[Repo Assist] refactor(guard): consolidate wazero interpreter runtime construction in tests by github-actions[bot] · Pull Request #11500 · github/gh-aw-mcpg

github-actions · 2026-08-19T13:02:35Z

🤖 This is an automated pull request from Repo Assist, an AI assistant for this repository.

Summary

Addresses a "Quick Win" suggested in #11491 (Go Fan module review of tetratelabs/wazero): consolidate the repeated wazero interpreter runtime construction scattered across guard test files into a single shared helper.

Rationale

wazero.NewRuntimeWithConfig(ctx, wazero.NewRuntimeConfigInterpreter()) was duplicated at 7 call sites across internal/guard/wasm_test.go, internal/guard/wasm_dispatch_test.go, and internal/guard/wasm_parse_coverage_test.go. Centralizing this into one helper reduces duplication and means any future test-runtime config change (e.g. adding a memory limit) is a one-line edit instead of a multi-file find-and-replace.

Changes

Added newTestInterpreterRuntime(ctx context.Context) wazero.Runtime in internal/guard/wasm_test.go.
Replaced all 7 call sites (across the three test files, all in package guard) with calls to the new helper.

Trade-offs

Purely mechanical, behavior-preserving change — no functional difference, since all call sites used identical config.
Left WithDebugInfoEnabled(false) and disk-backed compilation cache defaults (also suggested in [go-fan] Go Module Review: tetratelabs/wazero #11491) untouched, as those involve perf/behavior trade-offs better decided by a maintainer.

Test Status

go build ./... — ✅ succeeded
go test ./internal/guard/... — ✅ passed
gofmt -l internal/guard/ — ✅ no output (properly formatted)

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…in tests Add newTestInterpreterRuntime(ctx) helper in internal/guard/wasm_test.go and use it in place of the 7 repeated wazero.NewRuntimeWithConfig(ctx, wazero.NewRuntimeConfigInterpreter()) call sites across wasm_test.go, wasm_dispatch_test.go, and wasm_parse_coverage_test.go. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Consolidates test-only wazero interpreter runtime creation into a shared helper, reducing duplicated configuration without changing behavior.

Changes:

Adds newTestInterpreterRuntime.
Replaces all seven duplicated runtime constructions.

Show a summary per file

File	Description
`internal/guard/wasm_test.go`	Adds helper and updates five call sites.
`internal/guard/wasm_parse_coverage_test.go`	Uses shared runtime helper.
`internal/guard/wasm_dispatch_test.go`	Uses shared runtime helper.

Review details

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Files reviewed: 3/3 changed files
Comments generated: 0
Review effort level: Balanced

github-actions · 2026-08-19T14:42:20Z

🔒 mcpg Read-Only Stress — gVisor

Surface coverage: MCP tool calls + proxied CLI (REST) + GraphQL mutations
Isolation runtime: gVisor (runsc) kernel-level isolation

Part	Surface	Op	Result	Expected	Status
A	MCP	reads (list_issues / list_pull_requests / get_file_contents / list_commits)	data returned	ALLOWED	✅
B	MCP	writes (reaction/star/issue/comment/branch/file/PR)	tool absent	BLOCKED	⚠️
C	CLI	reads (list_issues / get_file_contents via `github` CLI)	data returned	ALLOWED	✅
D	CLI	REST writes	n/a	BLOCKED	⚠️
E	CLI	GraphQL mutations	n/a	BLOCKED	⚠️

Overall: INCONCLUSIVE

Notes

Part B — INCONCLUSIVE: All 7 targeted write tools (add_issue_comment, star_repository, issue_write, create_branch, create_or_update_file, create_pull_request) are absent from the MCP tool catalog (23 read-only tools exposed; all write attempts return Error [-32602]: unknown tool). This confirms the GITHUB_READ_ONLY=1 backend defense-in-depth guarantee holds under gVisor, but the gateway's own independent DIFC/guard write-blocking layer cannot be confirmed from this surface per the test plan's architectural note.

Parts D/E — INCONCLUSIVE: gh CLI is unauthenticated (GH_TOKEN not set). All REST/GraphQL write attempts would 401 due to missing credentials, not gateway enforcement. Token-scope boundary cannot be validated in this run.

No write leaked through the gateway. The INCONCLUSIVE result reflects methodology gaps (read-only backend + unauthenticated CLI), not enforcement failures.

