github-ci: fix link to whitespace error

When the `check-whitespace` CI job detects whitespace errors, a
formatted summary of the issue is generated. This summary contains links
to the commits and blobs responsible for the whitespace errors. The
generated links for blobs do not work and result in a 404.

Instead of using the reference name in the link, use the commit ID
directly. This fixes the broken link and also helps enable future
generalization of the script for other CI providers by removing one of
the GitHub specific CI variables used.

Signed-off-by: Justin Tobler <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: jltobler

.github/workflows/check-whitespace.yml

@@ -31,33 +31,34 @@ jobs:
         commit=
         commitText=
         commitTextmd=
-        goodparent=
+        goodParent=
         while read dash sha etc
         do
           case "${dash}" in
-          "---")
-            if test -z "${commit}"
+          "---") # Line contains commit information.
+            if test -z "${goodParent}"
             then
-              goodparent=${sha}
+              # Assume the commit has no whitespace errors until detected otherwise.
+              goodParent=${sha}
             fi
             commit="${sha}"
             commitText="${sha} ${etc}"
             commitTextmd="[${sha}](https://github.com/${{ github.repository }}/commit/${sha}) ${etc}"
             ;;
           "")
             ;;
-          *)
-            if test -n "${commit}"
+          *) # Line contains whitespace error information for current commit.
+            if test -n "${goodParent}"
             then
               problems+=("1) --- ${commitTextmd}")
               echo ""
               echo "--- ${commitText}"
-              commit=
+              goodParent=
             fi
             case "${dash}" in
             *:[1-9]*:) # contains file and line number information
               dashend=${dash#*:}
-              problems+=("[${dash}](https://github.com/${{ github.repository }}/blob/${{github.event.pull_request.head.ref}}/${dash%%:*}#L${dashend%:}) ${sha} ${etc}")
+              problems+=("[${dash}](https://github.com/${{ github.repository }}/blob/${commit}/${dash%%:*}#L${dashend%:}) ${sha} ${etc}")
               ;;
             *)
               problems+=("\`${dash} ${sha} ${etc}\`")
@@ -70,15 +71,15 @@ jobs:
 
         if test ${#problems[*]} -gt 0
         then
-          if test -z "${commit}"
+          if test -z "${goodParent}"
           then
-            goodparent=${baseSha: 0:7}
+            goodParent=${baseSha: 0:7}
           fi
           echo "🛑 Please review the Summary output for further information."
           echo "### :x: A whitespace issue was found in one or more of the commits." >$GITHUB_STEP_SUMMARY
           echo "" >>$GITHUB_STEP_SUMMARY
           echo "Run these commands to correct the problem:" >>$GITHUB_STEP_SUMMARY
-          echo "1. \`git rebase --whitespace=fix ${goodparent}\`" >>$GITHUB_STEP_SUMMARY
+          echo "1. \`git rebase --whitespace=fix ${goodParent}\`" >>$GITHUB_STEP_SUMMARY
           echo "1. \`git push --force\`" >>$GITHUB_STEP_SUMMARY
           echo " " >>$GITHUB_STEP_SUMMARY
           echo "Errors:" >>$GITHUB_STEP_SUMMARY