🛡️ First try to CUE validation for description.yml files

.github/workflows/validate_descriptions.yml

@@ -0,0 +1,44 @@
+name: Validate Extension Descriptions
+
+on:
+  pull_request:
+    paths:
+      - 'extensions/*/description.yml'
+      - 'schema/description.cue'
+      - 'scripts/validate_descriptions.sh'
+      - '.github/workflows/validate_descriptions.yml'
+  push:
+    branches:
+      - main
+    paths:
+      - 'extensions/*/description.yml'
+      - 'schema/description.cue'
+      - 'scripts/validate_descriptions.sh'
+      - '.github/workflows/validate_descriptions.yml'
+  workflow_dispatch:
+
+jobs:
+  validate:
+    name: Validate description.yml files
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install CUE
+        uses: cue-lang/setup-cue@v1.0.1
+        with:
+          version: 'latest'
+
+      - name: Validate description.yml files
+        run: |
+          chmod +x scripts/validate_descriptions.sh
+          ./scripts/validate_descriptions.sh
+
+      - name: Summary
+        if: success()
+        run: |
+          echo "✅ All description.yml files validated successfully!" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "**Total files validated:** $(find extensions -name 'description.yml' | wc -l)" >> $GITHUB_STEP_SUMMARY

VALIDATION.md

@@ -0,0 +1,50 @@
+# Contributing Extension Validation Guide
+
+When adding or modifying a DuckDB community extension, your `description.yml` file must pass validation.
+
+## Quick Start
+
+Before submitting a PR:
+
+```bash
+# Install CUE (one-time setup)
+# macOS:
+brew install cue
+
+# Linux:
+curl -fsSL https://cuelang.org/install.sh | sh
+
+# Validate your changes
+./scripts/validate_descriptions.sh
+```
+
+## What Gets Validated?
+
+All `extensions/*/description.yml` files are checked for:
+- Required fields (name, description, language, build, maintainers)
+- Correct data types and formats
+- Valid GitHub repository references
+- Proper structure and syntax
+
+## Common Issues
+
+| Error | Solution |
+|-------|----------|
+| Missing required field | Add the field (e.g., `license: MIT`) |
+| Invalid GitHub format | Use `owner/repo` format in `repo.github` |
+| Wrong build system | Use `cmake`, `CMake`, or `cargo` |
+| Invalid version type | Quote string versions: `version: "1.0.0"` |
+
+## Full Documentation
+
+See [schema/README.md](schema/README.md) for:
+- Complete schema reference
+- Field-by-field documentation
+- Example files
+- Troubleshooting guide
+
+## CI Validation
+
+Your PR will automatically run validation. Fix any errors before the PR can be merged.
+
+**Need help?** Check the [validation documentation](schema/README.md) or ask in your PR.

extensions/capi_quack/description.yml

@@ -3,7 +3,7 @@ extension:
   description: Provides a hello world example demo from the C/C++ C API template
   version: 0.0.1
   language: C/C++
-  build: CMake
+  build: cmake
   license: MIT
   requires_toolchains: "python3"
   maintainers:

extensions/duckgl/description.yml

@@ -9,7 +9,7 @@ extension:
     - nkwork9999
 
 repo:
-  github: nkwork9999/duckgl # あなたのリポジトリ名に合わせて
+  github: nkwork9999/duckgl
   ref: 0de60a34e7bc04141fbc6b2efd6dcad6a80ac1e8
 
 docs:

