Add problem matcher for Yapf in CI

.github/problem-matchers/README.md

@@ -6,5 +6,11 @@ This directory contains Problem Matchers used by the GitHub Actions workflows in
 
 The following problem matcher JSON files found in this directory were copied from the [Home Assistant](https://github.com/home-assistant/core) project on GitHub. The Home Assistant project is licensed under the Apache 2.0 open-source license. The version of the files at the time they were copied was 2025.1.2.
 
-- [`pylint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/pylint.json)
-- [`yamllint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/yamllint.json)
+*   [`pylint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/pylint.json)
+*   [`yamllint.json`](https://github.com/home-assistant/core/blob/dev/.github/workflows/matchers/yamllint.json)
+
+The following problem matcher for yapf came from the [Google
+SCAAML](https://github.com/google/scaaml) repository as it appeared on 2025-12-08. The last commit
+was by user jmichelp on 2022-07-03. The file is licensed under the Apache 2.0 license.
+
+*   [`yapf.json`](https://github.com/google/scaaml/blob/6d9c3a42c527212ef77f2877419dd8f6e77eb442/.github/python_matcher.json)

.github/problem-matchers/yapf.json

@@ -0,0 +1,21 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "yapf-diff",
+      "pattern": [
+        {
+          "regexp": "^---\\s*([^\\s]*)\\s*\\(original\\)$",
+          "file": 1
+        },
+        {
+          "regexp": "^\\+\\+\\+\\s*([^\\s]*)\\s*\\((.*)\\)$",
+          "message": 2
+        },
+        {
+          "regexp": "^@@\\s*-(\\d+),(\\d+)\\s*\\+(\\d+),(\\d+)\\s*@@$",
+          "line": 1
+        }
+      ]
+    }
+  ]
+}

.github/workflows/ci-file-checks.yaml

@@ -333,6 +333,9 @@ jobs:
           path: ${{needs.Setup.outputs.cache_paths}}
           fail-on-cache-miss: true
 
+      - name: Set up yapf output problem matcher
+        run: echo '::add-matcher::.github/problem-matchers/yapf.json'
+
       - name: Run Yapf on the Python changed files
         run: |
           set +e