fix(developer): handle merge commits when checking git log date

developer/src/kmc/src/util/getLastGitCommitDate.ts

@@ -9,22 +9,54 @@ export const expectedGitDateFormat = /^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d(\.\d\d\
  * @returns string, in RFC3339, 'YYYY-MM-DDThh:nn:ss.SSSZ'
  */
 export function getLastGitCommitDate(path: string): string {
-  // TZ=UTC0 git log -1 --no-merges --date=format:%Y-%m-%dT%H:%M:%SZ --format=%ad
-  let result = null;
+  // git log -1 --no-merges --format=%at
+  let result = callGitLog([
+    'log',                                // git log
+    '-1',                                 // one commit only
+    '--no-merges',                        // we're only interested in 'real' commits
+    '--format=%at',                       // emit only the commit date as a UNIX timestamp
+    '--',
+    path
+  ]);
 
-  try {
-    result = execFileSync('git', [
+  if(typeof result != 'string') {
+    return null;
+  }
+
+  if(result == '') {
+    // #12626: no history was found, but not an error. We may have only a merge
+    // commit in history for that file, allow merges in the log
+    result = callGitLog([
       'log',                                // git log
       '-1',                                 // one commit only
-      '--no-merges',                        // we're only interested in 'real' commits
       '--format=%at',                       // emit only the commit date as a UNIX timestamp
       '--',
       path
-    ], {
+    ]);
+
+    if(typeof result != 'string') {
+      return null;
+    }
+  }
+
+  const sec = Number.parseInt(result);
+  if(Number.isNaN(sec)) {
+    // We received invalid data, perhaps a git error string so just ignore
+    return null;
+  }
+
+  // We receive a timestamp in seconds but we need milliseconds
+  return new Date(sec * 1000).toISOString();
+}
+
+function callGitLog(params: string[]) {
+  try {
+    const result = execFileSync('git', params, {
       encoding: 'utf-8',                    // force a string result rather than Buffer
       windowsHide: true,                    // on windows, we may need this to suppress a console window popup
       stdio: ['pipe', 'pipe', 'pipe']       // all output via pipe, so we don't get git errors on console
     });
+    return result.trim();
   } catch (e) {
     // If git is not available, or the file is not in-repo, then it is probably
     // fine to just silently return null, as the only machines where this is
@@ -34,9 +66,4 @@ export function getLastGitCommitDate(path: string): string {
     // seems low.
     return null;
   }
-
-  // We receive a timestamp in seconds but we need milliseconds
-  const msec = Number.parseInt(result.trim()) * 1000;
-
-  return new Date(msec).toISOString();
 }