feat: add automated crash reporting for array_ops fuzzing

Add Claude-powered crash analysis and GitHub issue creation for the array_ops
fuzzing target, matching the existing file_io fuzzing setup.

Changes:
- Add crash detection and reporting to ops_fuzz job
- Add report-ops-fuzz-failures job with Claude analysis
- Use environment variables to parameterize shared Claude prompt logic

This enables automated issue creation for array_ops fuzzing crashes,
matching the existing file_io crash reporting functionality.

Signed-off-by: Joe Isaacs <[email protected]>

Author: joseph-isaacs

.github/workflows/fuzz.yml

@@ -129,6 +129,8 @@ jobs:
           ARTIFACT_URL: ${{ needs.io_fuzz.outputs.artifact_url }}
           BRANCH: ${{ github.ref_name }}
           COMMIT: ${{ github.sha }}
+          FUZZ_TARGET: file_io
+          ARTIFACT_NAME: io-fuzzing-crash-artifacts
         uses: anthropics/claude-code-action@v1
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
@@ -137,7 +139,7 @@ jobs:
           prompt: |
             # Fuzzer Crash Analysis and Reporting
 
-            A fuzzing run for the `file_io` target has detected a crash. Analyze it and report by creating or updating a GitHub issue.
+            A fuzzing run for the `$FUZZ_TARGET` target has detected a crash. Analyze it and report by creating or updating a GitHub issue.
 
             ## Step 1: Analyze the Crash
 
@@ -248,7 +250,7 @@ jobs:
 
             ### Summary
 
-            - **Target**: `file_io`
+            - **Target**: `$FUZZ_TARGET`
             - **Crash File**: `$CRASH_FILE`
             - **Branch**: $BRANCH
             - **Commit**: $COMMIT
@@ -258,18 +260,18 @@ jobs:
 
             1. Download the crash artifact:
                - **Direct download**: $ARTIFACT_URL
-               - Or find `io-fuzzing-crash-artifacts` at: $WORKFLOW_RUN
+               - Or find `$ARTIFACT_NAME` at: $WORKFLOW_RUN
                - Extract the zip file
 
             2. Reproduce locally:
             ```bash
-            # The artifact contains file_io/$CRASH_FILE
-            cargo +nightly fuzz run --sanitizer=none file_io file_io/$CRASH_FILE
+            # The artifact contains $FUZZ_TARGET/$CRASH_FILE
+            cargo +nightly fuzz run --sanitizer=none $FUZZ_TARGET $FUZZ_TARGET/$CRASH_FILE
             ```
 
             3. Get full backtrace:
             ```bash
-            RUST_BACKTRACE=full cargo +nightly fuzz run --sanitizer=none file_io file_io/$CRASH_FILE
+            RUST_BACKTRACE=full cargo +nightly fuzz run --sanitizer=none $FUZZ_TARGET $FUZZ_TARGET/$CRASH_FILE
             ```
 
             ---
@@ -289,6 +291,8 @@ jobs:
             - ARTIFACT_URL: $ARTIFACT_URL (direct link to crash artifact)
             - BRANCH: $BRANCH
             - COMMIT: $COMMIT
+            - FUZZ_TARGET: $FUZZ_TARGET
+            - ARTIFACT_NAME: $ARTIFACT_NAME
 