schema/README.md

@@ -0,0 +1,185 @@
+# Extension Description Validation
+
+This repository uses [CUE](https://cuelang.org/) to validate all `description.yml` files for community extensions. This ensures consistency, catches errors early, and maintains high quality across all extension definitions.
+
+## What is Validated?
+
+The validation checks:
+- **Required fields**: name, description, language, build, maintainers, repo information
+- **Field types**: strings, numbers, lists are properly formatted
+- **GitHub repository format**: valid owner/repo structure
+- **Git references**: commit hashes or valid tags
+- **Build system**: valid build types (cmake, CMake, cargo)
+- **Consistent structure**: all extensions follow the same schema
+
+## Schema Definition
+
+The schema is defined in [`schema/description.cue`](../schema/description.cue) using CUE language. It specifies:
+
+### Required Top-Level Sections
+- `extension`: Extension metadata
+- `repo`: Repository information
+- `docs` (optional): Documentation
+
+### Extension Fields
+
+**Required:**
+- `name`: Extension name (non-empty string)
+- `description`: Brief description (non-empty string)
+- `language`: Programming language (e.g., "C++", "Rust")
+- `build`: Build system ("cmake", "CMake", or "cargo")
+- `maintainers`: List of maintainer GitHub usernames
+
+**Optional:**
+- `version`: Version string or number
+- `license`: License identifier (e.g., "MIT", "Apache-2.0")
+- `excluded_platforms`: Platforms to exclude (string or list)
+- `requires_toolchains`: Required toolchains (string or list)
+- `vcpkg_commit`: Specific vcpkg commit hash
+- And more (see schema file for complete list)
+
+### Repository Fields
+
+**Required:**
+- `github`: Repository in "owner/repo" format
+- `ref`: Git commit hash or tag
+
+**Optional:**
+- `ref_next`: Next reference for testing
+- `canonical_name`: Override canonical name
+
+### Documentation Fields
+
+**Optional:**
+- `hello_world`: Quick start example
+- `extended_description`: Detailed documentation
+- `docs_url`: External documentation URL
+
+## Validating Locally
+
+### Prerequisites
+
+Install CUE on your system:
+
+**macOS:**
+```bash
+brew install cue
+```
+
+**Linux:**
+```bash
+curl -fsSL https://cuelang.org/install.sh | sh
+```
+
+**From source:**
+```bash
+go install cuelang.org/go/cmd/cue@latest
+```
+
+### Run Validation
+
+From the repository root:
+
+```bash
+./scripts/validate_descriptions.sh
+```
+
+This will validate all 153 `description.yml` files and report any errors.
+
+### Validate a Single File
+
+```bash
+cue vet schema/description.cue extensions/YOUR_EXTENSION/description.yml -d "#Description"
+```
+
+## CI/CD Integration
+
+Validation runs automatically on:
+- **Pull Requests** that modify any `description.yml` file
+- **Pushes** to the main branch
+- **Manual trigger** via workflow_dispatch
+
+The workflow is defined in [`.github/workflows/validate_descriptions.yml`](../.github/workflows/validate_descriptions.yml).
+
+### Status Checks
+
+Pull requests must pass validation before merging. If validation fails:
+1. Review the error messages in the CI logs
+2. Fix the reported issues in your `description.yml`
+3. Push the changes to re-run validation
+
+## Common Validation Errors
+
+### Missing Required Field
+```
+extension.license: incomplete value string
+```
+**Fix:** Add the missing field to your `description.yml`
+
+### Invalid GitHub Format
+```
+repo.github: invalid value "invalid-format" (does not match ^[a-zA-Z0-9_-]+/[a-zA-Z0-9_.-]+$)
+```
+**Fix:** Use format "owner/repository-name"
+
+### Wrong Type
+```
+extension.version: conflicting values "1.0.0" and number
+```
+**Fix:** Version can be either string or number, but YAML interpretation matters. Quote strings: `version: "1.0.0"`
+
+### Invalid Build System
+```
+extension.build: conflicting values "cmake" and "make"
+```
+**Fix:** Use one of the allowed values: "cmake", "CMake", or "cargo"
+
+## Example Valid description.yml
+
+```yaml
+extension:
+  name: example
+  description: An example DuckDB extension
+  version: "1.0.0"
+  language: C++
+  build: cmake
+  license: MIT
+  maintainers:
+    - your-github-username
+
+repo:
+  github: your-org/your-extension
+  ref: abc123def456... # 40-character commit hash
+
+docs:
+  hello_world: |
+    SELECT example_function();
+  extended_description: |
+    Detailed documentation about your extension.
+    Can be multiple lines.
+```
+
+## Contributing
+
+When adding or modifying extensions:
+
+1. Ensure your `description.yml` follows the schema
+2. Run validation locally before pushing
+3. Address any validation errors before submitting PR
+4. CI will automatically validate your changes
+
+## Schema Updates
+
+If you need to add new fields to the schema:
+
+1. Update `schema/description.cue` with the new field definition
+2. Update this documentation
+3. Test against all existing extensions
+4. Submit PR with schema changes and documentation
+
+## Resources
+
+- [CUE Language Documentation](https://cuelang.org/docs/)
+- [CUE Tutorials](https://cuelang.org/docs/tutorials/)
+- [Schema Definition](../schema/description.cue)
+- [Validation Script](../scripts/validate_descriptions.sh)