fsck: fix bogus commit header check

daae192 (fsck: check ident lines in commit objects, 2010-04-24)
taught fsck to expect commit objects to have the form

  tree <object name>
  <parents>
  author <valid ident string>
  committer <valid ident string>

  log message

The check is overly strict: for example, it errors out with the
message “expected blank line” for perfectly valid commits with an
"encoding ISO-8859-1" line.

Later it might make sense to teach fsck about the rest of the header
and warn about unrecognized header lines, but for simplicity, let’s
accept arbitrary trailing lines for now.

Reported-by: Tuncer Ayaz <tuncer.ayaz@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fsck.c

@@ -311,8 +311,6 @@ static int fsck_commit(struct commit *commit, fsck_error error_func)
 	err = fsck_ident(&buffer, &commit->object, error_func);
 	if (err)
 		return err;
-	if (*buffer != '\n')
-		return error_func(&commit->object, FSCK_ERROR, "invalid format - expected blank line");
 	if (!commit->tree)
 		return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
 

t/t1450-fsck.sh

@@ -5,7 +5,9 @@ test_description='git fsck random collection of tests'
 . ./test-lib.sh
 
 test_expect_success setup '
+	git config i18n.commitencoding ISO-8859-1 &&
 	test_commit A fileA one &&
+	git config --unset i18n.commitencoding &&
 	git checkout HEAD^0 &&
 	test_commit B fileB two &&
 	git tag -d A B &&
@@ -28,6 +30,12 @@ test_expect_success 'loose objects borrowed from alternate are not missing' '
 	)
 '
 
+test_expect_success 'valid objects appear valid' '
+	{ git fsck 2>out; true; } &&
+	! grep error out &&
+	! grep fatal out
+'
+
 # Corruption tests follow.  Make sure to remove all traces of the
 # specific corruption you test afterwards, lest a later test trip over
 # it.