Github Issue Template

Skill: GitHub Issue Writing

Purpose

Write well-formatted GitHub issues for the Altinity ClickHouse repository following team conventions. Covers bug reports for regressions, upstream bugs, and flaky test tracking.

Repository

• Altinity repo: Altinity/ClickHouse — for Altinity-specific issues
• Upstream repo: ClickHouse/ClickHouse — for upstream bugs (only if no existing issue found)

Issue Template: Bug Report

Use this template for all bug reports. Adapt sections as needed based on the bug type.

✅ *I checked [the Altinity Stable Builds lifecycle table](https://docs.altinity.com/altinitystablebuilds/#altinity-stable-builds-life-cycle-table), and the Altinity Stable Build version I'm using is still supported.*

## Type of problem
**Bug report** - something's broken

## Describe the situation
<1-3 paragraphs explaining:>
<- What the bug is>
<- When/how it was discovered (CI job, manual testing, customer report)>
<- Impact: crash, wrong results, error message, etc.>

This issue:
- <key fact 1, e.g., "Causes SIGABRT on debug/sanitizer builds">
- <key fact 2, e.g., "Returns error code 1001 on release builds">
- <key fact 3, e.g., "Is a pre-existing upstream bug dating back to July 2024">

---

## How to reproduce the behavior

### Environment
- **Version:** <exact version string>
- **Build type:** <release / debug / sanitizer>

### Steps

1. <step 1>

```sql
<SQL or commands for step 1>

2. <step 2>

<SQL or commands for step 2>

3. <step 3>

<SQL or commands for step 3>

Expected behavior

Actual behavior

On release builds

<exact error output>

On debug/sanitizer builds (if applicable)

<SIGABRT / crash details>

<stack trace, trimmed to relevant frames>

Root cause analysis

Additional context

CI failure

• Job:
• Branch:
• Commit: <sha>
• CI report: ci_run_report.html
• Logs: json.html

<Related PRs, upstream history, workarounds, etc.>

---

## Section Guidelines

### Describe the situation
- Lead with what's broken, not how you found it
- State the severity: crash vs error vs wrong results
- If it's an upstream bug, say so explicitly and mention since when

### How to reproduce
- Minimal steps — remove anything not needed to trigger the bug
- Include exact SQL queries and settings
- For fuzzer-found bugs: extract the crashing query from `fatal.log` and the required settings from the `Changed settings:` line

### Expected vs Actual behavior
- Be specific: "should return 3 rows" not "should work"
- For crashes: show both release behavior (error message) and debug behavior (SIGABRT + stack trace)

### Root cause analysis
- Optional but highly valued by the team
- Reference specific source files and functions if known
- If from stack trace analysis, include the key frames

### Additional context
- Always include CI links
- For upstream bugs: include the upstream CI history (query results from `play.clickhouse.com`)
- For regressions: reference the PR that introduced the change
- For flaky tests: include fail rate and time range

---

## Bug Type Variations

### Upstream Bug (not Altinity-specific)

Add to "Describe the situation":
```markdown
- Is a **pre-existing upstream bug** — present in the upstream ClickHouse CI since **<date>** with <N>+ occurrences
- Was detected in **Altinity Stable Build <version>** via the <job name> CI job
- No existing GitHub issue was found upstream tracking this failure

Add "Upstream CI history" subsection under Additional context:

### Upstream CI history

| Month | Upstream CI hits |
|-------|-----------------|
| <month> | <count> |
| ... | ... |

Regression from Specific PR

Add to Additional context:

### Related PR
- PR #<NUMBER>: <title> — introduced the change that caused this regression

Flaky Test

Add to Additional context:

### Flakiness data
- **Fail rate:** <X>% over the last 30 days
- **Affected build types:** <list>
- **First seen:** <date>
- **Pattern:** <consistent error vs varying>

Creating the Issue

gh issue create --repo Altinity/ClickHouse \
  --title "<concise title>" \
  --label "bug" \
  --body "$(cat <<'EOF'
<issue body here>
EOF
)"

Common labels: bug, stable, antalya, antalya-25.8, 25.8, 25.8.16

Reference Issues

Good examples of well-formatted issues in the Altinity repo:

• #1412 — Regression with full reproduction, root cause, and workaround
• #1437 — Bug with suggested fix in the issue body

Related Skills

• pr-ci-failure-triage — Identifies which failures need issues filed
• upstream-test-investigation — Gathers the data needed for the issue body
• upstream-ci-database-queries — Provides upstream CI history for cross-referencing