Split clang-format check into a separate script

Author: thomasspriggs

.github/workflows/pull-request-check-clang-format.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+# Stop on errors
+set -e
+
+# Log information about the run of this check.
+echo "Pull request's base branch is: ${BASE_BRANCH}"
+echo "Pull request's merge branch is: ${MERGE_BRANCH}"
+echo "Pull request's source branch is: ${GITHUB_HEAD_REF}"
+clang-format-7 --version
+
+# The checkout action leaves us in detatched head state. The following line
+# names the checked out commit, for simpler reference later.
+git checkout -b ${MERGE_BRANCH}
+
+# Build list of files to ignore 
+while read file ; do EXCLUDES+="':(top,exclude)$file' " ; done < .clang-format-ignore
+
+# Make sure we can refer to ${BASE_BRANCH} by name
+git checkout ${BASE_BRANCH}
+git checkout ${MERGE_BRANCH}
+
+# Find the commit on which the PR is based.
+MERGE_BASE=$(git merge-base ${BASE_BRANCH} ${MERGE_BRANCH})
+echo "Checking for formatting errors introduced since $MERGE_BASE"
+
+# Do the checking. "eval" is used so that quotes (as inserted into $EXCLUDES
+# above) are not interpreted as parts of file names.
+eval git-clang-format-7 --binary clang-format-7 $MERGE_BASE -- $EXCLUDES
+git diff > formatted.diff
+if [[ -s formatted.diff ]] ; then
+  echo 'Formatting error! The following diff shows the required changes'
+  echo 'Use the raw log to get a version of the diff that preserves spacing'
+  cat formatted.diff
+  exit 1
+fi
+echo 'No formatting errors found'
+exit 0

.github/workflows/pull-request-checks.yaml

@@ -143,25 +143,4 @@ jobs:
         env:
           BASE_BRANCH: ${{ github.base_ref }}
           MERGE_BRANCH: ${{ github.ref }}
-        run: |
-          echo "Pull request's base branch is: ${BASE_BRANCH}"
-          echo "Pull request's merge branch is: ${MERGE_BRANCH}"
-          echo "Pull request's source branch is: ${GITHUB_HEAD_REF}"
-          clang-format-7 --version
-          git checkout -b ${MERGE_BRANCH}
-          while read file ; do EXCLUDES+="':(top,exclude)$file' " ; done < .clang-format-ignore
-          git checkout ${BASE_BRANCH}
-          git checkout ${MERGE_BRANCH}
-          MERGE_BASE=$(git merge-base ${BASE_BRANCH} ${MERGE_BRANCH})
-          echo "Checking for formatting errors introduced since $MERGE_BASE"
-          # use eval so that quotes (as inserted into $EXCLUDES above) are not interpreted as parts of file names
-          eval git-clang-format-7 --binary clang-format-7 $MERGE_BASE -- $EXCLUDES
-          git diff > formatted.diff
-          if [[ -s formatted.diff ]] ; then
-            echo 'Formatting error! The following diff shows the required changes'
-            echo 'Use the raw log to get a version of the diff that preserves spacing'
-            cat formatted.diff
-            exit 1
-          fi
-          echo 'No formatting errors found'
-          exit 0
+        run: ./.github/workflows/pull-request-check-clang-format.sh