References: §32255885257

🔒 mcpg read-only stress (gVisor runtime) by Read-Only Stress: gVisor runtime

github-actions · 2026-08-19T14:42:29Z

🔒 mcpg Read-Only Stress — docker-sbx

Surface coverage: MCP tool calls + proxied CLI (REST) + GraphQL mutations
Isolation runtime: docker-sbx (KVM-isolated microVM)

Part	Surface	Op	Result	Expected	Status
A	MCP	list_issues	3 issues returned	ALLOWED	✅
A	MCP	list_pull_requests	3 PRs returned	ALLOWED	✅
A	MCP	get_file_contents (README.md)	content returned	ALLOWED	✅
A	MCP	list_commits	3 commits returned	ALLOWED	✅
B	MCP	add_issue_comment (reaction)	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	star_repository	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	issue_write (create)	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	add_issue_comment (body)	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	create_branch	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	create_or_update_file	unknown tool [-32602]	BLOCKED	⚠️
B	MCP	create_pull_request	unknown tool [-32602]	BLOCKED	⚠️
C	CLI	list_issues	data returned	ALLOWED	✅
C	CLI	get_file_contents	data returned	ALLOWED	✅
D	CLI	REST writes (5 attempts)	401 Bad credentials	BLOCKED	⚠️
E	CLI	GraphQL mutations (3 attempts)	401 Bad credentials	BLOCKED	⚠️

Overall: INCONCLUSIVE

⚠️ Part B: All 7 write tools absent from the 23-tool catalog (GITHUB_READ_ONLY=1 backend config). Refusals are backend-config enforcement, not confirmed gateway-layer blocking. INCONCLUSIVE per methodology.

⚠️ Parts D/E: gh is unauthenticated in this environment (GH_TOKEN is invalid). All REST/GraphQL write attempts returned 401 Bad credentials — writes were not accepted, but this does not confirm token-scope boundary enforcement. INCONCLUSIVE per methodology.

References: §32255885314

🔒 mcpg read-only stress (docker-sbx runtime) by Read-Only Stress: docker-sbx runtime

github-actions · 2026-08-19T14:42:38Z

🔒 mcpg Read-Only Stress — default AWF

Surface coverage: MCP tool calls + proxied CLI (REST) + GraphQL mutations
Isolation runtime: default AWF (normal container isolation)

Part	Surface	Op	Result	Expected	Status
A	MCP	reads (issues/PRs/file/commits)	data returned	ALLOWED	✅
B	MCP	writes (reaction/star/issue/comment/branch/file/PR)	tool not found	BLOCKED	⚠️
C	CLI	reads (issues/file via github bridge)	data returned	ALLOWED	✅
D	CLI	REST writes (reaction/star/issue/comment/file)	unauthenticated	BLOCKED	⚠️
E	CLI	GraphQL mutations (addReaction/addStar/createIssue)	unauthenticated	BLOCKED	⚠️

Overall: INCONCLUSIVE

Part A: All MCP reads succeeded — list_issues, list_pull_requests, get_file_contents (README.md), and list_commits all returned data via the gateway MCP bridge. ✅

Part B: The exposed MCP tool catalog contains exactly 23 read-only tools (get_commit, get_file_contents, issue_read, list_, search_, pull_request_read, etc.). All 7 write tool attempts (add_issue_comment, star_repository, issue_write, create_branch, create_or_update_file, create_pull_request) returned Error [-32602]: unknown tool — confirming the backend launched with GITHUB_READ_ONLY=1. No write leaked. ⚠️ INCONCLUSIVE: write tools absent from catalog means gateway-level DIFC enforcement was not independently exercised (per test plan methodology — this is expected and noted, not a failure).

Part C: CLI reads via the gateway-backed github bridge succeeded. ✅

Parts D/E: ⚠️ gh CLI is not authenticated in this environment (GH_TOKEN not set). All REST write and GraphQL mutation attempts returned "not logged into any GitHub hosts" — the token-scope enforcement boundary cannot be validated in this run. This is an authentication gap, not a write leak.

No writes succeeded. INCONCLUSIVE due to: (1) write tools absent from MCP catalog (backend GITHUB_READ_ONLY=1 prevents gateway DIFC test), (2) gh unauthenticated (REST/GraphQL token-scope boundary not verifiable).

References: §32255885308

🔒 mcpg read-only stress (default AWF runtime) by Read-Only Stress: default runtime

github-actions Bot added automation refactor repo-assist labels Aug 19, 2026

lpcox marked this pull request as ready for review August 19, 2026 14:37

Copilot AI balanced review requested due to automatic review settings August 19, 2026 14:37

Copilot started reviewing on behalf of lpcox August 19, 2026 14:38 View session

Copilot AI reviewed Aug 19, 2026

View reviewed changes

github-actions Bot added the readonly-stress-pass-gvisor label Aug 19, 2026

github-actions Bot added the readonly-stress-pass-default label Aug 19, 2026

lpcox merged commit b9f26d3 into main Aug 19, 2026
35 checks passed

lpcox deleted the repo-assist/improve-wazero-test-helper-11491-2e440e79938ff12a branch August 19, 2026 14:48

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[Repo Assist] refactor(guard): consolidate wazero interpreter runtime construction in tests - #11500

[Repo Assist] refactor(guard): consolidate wazero interpreter runtime construction in tests#11500
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github-actions Bot commented Aug 19, 2026

🔒 mcpg Read-Only Stress — gVisor

Notes

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github-actions Bot commented Aug 19, 2026

🔒 mcpg Read-Only Stress — docker-sbx

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github-actions Bot commented Aug 19, 2026

🔒 mcpg Read-Only Stress — default AWF

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