archive: simplify archive format guessing
The code to guess an output archive's format consumed any --format
options and built a new one. Jonathan noticed that it does so in an
unsafe way, risking to overflow the static buffer fmt_opt.
Change the code to keep the existing --format options intact and to only
add a new one if a format could be guessed based on the output file name.
The new option is added as the first one, allowing the existing ones to
overrule it, i.e. explicit --format options given on the command line win
over format guesses, as before.
To simplify the code further, format_from_name() is changed to return the
full --format option, thus no potentially dangerous sprintf() calls are
needed any more.
Reported-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index 0037f63..27bfba5 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -189,6 +189,16 @@
'git archive --format=zip --output=d2.zip HEAD &&
test_cmp d.zip d2.zip'
+test_expect_success 'git archive with --output, inferring format' '
+ git archive --output=d3.zip HEAD &&
+ test_cmp d.zip d3.zip
+'
+
+test_expect_success 'git archive with --output, override inferred format' '
+ git archive --format=tar --output=d4.zip HEAD &&
+ test_cmp b.tar d4.zip
+'
+
$UNZIP -v >/dev/null 2>&1
if [ $? -eq 127 ]; then
say "Skipping ZIP tests, because unzip was not found"
