Validate Change-Id usage via test driver

qtest.c

@@ -1252,7 +1252,7 @@ bool commit_exists(const char *commit_hash)
     close(pipefd[1]);
 
     FILE *stream = fdopen(pipefd[0], "r");
-    if (stream == NULL) {
+    if (!stream) {
         /* Error converting file descriptor to stream */
         perror("fdopen");
         return false;
@@ -1276,6 +1276,26 @@ bool commit_exists(const char *commit_hash)
     return found;
 }
 
+static bool check_commitlog(void)
+{
+    pid_t pid;
+    int status;
+    char *script_path = "scripts/check-commitlog.sh";
+    char *argv[] = {script_path, NULL};
+
+    int spawn_ret = posix_spawnp(&pid, script_path, NULL, NULL, argv, environ);
+    if (spawn_ret != 0)
+        return false;
+
+    if (waitpid(pid, &status, 0) == -1)
+        return false;
+
+    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+        return false;
+
+    return true;
+}
+
 #define GIT_HOOK ".git/hooks/"
 static bool sanity_check()
 {
@@ -1314,6 +1334,14 @@ static bool sanity_check()
                 "FATAL: The repository is outdated. Please update properly.\n");
             return false;
         }
+        if (!check_commitlog()) {
+            fprintf(stderr, "FATAL: The git commit history is chaotic.\n");
+            fprintf(stderr,
+                    "Please install the required git hooks per the assignment "
+                    "instructions and make your commits from the terminal "
+                    "instead of using the GitHub web interface.\n");
+            return false;
+        }
     }
 
     return true;

scripts/check-commitlog.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# Check that every non-merge commit after the specified base commit has a commit
+# message ending with a valid Change-Id line. A valid Change-Id line must be the
+# last non-empty line of the commit message and follow the format:
+#
+#   Change-Id: I<hexadecimal_hash>
+#
+# Merge commits are excluded from this check.
+
+# Base commit from which to start checking.
+BASE_COMMIT="0b8be2c15160c216e8b6ec82c99a000e81c0e429"
+
+# Get a list of non-merge commit hashes after BASE_COMMIT.
+commits=$(git rev-list --no-merges "${BASE_COMMIT}"..HEAD)
+
+failed=0
+
+for commit in $commits; do
+  # Retrieve the commit message for the given commit.
+  commit_msg=$(git log -1 --format=%B "${commit}")
+
+  # Extract the last non-empty line from the commit message.
+  last_line=$(echo "$commit_msg" | awk 'NF {line=$0} END {print line}')
+
+  # Check if the last line matches the expected Change-Id format.
+  if [[ ! $last_line =~ ^Change-Id:\ I[0-9a-fA-F]+$ ]]; then
+    subject=$(git log -1 --format=%s "${commit}")
+    short_hash=$(git rev-parse --short "${commit}")
+    echo "Commit ${short_hash} with subject '$subject' does not end with a valid Change-Id."
+    failed=1
+  fi
+done
+
+if [ $failed -ne 0 ]; then
+  echo
+  echo "Some commits are missing a valid Change-Id. Please amend the commit messages accordingly."
+  echo
+  exit 1
+fi
+
+exit 0

scripts/checksums

@@ -1,2 +1,3 @@
 db6784ff3917888db4d1dceaa0570d99ed40e762  queue.h
 bfb6df45d64356868c86a7173455d39970bd0270  list.h
+3bb0192cee08d165fd597a9f6fbb404533e28fcf  scripts/check-commitlog.sh