Validate Change-Id usage via test driver

Commit d93a203 mandates that each commit include a Change-Id. However,
commits created via the GitHub web interface may omit this identifier,
contrary to the best practices outlined in the lecture assignments.

This commit enforces the test driver to traverse the commit history and
ensure every commit message contains a valid Change-Id.

Change-Id: I3ec19076388f6b69081368b81b5f8b7eaa45e569

Author: jserv

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                 "FATAL: The repository is outdated.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