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Merged
anakrish merged 1 commit into from
May 18, 2026
Merged

fix(copilot): robust diff computation for cloud agent environments #709

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2 changes: 2 additions & 0 deletions .github/copilot-setup-steps.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -8,3 +8,5 @@ steps:
- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
with:
fetch-depth: 0 # full history needed for git diff against main
- run: git fetch origin main:refs/remotes/origin/main
name: Ensure origin/main ref is available for diff computation
28 changes: 20 additions & 8 deletions .github/skills/code-review/SKILL.md
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Expand Up @@ -25,15 +25,21 @@ Key constraints (details in copilot-instructions.md):
## Step 1: Get the Diff

```bash
BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
|| git merge-base origin/main HEAD 2>/dev/null)
if [ -z "$BASE" ]; then
echo "ERROR: Cannot find upstream/main or origin/main. Cannot determine review scope."
exit 1
# Primary: use gh pr diff (works in cloud agent + any PR context).
# Fallback: git merge-base for local non-PR usage.
if gh pr diff --name-only >/dev/null 2>&1; then
echo "---STAT---"
gh pr diff --name-only
echo "---DIFF---"
gh pr diff
else
BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
|| git merge-base origin/main HEAD 2>/dev/null \
|| git merge-base main HEAD 2>/dev/null)
echo "Reviewing changes since: $BASE"
git diff "$BASE"..HEAD --stat
git diff "$BASE"..HEAD
fi
echo "Reviewing changes since: $BASE"
git diff "$BASE"..HEAD --stat
git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/'
```

If the diff is empty, stop and report: "No changes found to review."
Expand Down Expand Up @@ -196,3 +202,9 @@ one pass. If any were skipped, note them and briefly assess.
### Summary

X findings (N critical, N high, N medium, N low). One sentence overall assessment.

### Output

After generating the report above, write the COMPLETE report to `/tmp/code-review-report.md`
using the `create` tool or shell. This ensures the full report is preserved even if
display output is truncated.
59 changes: 38 additions & 21 deletions .github/skills/deep-review/SKILL.md
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Expand Up @@ -40,22 +40,25 @@ Use `read_agent` with `wait: true` to wait for each background agent.
## Step 1: Get the Diff and Build Inventory

```bash
BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
|| git merge-base origin/main HEAD 2>/dev/null)
if [ -z "$BASE" ]; then
echo "ERROR: Cannot find upstream/main or origin/main."
exit 1
# Primary: use gh pr diff (works in cloud agent + any PR context).
# Fallback: git merge-base for local non-PR usage.
if gh pr diff --name-only >/dev/null 2>&1; then
echo "---STAT---"
gh pr diff --name-only
echo "---DIFF---"
gh pr diff
else
BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
|| git merge-base origin/main HEAD 2>/dev/null \
|| git merge-base main HEAD 2>/dev/null)
echo "Reviewing changes since: $BASE"
git diff "$BASE"..HEAD --stat
git diff "$BASE"..HEAD
fi
echo "Reviewing changes since: $BASE"
git diff "$BASE"..HEAD --stat
git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/' | head -2000
```

If the diff is empty, stop and report: "No changes found to review."

**Scope rule:** Focus on code files (`*.rs`, `*.toml`, examples). Do NOT pass
docs/config diffs to agents.

**Build a risk-classified inventory.** List every changed function, struct,
impl, trait, pub item, and significant code block. Number them and tag with
risk predicates:
Expand Down Expand Up @@ -106,8 +109,10 @@ Use `model: "gpt-5.4"` in the task tool call (provides model diversity).
> Get the diff:
> ```
> BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
> || git merge-base origin/main HEAD 2>/dev/null)
> git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/'
> || git merge-base origin/main HEAD 2>/dev/null \
> || git merge-base main HEAD 2>/dev/null)
> # If no merge-base, use: gh pr diff
> git diff "$BASE"..HEAD # or: gh pr diff
> ```
>
> Key regorus constraints:
Expand Down Expand Up @@ -161,8 +166,10 @@ Use `model: "claude-opus-4.6"` in the task tool call.
> Get the diff AND read full source files for context:
> ```
> BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
> || git merge-base origin/main HEAD 2>/dev/null)
> git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/'
> || git merge-base origin/main HEAD 2>/dev/null \
> || git merge-base main HEAD 2>/dev/null)
> # If no merge-base, use: gh pr diff
> git diff "$BASE"..HEAD # or: gh pr diff
> ```
> Then use `view` to read the full source files that were changed.
>
Expand Down Expand Up @@ -219,8 +226,10 @@ Use the default model (no `model` parameter).
> Get the diff:
> ```
> BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
> || git merge-base origin/main HEAD 2>/dev/null)
> git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/'
> || git merge-base origin/main HEAD 2>/dev/null \
> || git merge-base main HEAD 2>/dev/null)
> # If no merge-base, use: gh pr diff
> git diff "$BASE"..HEAD # or: gh pr diff
> ```
> Use `view` to read surrounding context.
>
Expand Down Expand Up @@ -439,8 +448,10 @@ Launch **1 general-purpose agent in background mode**.
> Get the diff:
> ```
> BASE=$(git merge-base upstream/main HEAD 2>/dev/null \
> || git merge-base origin/main HEAD 2>/dev/null)
> git diff "$BASE"..HEAD -- '*.rs' '*.toml' 'examples/'
> || git merge-base origin/main HEAD 2>/dev/null \
> || git merge-base main HEAD 2>/dev/null)
> # If no merge-base, use: gh pr diff
> git diff "$BASE"..HEAD # or: gh pr diff
> ```
> Use `view` to read full source files.
>
Expand Down Expand Up @@ -481,8 +492,8 @@ Launch **1 general-purpose agent in background mode**.

## Step 5: Synthesize and Report

**IMPORTANT:** This is the primary output. Everything above was preparation.
Keep the report COMPACT — one finding per block, no filler prose.
**CRITICAL:** Write the report to `/tmp/deep-review-report.md` FIRST, then display it.
Use a shell command to write the file before any other output in this step.

Apply verdicts from the adversarial verifier:
- **CONFIRMED**: keep at stated severity
Expand Down Expand Up @@ -522,3 +533,9 @@ would catch it. If not, name the minimal test that should exist.
X findings (N critical, N high, N medium, N low). Y "likely" findings.
Z dropped (one-line reasons).
Risk assessment in one sentence.

---

**Remember:** The report above MUST be written to `/tmp/deep-review-report.md` at the
START of Step 5 (before displaying it). Use shell: `cat > /tmp/deep-review-report.md << 'REPORT_EOF'`
... report content ... `REPORT_EOF`
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