ci: tighten release pipeline + enforce conventional-commit format

.pre-commit-config.yaml

@@ -83,6 +83,15 @@ repos:
     hooks:
       - id: typos
 
+  # Conventional-commit message validation. Runs at commit-msg stage so the
+  # message format (`type(scope)!: subject` + optional body + Refs) is
+  # checked before the commit lands. Spec lives in docs/COMMIT_MESSAGE_STANDARD.md.
+  - repo: https://github.com/commitizen-tools/commitizen
+    rev: 4fbeae7861663ecf4b4989211eba41c1a3fb1227  # v4.13.9
+    hooks:
+      - id: commitizen
+        stages: [commit-msg]
+
   # Generated README must match tests/test_readme_examples.py.
   # Drift blocks commit — regenerate with `python scripts/generate_readme.py`.
   # The script uses only stdlib (ast, re, textwrap), so `language: python`

.release-please-manifest.json

@@ -1,4 +1,3 @@
 {
-  ".": "3.0.0",
-  "mat-rs": "0.2.0"
+  ".": "3.0.0"
 }

docs/COMMIT_MESSAGE_STANDARD.md

@@ -48,6 +48,24 @@ Only the following types are allowed:
 
 Any other type (e.g. `feature`, `bugfix`, or emoji-based prefixes) is **not** allowed.
 
+## Approved scopes
+
+The `(scope)` is **optional** but recommended in this multi-package monorepo. A correctly-attributed scope makes Release PR review faster, prevents cross-cutting commits from triggering false bumps in unrelated packages (see [#50](https://github.com/MorePET/mat/issues/50), [#55](https://github.com/MorePET/mat/issues/55)), and makes the CHANGELOG self-documenting.
+
+| Scope | Meaning | Example |
+|-------|---------|---------|
+| `(py)` | py-materials Python package code | `feat(py): add Material.melting_point_qty` |
+| `(rs)` | rs-materials Rust crate code | `feat(rs)!: rename MaterialDb to Catalog` |
+| `(data)` | TOML data files (shared between py + rs via symlinks) | `fix(data): correct stainless density to 8.0 g/cm³` |
+| `(vis)` | The vis subsystem (Python-side, mat-vis-client integration) | `feat(vis): expose .mtlx() façade` |
+| `(deps)` | Dependency bumps (typically from dependabot) | `build(deps): bump mat-vis-client to 0.5.0` |
+| `(ci)` | CI workflows, release pipeline, automation | `ci: gate crates.io publish on repo var` |
+| `(docs)` | Documentation only | `docs(migration): add v3-to-v4 stub` |
+
+**No scope** is acceptable for cross-cutting work that genuinely touches multiple packages — but **prefer splitting into per-scope commits** when possible. Squash-merging a multi-scope PR collapses these distinctions and can mislead release tooling (the rationale documented in [issue #50](https://github.com/MorePET/mat/issues/50)).
+
+Scopes are validated for *format* (alphanumeric + hyphens) by the commit-msg hook (commitizen), not for *membership* in the table above — the table is a strong convention enforced socially via review.
+
 ## Refs line and traceability
 
 The `Refs:` line provides mandatory traceability to issues, requirements, risks, or SOPs. Only one `Refs:` line is allowed; it must be the last non-empty line of the message.

pyproject.toml

@@ -76,6 +76,17 @@ target-version = "py311"
 [tool.ruff.lint]
 select = ["E", "F", "W", "I"]
 
+# Commitizen — conventional-commit message validation at commit-msg stage
+# (configured via .pre-commit-config.yaml). Using the default
+# `cz_conventional_commits` rule set; the project's allowed types and the
+# scope taxonomy are documented in docs/COMMIT_MESSAGE_STANDARD.md and
+# enforced socially via review (commitizen permits any scope by default).
+[tool.commitizen]
+name = "cz_conventional_commits"
+version = "3.0.0"
+tag_format = "v$version"
+update_changelog_on_bump = false
+
 [dependency-groups]
 dev = [
     "ruff>=0.15.10",

release-please-config.json

@@ -26,13 +26,6 @@
           "path": "src/pymat/__init__.py"
         }
       ]
-    },
-    "mat-rs": {
-      "release-type": "rust",
-      "package-name": "rs-materials",
-      "component": "rs-materials",
-      "include-component-in-tag": true,
-      "tag-separator": "/"
     }
   }
 }