userdiff: skip textconv caching when not in a repository

The textconv caching system uses git-notes to store its cache entries.
But if you're using "diff --no-index" outside of a repository, then
obviously that isn't going to work.

Since caching is just an optimization, it's OK for us to skip it.
However, the current behavior is much worse: we call notes_cache_init()
which tries to look up the ref, and the low-level ref code hits a BUG(),
killing the program. Instead, we should notice before setting up the
cache that it there's no repository, and just silently skip it.

Reported-by: Paweł Dominiak <dominiak.pawel@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t4042-diff-textconv-caching.sh b/t/t4042-diff-textconv-caching.sh
index bf33aedf4b22868fd820330a460965d27e66cb91..8ebfa3c1be2fec46558c739fd3ccda37a952c225 100755 (executable)
--- a/t/t4042-diff-textconv-caching.sh
+++ b/t/t4042-diff-textconv-caching.sh
@@ -118,4 +118,26 @@ test_expect_success 'log notes cache and still use cache for -p' '
        git log --no-walk -p refs/notes/textconv/magic HEAD
 '
 
+test_expect_success 'caching is silently ignored outside repo' '
+       mkdir -p non-repo &&
+       echo one >non-repo/one &&
+       echo two >non-repo/two &&
+       echo "* diff=test" >attr &&
+       test_expect_code 1 \
+       nongit git -c core.attributesFile="$PWD/attr" \
+                  -c diff.test.textconv="tr a-z A-Z <" \
+                  -c diff.test.cachetextconv=true \
+                  diff --no-index one two >actual &&
+       cat >expect <<-\EOF &&
+       diff --git a/one b/two
+       index 5626abf..f719efd 100644
+       --- a/one
+       +++ b/two
+       @@ -1 +1 @@
+       -ONE
+       +TWO
+       EOF
+       test_cmp expect actual
+'
+
 test_done

diff --git a/userdiff.c b/userdiff.c
index e399543823bdf2c0c8f24fb87f7622ac4d8a366b..fce3a31efaba34dd8a77899abf8b56b690e9af71 100644 (file)
--- a/userdiff.c
+++ b/userdiff.c
@@ -3,6 +3,7 @@
 #include "userdiff.h"
 #include "attr.h"
 #include "strbuf.h"
+#include "environment.h"
 
 static struct userdiff_driver *drivers;
 static int ndrivers;
@@ -460,7 +461,8 @@ struct userdiff_driver *userdiff_get_textconv(struct repository *r,
        if (!driver->textconv)
                return NULL;
 
-       if (driver->textconv_want_cache && !driver->textconv_cache) {
+       if (driver->textconv_want_cache && !driver->textconv_cache &&
+           have_git_dir()) {
                struct notes_cache *c = xmalloc(sizeof(*c));
                struct strbuf name = STRBUF_INIT;