             Start by reading `logs/fuzz_output.log`.
           claude_args: |
@@ -307,6 +311,10 @@ jobs:
       - disk=large
       - extras=s3-cache
       - tag=ops-fuzz
+    outputs:
+      crashes_found: ${{ steps.check.outputs.crashes_found }}
+      first_crash_name: ${{ steps.check.outputs.first_crash_name }}
+      artifact_url: ${{ steps.upload_artifacts.outputs.artifact-url }}
     steps:
       - uses: runs-on/action@v2
         with:
@@ -335,13 +343,47 @@ jobs:
           AWS_ENDPOINT_URL: "https://01e9655179bbec953276890b183039bc.r2.cloudflarestorage.com"
       - name: Run fuzzing target
         id: fuzz
-        run: RUST_BACKTRACE=1 cargo +nightly fuzz run --release --debug-assertions array_ops -- -max_total_time=7200
+        run: |
+          RUST_BACKTRACE=1 cargo +nightly fuzz run --release --debug-assertions array_ops -- -max_total_time=7200 2>&1 | tee fuzz_output.log
         continue-on-error: true
+      - name: Check for crashes
+        id: check
+        run: |
+          if [ -d "fuzz/artifacts" ] && [ "$(ls -A fuzz/artifacts 2>/dev/null)" ]; then
+            echo "crashes_found=true" >> $GITHUB_OUTPUT
+
+            # Get the first crash file only
+            FIRST_CRASH=$(find fuzz/artifacts -type f \( -name "crash-*" -o -name "leak-*" -o -name "timeout-*" -o -name "oom-*" \) | head -1)
+
+            if [ -n "$FIRST_CRASH" ]; then
+              echo "first_crash=$FIRST_CRASH" >> $GITHUB_OUTPUT
+              echo "first_crash_name=$(basename $FIRST_CRASH)" >> $GITHUB_OUTPUT
+
+              # Count all crashes for reporting
+              CRASH_COUNT=$(find fuzz/artifacts -type f \( -name "crash-*" -o -name "leak-*" -o -name "timeout-*" -o -name "oom-*" \) | wc -l)
+              echo "crash_count=$CRASH_COUNT" >> $GITHUB_OUTPUT
+              echo "Found $CRASH_COUNT crash(es), will process first: $(basename $FIRST_CRASH)"
+            fi
+          else
+            echo "crashes_found=false" >> $GITHUB_OUTPUT
+            echo "crash_count=0" >> $GITHUB_OUTPUT
+            echo "No crashes found"
+          fi
       - name: Archive crash artifacts
+        id: upload_artifacts
+        if: steps.check.outputs.crashes_found == 'true'
         uses: actions/upload-artifact@v5
         with:
           name: operations-fuzzing-crash-artifacts
           path: fuzz/artifacts
+          retention-days: 30
+      - name: Archive fuzzer output log
+        if: steps.check.outputs.crashes_found == 'true'
+        uses: actions/upload-artifact@v4
+        with:
+          name: ops-fuzzing-logs
+          path: fuzz_output.log
+          retention-days: 30
       - name: Persist corpus
         shell: bash
         run: |
@@ -353,5 +395,202 @@ jobs:
           AWS_REGION: "us-east-1"
           AWS_ENDPOINT_URL: "https://01e9655179bbec953276890b183039bc.r2.cloudflarestorage.com"
       - name: Fail job if fuzz run found a bug
-        if: steps.fuzz.outcome == 'failure'
+        if: steps.check.outputs.crashes_found == 'true'
         run: exit 1
+
+  report-ops-fuzz-failures:
+    name: "Report Array Operations Fuzz Failures"
+    needs: ops_fuzz
+    if: always() && needs.ops_fuzz.outputs.crashes_found == 'true'
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      contents: read
+      id-token: write
+      pull-requests: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v5
+
+      - name: Download fuzzer logs
+        uses: actions/download-artifact@v4
+        with:
+          name: ops-fuzzing-logs
+          path: ./logs
+
+      - name: Analyze and report crash with Claude
+        env:
+          CRASH_FILE: ${{ needs.ops_fuzz.outputs.first_crash_name }}
+          ARTIFACT_URL: ${{ needs.ops_fuzz.outputs.artifact_url }}
+          BRANCH: ${{ github.ref_name }}
+          COMMIT: ${{ github.sha }}
+          FUZZ_TARGET: array_ops
+          ARTIFACT_NAME: operations-fuzzing-crash-artifacts
+        uses: anthropics/claude-code-action@v1
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          show_full_output: true
+          prompt: |
+            # Fuzzer Crash Analysis and Reporting
+
+            A fuzzing run for the `$FUZZ_TARGET` target has detected a crash. Analyze it and report by creating or updating a GitHub issue.
+
+            ## Step 1: Analyze the Crash
+
+            1. Read the fuzzer log: `logs/fuzz_output.log`
+            2. Extract:
+               - Stack trace (lines with `#0`, `#1`, etc.)
+               - Error message ("panicked at" or "ERROR:")
+               - Crash location (top user code frame, not std/core/libfuzzer)
+               - Debug output (look for "Output of `std::fmt::Debug`:" section before the crash)
+            3. Read the source code at the crash location to understand root cause
+
+            ## Step 2: Check for Duplicates
+
+            1. List existing fuzzer issues:
+               ```bash
+               gh issue list --repo ${{ github.repository }} --label fuzzer --state open --json number,title,body --limit 50
+               ```
+
+            2. For each existing issue, compare:
+               - **Crash location**: Same file + function? (line numbers can differ)
+               - **Error pattern**: Same error after normalizing values?
