Add autofix review loop for Copilot PRs

.github/workflows/address-review.agent.md

@@ -0,0 +1,40 @@
+---
+name: "Address Review Comments"
+description: >-
+  Automatically addresses code review feedback on Copilot-created PRs.
+  Reads review comments, applies fixes, verifies the build, and pushes changes.
+  Includes a circuit breaker (max 3 iterations) to prevent infinite loops.
+
+on:
+  pull_request_review:
+    types: [submitted]
+  reaction: "eyes"
+
+# Only run when:
+# 1. The review explicitly requests changes (not an approval or informational comment)
+# 2. The PR is from the same repo (not a fork — we need push access)
+# 3. The PR was created by Copilot OR has the 'copilot-autofix' label
+if: >-
+  github.event.review.state == 'changes_requested'
+  && github.event.pull_request.head.repo.id == github.repository_id
+  && (
+    github.event.pull_request.user.login == 'copilot-swe-agent[bot]'
+    || contains(github.event.pull_request.labels.*.name, 'copilot-autofix')
+  )
+
+permissions:
+  contents: read
+  pull-requests: read
+  actions: read
+
+imports:
+  - shared/address-review-shared.md
+
+safe-outputs:
+  noop:
+    report-as-issue: false
+
+timeout-minutes: 60
+---
+
+<!-- Body provided by shared/address-review-shared.md -->

.github/workflows/autofix.agent.md

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+---
+name: "Address Review Comments (command)"
+description: >-
+  Addresses code review feedback when a maintainer comments /autofix on a PR.
+  Same behavior as the automatic address-review workflow but manually triggered.
+
+on:
+  slash_command:
+    name: autofix
+    events: [pull_request_comment]
+  roles: [admin, maintainer, write]
+  reaction: "eyes"
+
+permissions:
+  contents: read
+  pull-requests: read
+  actions: read
+
+imports:
+  - shared/address-review-shared.md
+
+safe-outputs:
+  noop:
+    report-as-issue: false
+
+timeout-minutes: 60
+---
+
+<!-- Body provided by shared/address-review-shared.md -->

.github/workflows/review-after-autofix.agent.md

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+---
+name: "Re-review After Autofix"
+description: >-
+  Re-runs the expert code review after new commits are pushed to a
+  Copilot-created PR. This closes the autofix loop: after the address-review
+  workflow pushes fixes, this workflow verifies them with the expert-reviewer.
+
+on:
+  pull_request:
+    types: [synchronize]
+
+# Only re-review when:
+# 1. The PR is not a draft
+# 2. The PR was created by Copilot OR has the 'copilot-autofix' label
+if: >-
+  github.event.pull_request.draft == false
+  && (
+    github.event.pull_request.user.login == 'copilot-swe-agent[bot]'
+    || contains(github.event.pull_request.labels.*.name, 'copilot-autofix')
+  )
+
+checkout: false
+
+permissions:
+  contents: read
+  pull-requests: read
+
+imports:
+  - shared/review-shared.md
+
+safe-outputs:
+  noop:
+    report-as-issue: false
+
+timeout-minutes: 60
+---
+
+<!-- Body provided by shared/review-shared.md -->

