fix: allow piped bash commands through Copilot SDK permission checker by Copilot · Pull Request #37369 · github/gh-aw

Copilot · 2026-06-06T17:46:02Z

When the Copilot SDK sends a permission request for a piped/chained command (e.g. ls /tmp && cat file.json || echo "not found"), it sends commands: [] — an empty identifiers array. The original checker only tested commandIdentifiers.includes(rule), so every piped command was unconditionally denied, hitting the 5/5 denial threshold and killing the GEO Optimizer agent session.

Core fix — `copilot_sdk_driver.cjs`

Added a fallback path in isAllowed for the "shell" case: when commandIdentifiers is empty, parse fullCommandText via the new pipeline parser and require all pipeline stages to be individually permitted (every(), not some() — a disallowed stage anywhere in the chain still denies the whole command).

// Before: commandIdentifiers is [] for piped commands → always false → deny
commandIdentifiers.some(id => shellRules.includes(id))

// After: parse fullCommandText, check every stage
const names = extractCommandNamesFromPipeline(fullCommand);
if (names.length > 1) return names.every(isIdentifierAllowedByShellRules);

New parser — `bash_command_parser.cjs`

Dedicated state-machine parser that splits on &&, ||, |, ; while correctly handling single/double quotes and $(...) subshells. Exports:

splitOnPipelineOperators(text) — returns pipeline segments
extractCommandName(segment) — skips env-var assignments, redirections, shell keywords (then, fi, etc.), and negation (!)
extractCommandNamesFromPipeline(text) — deduplicated end-to-end

Runtime scope

This PR now targets the JavaScript runtime only. The previously added Python driver/runtime artifacts were removed because this repository does not maintain a Python runtime for this path.

Tests

File	Tests
`bash_command_parser.test.cjs`	90 unit tests — expanded extensive vector suite for all three exports, GEO optimizer failing commands, and additional AW-style parser edge cases
`fuzz_bash_command_parser_harness.test.cjs`	177 property/fuzz tests — exhaustive operator×command matrix, quote-protection and no-throw invariants
`copilot_sdk_driver.test.cjs`	+9 integration tests — piped command permission scenarios

- Add bash_command_parser.cjs: dedicated parser splitting on &&, ||, |, ; with quote and $() awareness - Update copilot_sdk_driver.cjs: fallback for empty commandIdentifiers uses pipeline parser so piped commands (e.g. ls && cat || echo) are allowed instead of denied - Add bash_command_parser.test.cjs: 55 unit tests - Add fuzz_bash_command_parser_harness.cjs: property-based fuzz harness - Add fuzz_bash_command_parser_harness.test.cjs: 177 property/fuzz tests - Update copilot_sdk_driver.test.cjs: 9 new integration tests for piped permission handling - Add bash_tool_compiler.py: Python implementation of the same bash pipeline parser and permission checker - Add test_bash_tool_compiler.py: 87 Python unittest+pytest tests Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

- copilot_sdk_driver.cjs: expand JSDoc on isIdentifierAllowedByShellRules to detail all three rule formats (wildcard :*, single-word, full-command) - bash_command_parser.cjs: expand SHELL_KEYWORDS comment explaining why keywords must be excluded from permission checking - fuzz_bash_command_parser_harness.test.cjs: extract nested flatMap/filter/map chain into generateCommandPairs helper - bash_tool_compiler.py: add note explaining why linear scan in is_identifier_allowed_by_shell_rules is acceptable Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

pelikhan · 2026-06-06T18:30:21Z

@copilot add extensive unit test suite for parser. Mine existing AW for patterns.

Copilot

Pull request overview

This PR fixes Copilot SDK permission-checking for chained/piped shell commands when the SDK provides an empty commands: [] identifiers list, by falling back to parsing fullCommandText and requiring every pipeline stage’s command name to be permitted.

Changes:

Added a bash pipeline parser (splitOnPipelineOperators, extractCommandName, extractCommandNamesFromPipeline) and used it as a fallback in the Node Copilot SDK permission handler.
Added comprehensive JS unit + fuzz/property tests covering pipeline splitting and command-name extraction.
Added a Python port of the parser and permission helpers with a matching test suite.

Show a summary per file

File	Description
actions/setup/js/copilot_sdk_driver.cjs	Adds pipeline-aware fallback permission logic for shell requests with missing SDK identifiers.
actions/setup/js/bash_command_parser.cjs	Introduces state-machine parsing for pipeline operators and command-name extraction.
actions/setup/js/copilot_sdk_driver.test.cjs	Adds integration tests for piped/chained command permission scenarios.
actions/setup/js/bash_command_parser.test.cjs	Adds unit tests for the new parser utilities.
actions/setup/js/fuzz_bash_command_parser_harness.cjs	Provides a structured harness for fuzz/property invariants (no-throw, quoted operators, safe defaults).
actions/setup/js/fuzz_bash_command_parser_harness.test.cjs	Adds vitest-based fuzz/property tests over operators/quoting matrices and invariants.
.github/drivers/bash_tool_compiler.py	Adds Python implementation of the parser + permission helpers for Python-based drivers.
.github/drivers/test_bash_tool_compiler.py	Adds a comprehensive Python unittest suite for the new Python parser/helpers.

