convert: treat an empty string for clean/smudge filters as "cat"

Once a lower-priority configuration file defines a clean or smudge
filter, there is no convenient way to override it to produce as-is
output.  Even though the configuration mechanism implements "the
last one wins" semantics, you cannot set them to an empty string and
expect them to work, as apply_filter() would try to run the empty
string as an external command and fail.  The conversion is not done,
but the function would still report a failure to convert.

Even though resetting the variable to "cat" (i.e. pass the data back
as-is and report success) is an obvious and a viable way to solve
this, it is wasteful to spawn an external process just as a
workaround.

Instead, teach apply_filter() to treat an empty string as a no-op
filter that always returns successfully its input as-is without
conversion.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Lars Schneider 2016-01-29 09:21:37 +01:00 коммит произвёл Junio C Hamano
Родитель 1b0b6dd072
Коммит 1a8630dc3b
2 изменённых файлов: 17 добавлений и 1 удалений

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@ -395,7 +395,7 @@ static int apply_filter(const char *path, const char *src, size_t len, int fd,
struct async async;
struct filter_params params;
if (!cmd)
if (!cmd || !*cmd)
return 0;
if (!dst)

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@ -252,4 +252,20 @@ test_expect_success "filter: smudge empty file" '
test_cmp expected filtered-empty-in-repo
'
test_expect_success 'disable filter with empty override' '
test_config_global filter.disable.smudge false &&
test_config_global filter.disable.clean false &&
test_config filter.disable.smudge false &&
test_config filter.disable.clean false &&
echo "*.disable filter=disable" >.gitattributes &&
echo test >test.disable &&
git -c filter.disable.clean= add test.disable 2>err &&
test_must_be_empty err &&
rm -f test.disable &&
git -c filter.disable.smudge= checkout -- test.disable 2>err &&
test_must_be_empty err
'
test_done