar 4, 2026 •

edited

Loading

github-actions bot commented Mar 4, 2026 •

edited

Loading

github-actions bot commented Mar 4, 2026 •

edited

Loading