Copilot's findings

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Files reviewed: 8/8 changed files
Comments generated: 6

+    // ── $(...) subshell: skip balanced parentheses as a unit ──
+    if (ch === "$" && i + 1 < len && commandText[i + 1] === "(") {
+      current += ch;
+      i++;
+      let depth = 0;
+      while (i < len) {
+        const sc = commandText[i];
+        if (sc === "(") depth++;
+        else if (sc === ")") {
+          depth--;
+          current += sc;
+          i++;
+          if (depth === 0) break;
+          continue;
+        }
+        current += sc;
+        i++;
+      }
+      continue;
+    }


+  // Skip leading env-var assignments: IDENTIFIER=anything  (repeat)
+  const envAssignRe = /^[A-Za-z_][A-Za-z0-9_]*=\S*\s*/;


+  it("handles nested $() subshells", () => {
+    const segments = splitOnPipelineOperators("echo $(echo $(ls && pwd)) && date");
+    expect(segments).toHaveLength(2);
+    expect(segments[0]).toContain("echo $(echo $(ls && pwd))");
+    expect(segments[1]).toContain("date");
+  });
+


+        # ── $(...) subshell: balanced parentheses ─────────────────────────
+        if ch == "$" and i + 1 < n and command_text[i + 1] == "(":
+            current.append(ch)
+            i += 1
+            depth = 0
+            while i < n:
+                sc = command_text[i]
+                if sc == "(":
+                    depth += 1
+                elif sc == ")":
+                    depth -= 1
+                    current.append(sc)
+                    i += 1
+                    if depth == 0:
+                        break
+                    continue
+                current.append(sc)
+                i += 1
+            continue


+# Regex to detect leading env-var assignment: WORD=anything
+_ENV_ASSIGN_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*=\S*")


+    names = extract_command_names_from_pipeline(command_text)
+    if not names:
+        return False
+    return all(is_identifier_allowed_by_shell_rules(name, shell_rules) for name in names)


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

Copilot · 2026-06-06T18:41:33Z

@copilot add extensive unit test suite for parser. Mine existing AW for patterns.

Added an extensive parser unit test vector suite in actions/setup/js/bash_command_parser.test.cjs (table-driven coverage for split, command extraction, and pipeline extraction cases) in commit cb2b14b.

pelikhan · 2026-06-06T18:48:20Z

@copilot merge main and recompile

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

Copilot · 2026-06-06T19:03:34Z

@copilot merge main and recompile

Done in 8a7249b: merged origin/main into this branch, resolved the merge conflict in actions/setup/js/copilot_sdk_driver.cjs, and recompiled actions (make actions-build).

pelikhan · 2026-06-06T19:16:49Z

@@ -0,0 +1,362 @@
+#!/usr/bin/env python3


@copilot delete this file. We are not maintaimimg a python runtime

Done in 424abea — removed .github/drivers/bash_tool_compiler.py and the related .github/drivers/test_bash_tool_compiler.py file.

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

Initial plan

3621db4

Copilot AI assigned Copilot and pelikhan Jun 6, 2026

Copilot started work on behalf of pelikhan June 6, 2026 17:46 View session

Copilot AI linked an issue Jun 6, 2026 that may be closed by this pull request

[aw] GEO Optimizer Daily Audit failed #37365

Closed

Copilot AI and others added 2 commits June 6, 2026 18:05

Copilot AI changed the title ~~[WIP] Fix GEO Optimizer Daily Audit workflow failure~~ fix: allow piped bash commands through Copilot SDK permission checker Jun 6, 2026

Copilot finished work on behalf of pelikhan June 6, 2026 18:09

Copilot AI requested a review from pelikhan June 6, 2026 18:09

pelikhan marked this pull request as ready for review June 6, 2026 18:29

Copilot AI review requested due to automatic review settings June 6, 2026 18:29

Copilot started reviewing on behalf of pelikhan June 6, 2026 18:29 View session

Copilot AI reviewed Jun 6, 2026

View reviewed changes

Copilot started work on behalf of pelikhan June 6, 2026 18:34 View session

test: expand bash parser unit test vectors

cb2b14b

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

Copilot finished work on behalf of pelikhan June 6, 2026 18:42

Copilot started work on behalf of pelikhan June 6, 2026 18:49 View session

github-actions Bot mentioned this pull request Jun 6, 2026

[aw] PR Sous Chef failed #37381

Closed

Merge origin/main and recompile actions

8a7249b

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

Copilot finished work on behalf of pelikhan June 6, 2026 19:03

pelikhan reviewed Jun 6, 2026

View reviewed changes

Copilot started work on behalf of pelikhan June 6, 2026 19:17 View session

chore: remove unused python bash compiler artifacts

424abea

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

Copilot finished work on behalf of pelikhan June 6, 2026 19:25

Copilot AI requested a review from pelikhan June 6, 2026 19:25

pelikhan merged commit 071e5ca into main Jun 6, 2026

pelikhan deleted the copilot/aw-fix-geo-optimizer-audit branch June 6, 2026 19:25

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fix: allow piped bash commands through Copilot SDK permission checker#37369

fix: allow piped bash commands through Copilot SDK permission checker#37369
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		// Skip leading env-var assignments: IDENTIFIER=anything (repeat)
		const envAssignRe = /^[A-Za-z_][A-Za-z0-9_]=\S\s*/;

		# Regex to detect leading env-var assignment: WORD=anything
		_ENV_ASSIGN_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]=\S")

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Copilot AI commented Jun 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Core fix — copilot_sdk_driver.cjs

New parser — bash_command_parser.cjs

Runtime scope

Tests

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Pull request overview

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Copilot AI commented Jun 6, 2026 •

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Core fix — `copilot_sdk_driver.cjs`

New parser — `bash_command_parser.cjs`