Add PRdoc check (#1408)

* Add test prdoc
* Prepare for the check
* Escape PR number
* Fix conditional step
* Add checkout and actual check
* Cleanup
* Minor fixes
* Add doumentation
* Add more doc

.github/workflows/check-prdoc.yml

+name: Check PRdoc
+
+on:
+  pull_request:
+    types: [labeled, opened, synchronize, unlabeled]
+
+env:
+  # todo: switch to paritytech/prdoc once the container is built & published
+  # see https://github.com/paritytech/scripts/pull/595
+  IMAGE: chevdor/prdoc:v0.0.4
+  API_BASE: https://api.github.com/repos
+  REPO: ${{ github.repository }}
+  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+  GITHUB_PR: ${{ github.event.pull_request.number }}
+  MOUNT: /prdoc
+  ENGINE: docker
+
+jobs:
+  check-prdoc:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Pull image
+        run: |
+          echo "Pulling $IMAGE"
+          docker pull $IMAGE
+          docker run --rm $IMAGE --version
+
+      - name: Check if PRdoc is required
+        id: get-labels
+        run: |
+            # Fetch the labels for the PR under test
+            echo "Fetch the labels for $API_BASE/${REPO}/pulls/${GITHUB_PR}"
+            labels=$( curl -H "Authorization: token ${GITHUB_TOKEN}" -s "$API_BASE/${REPO}/pulls/${GITHUB_PR}" | jq '.labels | .[] | .name' | tr "\n" ",")
+            echo "Labels: ${labels}"
+            echo "labels=${labels}" >> "$GITHUB_OUTPUT"
+
+      - name: No PRdoc required
+        if: ${{ contains(steps.get-labels.outputs.labels, 'R0') }}
+        run: |
+          echo "PR detected as silent, no PRdoc is required, exiting..."
+          exit 0
+
+      - name: Checkout repo
+        if: ${{ !contains(steps.get-labels.outputs.labels, 'R0') }}
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac #v4.0.0
+
+      - name: PRdoc check for PR#${{ github.event.pull_request.number }}
+        if: ${{ !contains(steps.get-labels.outputs.labels, 'R0') }}
+        run: |
+          echo "Checking for PR#$GITHUB_PR in $MOUNT"
+          $ENGINE run --rm -v $PWD/prdoc:/doc $IMAGE check -n 1408

cumulus/scripts/ci/changelog/README.md

@@ -61,7 +61,7 @@ all the labels that are used, search for `meta` in the templates. Currently, the
 Note that labels with the same letter are mutually exclusive. A PR should not have both `B0` and `B5`, or both `C1` and
 `C9`. In case of conflicts, the template will decide which label will be considered.
 
-## Dev and debuggin
+## Dev and debugging
 
 ### Hot Reload
 

docs/CONTRIBUTING.md

@@ -80,18 +80,36 @@ Reviews should finish with approval unless there are issues that would result in
 
 The reviewers are also responsible to check:
 
-a) if a changelog is necessary and attached
-
-b) the quality of information in the changelog file
-
-c) the PR has an impact on docs
-
-d) that the docs team was included in the review process of a docs update
+1. if a changelog is necessary and attached
+1. the quality of information in the changelog file
+1. the PR has an impact on docs
+1. that the docs team was included in the review process of a docs update
 
 **Reviews may not be used as an effective veto for a PR because**:
 1. There exists a somewhat cleaner/better/faster way of accomplishing the same feature/fix.
 2. It does not fit well with some other contributors' longer-term vision for the project.
 
+## Documentation
+
+All Pull Requests must contain proper title & description.
+
+Some Pull Requests can be exempt of `prdoc` documentation, those
+must be labelled with
+[`R0-silent`](https://github.com/paritytech/labels/blob/main/ruled_labels/specs_polkadot-sdk.yaml#L89-L91).
+
+Non "silent" PRs must come with documentation in the form of a `.prdoc` file.
+A `.prdoc` documentation is made of a text file (YAML) named `/prdoc/pr_NNNN.prdoc` where `NNNN` is the PR number.
+For convenience, those file can also contain a short description/title: `/prdoc/pr_NNNN_pr-foobar.prdoc`.
+
+The CI automation checks for the presence and validity of a `prdoc` in the `/prdoc` folder.
+Those files need to comply with a specific [schema](https://github.com/paritytech/prdoc/blob/master/schema_user.json). It
+is highly recommended to [make your editor aware](https://github.com/paritytech/prdoc#schemas) of the schema as it is
+self-described and will assist you in writing correct content.
+
+This schema is also embedded in the
+[prdoc](https://github.com/paritytech/prdoc) utility that can also be used to generate and check the validity of a
+`prdoc` locally.
+
 ## Helping out
 
 We use [labels](https://github.com/paritytech/polkadot-sdk/labels) to manage PRs and issues and communicate

prdoc/pr_1408_prodc-introduction.prdoc

+# This PR does not need a prdoc but it is provided in order to test
+title: PRdoc check
+
+doc:
+  - audience: Core Dev
+    description: |
+      This PRdoc is an **example**.
+
+      This PR brings support and automated checks for documentation in the form of a
+      [`prdoc`](https://github.com/paritytech/prdoc/) file.
+
+migrations:
+  db: []
+
+  runtime: []
+
+crates: []
+
+host_functions: []