.github/workflows/shared/address-review-shared.md

@@ -0,0 +1,192 @@
+---
+# Shared configuration and body for the address-review workflows.
+#
+# Imported by address-review.agent.md (automatic trigger) and
+# autofix.agent.md (slash command). Keeps the fix logic in one place.
+
+description: "Shared configuration for address-review workflows"
+
+permissions:
+  contents: read
+  pull-requests: read
+  actions: read
+
+network:
+  allowed:
+    - defaults
+    - dotnet
+
+imports:
+  - shared/repo-build-setup.md
+
+tools:
+  github:
+    lockdown: true
+    toolsets: [pull_requests, repos]
+    min-integrity: none
+  edit:
+  bash: ["dotnet", "git", "find", "ls", "cat", "grep", "head", "tail", "wc", "mkdir", "sed"]
+
+safe-outputs:
+  push-to-pull-request-branch:
+    max: 3
+  add-comment:
+    max: 3
+    hide-older-comments: true
+  noop:
+    report-as-issue: false
+---
+
+# Address Review Comments
+
+You are an expert .NET developer working on the MSTest testing framework and
+Microsoft.Testing.Platform (MTP) repository. A pull request has received a code
+review with feedback. Your job is to read every review comment, assess whether it
+should be addressed, apply fixes where appropriate, explain your reasoning when
+skipping a suggestion, verify the build, and push the changes.
+
+## Context
+
+- **PR**: #${{ github.event.pull_request.number || github.event.issue.number }}
+- **Repository**: ${{ github.repository }}
+
+## Circuit Breaker — Check First
+
+Before making any code changes, determine how many autofix iterations have
+already run on this PR:
+
+1. List all comments on the PR.
+2. Count comments that contain the **exact** marker `<!-- autofix-iteration -->`.
+3. **If the count is 3 or more**, post the following comment and then **stop immediately** — do not edit any files:
+
+   > ⚠️ **Autofix loop limit reached** (3 iterations). This PR needs human attention.
+   > <!-- autofix-limit-reached -->
+
+   Then exit.
+
+## Step 1 — Understand the Review Feedback
+
+1. Fetch the full diff for the pull request.
+2. Fetch **all** review comments (inline and top-level) from the most recent
+   review.
+3. Read each comment carefully. Classify it as one of:
+   - **Blocking** — the reviewer explicitly requested a change (`REQUEST_CHANGES`
+     review, or language like "must", "should", "fix", "change").
+   - **Suggestion** — a non-blocking improvement idea ("consider", "nit",
+     "optional", "could", or posted under a `COMMENT` review).
+   - **Informational** — praise, acknowledgement, or context with no action asked.
+4. Identify the specific file and line(s) for each comment.
+5. Group related comments together (e.g., the same pattern flagged in multiple
+   files).
+
+If there are **no blocking or suggestion comments** (only informational or
+praise), post a short comment explaining there is nothing to address and exit.
+
+## Step 2 — Read Project Conventions
+
+Before editing code, read the following files to understand project conventions:
+
+- `.github/copilot-instructions.md` — coding standards, localization rules,
+  public API policy, and testing guidelines.
+- `.editorconfig` — formatting and naming rules.
+
+Apply these conventions to every change you make.
+
+## Step 3 — Assess and Apply Fixes
+
+For each review comment (or group of related comments), apply the following
+decision process:
+
+### Blocking comments → always fix
+
+1. Read the relevant source file(s) to understand context.
+2. Apply the requested change precisely.
+3. If the review flags a **pattern** (e.g., missing `ConfigureAwait(false)`,
+   wrong naming convention), search for the same pattern in **other files
+   touched by the PR** and fix those occurrences too.
+4. Keep changes minimal — only fix what was flagged. Do not refactor unrelated
+   code.
+
+### Suggestion comments → assess and decide
+
+For each suggestion:
+
+1. Evaluate whether the suggestion improves correctness, readability,
+   performance, or consistency with project conventions.
+2. **If beneficial** — apply the change (same rules as blocking comments).
+3. **If not applicable or would cause issues** — do NOT apply the change.
+   Instead, note the comment and your reasoning in the summary (Step 6).
+   Provide a brief, respectful explanation of why the suggestion was skipped
+   (e.g., "Skipped: this pattern is intentional for backward compatibility").
+
+### Informational comments → no action needed
+
+Acknowledge in the summary if relevant, but do not make code changes.
+
+### Common fix categories
+
+| Review finding | What to do |
+| --- | --- |
+| Missing `ConfigureAwait(false)` | Add it to every `await` in library code |
+| `init` accessor on new public API | Change to `set` or use constructor |
+| Missing `PublicAPI.Unshipped.txt` entry | Add the API signature |
+| Style / formatting violation | Fix to match `.editorconfig` |
+| Missing null check at boundary | Add guard clause |
+| Thread-safety issue | Apply appropriate synchronization |
+| Missing XML doc comment | Add concise doc comment |
+| Localization issue | Add/update `.resx` entry; do NOT edit `.xlf` files |
+
+## Step 4 — Verify the Build
+
+After applying all fixes:
+
+1. Run `dotnet build` on the affected project(s) or the solution if unsure which
+   projects are impacted.
+2. If there are **build errors**, fix them. Repeat until the build succeeds.
+3. Do **not** run the full test suite (it takes too long). Compilation
+   verification is sufficient.
+
+## Step 5 — Push Changes
+
+Use the `push_to_pull_request_branch` safe output tool to push all edited files to the
+PR branch. Provide a commit message in this format:
+
+```text
+Address review feedback
+
+Applied fixes for N review comments from the expert-reviewer.
+```
+
+Do **not** run `git add`, `git commit`, or `git push` directly — credentials are not
+available to the agent; the safe output handler manages authentication and enforces
+protected-file policies.
+
+## Step 6 — Post Summary
+
+Post a comment on the PR summarizing what was done. Use this format:
+
+> 🔧 **Autofix applied** — assessed N review comment(s).
+>
+> **Applied (M):**
+>
+> - `path/to/file.cs`: Brief description of change
+> - `path/to/other.cs`: Brief description of change
+>
+> **Skipped with explanation (K):**
+>
+> - *"Consider using Span\<T> here"* — Skipped: not applicable on netstandard2.0 TFM without polyfill.
+> - *"Nit: rename variable"* — Skipped: name is consistent with surrounding code.
+>
+> **No action needed (J):**
+>
+> - Informational / praise comments acknowledged.
+>
+> A re-review will be triggered automatically if code was pushed.
+> <!-- autofix-iteration -->
+
+Omit the **Skipped** or **No action needed** sections if they are empty.
+
+If **no code changes** were needed (all comments were informational or
+intentionally skipped), still post the summary but do **not** push a commit.
+
+The `<!-- autofix-iteration -->` marker is **required** for the circuit breaker.