[CI] Add nicer OpenAPI diffs (#7002)

* add diff action

* Update api_version.py

* always diff schemas

* move model lookup to subpath

* Add diff to step summary

* fix arg name

* use echo step instead

* split action and fail curl

* fail if download not possible

* capture code

* remove wrong syntax

* decrease download number

* revert qc

* extend version_check

* fix exit cond

* fix link

* add dummy change

* Update api_version.py

* use html for format

.github/workflows/qc_checks.yaml

@@ -164,15 +164,27 @@ jobs:
           name: schema.yml
           path: src/backend/InvenTree/schema.yml
       - name: Download public schema
-        if: needs.paths-filter.outputs.api == 'false'
         run: |
           pip install --require-hashes -r contrib/dev_reqs/requirements.txt >/dev/null 2>&1
-          version="$(python3 .github/scripts/version_check.py only_version 2>&1)"
+          version="$(python3 .github/scripts/version_check.py only_version ${{ needs.paths-filter.outputs.api }} 2>&1)"
           echo "Version: $version"
           url="https://raw.githubusercontent.com/inventree/schema/main/export/${version}/api.yaml"
           echo "URL: $url"
-          curl -s -o api.yaml $url
+          code=$(curl -s -o api.yaml $url --write-out '%{http_code}' --silent)
+          if [ "$code" != "200" ]; then
+            exit 1
+          fi
           echo "Downloaded api.yaml"
+      - name: Running OpenAPI Spec diff action
+        id: breaking_changes
+        uses: oasdiff/oasdiff-action/diff@main
+        with:
+          base: 'api.yaml'
+          revision: 'src/backend/InvenTree/schema.yml'
+          format: 'html'
+      - name: Echoing diff to step
+        run: echo "${{ steps.breaking_changes.outputs.diff }}" >> $GITHUB_STEP_SUMMARY
+
       - name: Check for differences in API Schema
         if: needs.paths-filter.outputs.api == 'false'
         run: |