+                 - "index 5 out of bounds" = "index 12 out of bounds" (SAME)
+                 - "len is 100" = "len is 5" (SAME)
+               - Read source code if needed to verify same root cause
+
+            3. Determine duplication level:
+               - **EXACT DUPLICATE**: Same crash location + same error pattern → Add reaction
+               - **SIMILAR**: Same general area but unclear → Add comment
+               - **NEW BUG**: Different location or different error type → Create new issue
+
+            ## Step 3: Take Action
+
+            ### If EXACT DUPLICATE (high confidence):
+            Update or create a tracking comment to count occurrences:
+
+            1. First, check if there's already a tracking comment (look for a comment starting with "<!-- occurrences: ")
+            2. If found, extract the count, increment it, and edit the comment
+            3. If not found, create a new comment
+
+            Comment format:
+            ```markdown
+            <!-- occurrences: N -->
+            **Crash seen N time(s)**
+
+            Latest occurrence:
+            - Crash file: $CRASH_FILE
+            - Artifact: $ARTIFACT_URL
+            - Branch: $BRANCH
+            - Commit: $COMMIT
+            ```
+
+            Use:
+            - `gh api repos/${{ github.repository }}/issues/ISSUE_NUM/comments` to list comments
+            - `gh api repos/${{ github.repository }}/issues/comments/COMMENT_ID -X PATCH` to update
+            - `gh issue comment ISSUE_NUM` to create new
+
+            ### If SIMILAR (medium confidence):
+            Comment on the existing issue with analysis:
+            ```bash
+            gh issue comment ISSUE_NUM --repo ${{ github.repository }} --body "..."
+            ```
+
+            Include in comment:
+            - Note that another crash was detected
+            - Your confidence level and reasoning
+            - Key differences if any
+            - Crash file: $CRASH_FILE
+            - Workflow: $WORKFLOW_RUN
+
+            ### If NEW BUG (not a duplicate):
+            Create a new issue with `gh issue create`:
+            ```bash
+            gh issue create --repo ${{ github.repository }} \
+              --title "Fuzzing Crash: [brief description]" \
+              --label "bug,fuzzer" \
+              --body "..."
+            ```
+
+            Issue body must include:
+            ```markdown
+            ## Fuzzing Crash Report
+
+            ### Analysis
+
+            **Crash Location**: `file.rs:function_name`
+
+            **Error Message**:
+            ```
+            [error message]
+            ```
+
+            **Stack Trace**:
+            ```
+            [top 5-7 frames - keep in code block to prevent markdown rendering issues]
+            ```
+
+            Note: Keep stack traces in code blocks to prevent `#0`, `#1` from being interpreted as markdown headers.
+
+            **Root Cause**: [Your analysis]
+
+            <details>
+            <summary>Debug Output</summary>
+
+            ```
+            [Include the complete "Output of std::fmt::Debug:" section from the fuzzer log]
+            ```
+            </details>
+
+            ### Summary
+
+            - **Target**: `$FUZZ_TARGET`
+            - **Crash File**: `$CRASH_FILE`
+            - **Branch**: $BRANCH
+            - **Commit**: $COMMIT
+            - **Crash Artifact**: $ARTIFACT_URL
+
+            ### Reproduction
+
+            1. Download the crash artifact:
+               - **Direct download**: $ARTIFACT_URL
+               - Or find `$ARTIFACT_NAME` at: $WORKFLOW_RUN
+               - Extract the zip file
+
+            2. Reproduce locally:
+            ```bash
+            # The artifact contains $FUZZ_TARGET/$CRASH_FILE
+            cargo +nightly fuzz run --sanitizer=none $FUZZ_TARGET $FUZZ_TARGET/$CRASH_FILE
+            ```
+
+            3. Get full backtrace:
+            ```bash
+            RUST_BACKTRACE=full cargo +nightly fuzz run --sanitizer=none $FUZZ_TARGET $FUZZ_TARGET/$CRASH_FILE
+            ```
+
+            ---
+            *Auto-created by fuzzing workflow with Claude analysis*
+            ```
+
+            ## Important Guidelines
+
+            - Be conservative: when unsure, prefer creating a new issue over marking as duplicate
+            - Focus on ROOT CAUSE, not specific values in error messages
+            - You have full repo access - read source code to understand crashes
+            - Only use +1 reaction for truly identical crashes
+
+            ## Environment Variables
+
+            - CRASH_FILE: $CRASH_FILE
+            - ARTIFACT_URL: $ARTIFACT_URL (direct link to crash artifact)
+            - BRANCH: $BRANCH
+            - COMMIT: $COMMIT
+            - FUZZ_TARGET: $FUZZ_TARGET
+            - ARTIFACT_NAME: $ARTIFACT_NAME
+
+            Start by reading `logs/fuzz_output.log`.
+          claude_args: |
+            --model claude-sonnet-4-5-20250929
+            --max-turns 25
+            --allowedTools "Read,Write,Bash(gh issue list:*),Bash(gh issue view:*),Bash(gh issue create:*),Bash(gh issue comment:*),Bash(gh api:*),Bash(echo:*),Bash(cat:*),Bash(jq:*),Bash(grep:*),Bash(cargo +nightly fuzz run:*),Bash(RUST_BACKTRACE=* cargo +nightly fuzz run:*)"