The left and right base directories were pointed to the buf field of two strbufs, which were subject to change.
A contrived test case shows the problem where a file with a long enough name to force the strbuf to grow is up-to-date (hence the code path is used where the work tree's version of the file is reused), and then a file that is not up-to-date needs to be written (hence the code path is used where checkout_entry() uses the previously recorded base_dir that is invalid by now). Let's just copy the base_dir strings for use with checkout_entry(), never touch them until the end, and release them then. This is an easily verifiable fix (as opposed to the next-obvious alternative: to re-set base_dir after every loop iteration). This fixes https://github.com/git-for-windows/git/issues/1124 Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de> --- builtin/difftool.c | 7 +++++-- t/t7800-difftool.sh | 19 +++++++++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/builtin/difftool.c b/builtin/difftool.c index 25e54ad3edb..568294aac01 100644 --- a/builtin/difftool.c +++ b/builtin/difftool.c @@ -305,6 +305,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix, struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT; struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT; struct strbuf wtdir = STRBUF_INIT; + char *lbase_dir, *rbase_dir; size_t ldir_len, rdir_len, wtdir_len; struct cache_entry *ce = xcalloc(1, sizeof(ce) + PATH_MAX + 1); const char *workdir, *tmp; @@ -339,11 +340,11 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix, memset(&wtindex, 0, sizeof(wtindex)); memset(&lstate, 0, sizeof(lstate)); - lstate.base_dir = ldir.buf; + lstate.base_dir = lbase_dir = xstrdup(ldir.buf); lstate.base_dir_len = ldir.len; lstate.force = 1; memset(&rstate, 0, sizeof(rstate)); - rstate.base_dir = rdir.buf; + rstate.base_dir = rbase_dir = xstrdup(rdir.buf); rstate.base_dir_len = rdir.len; rstate.force = 1; @@ -626,6 +627,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix, finish: free(ce); + free(lbase_dir); + free(rbase_dir); strbuf_release(&ldir); strbuf_release(&rdir); strbuf_release(&wtdir); diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh index 0e7f30db2d9..7f09867478c 100755 --- a/t/t7800-difftool.sh +++ b/t/t7800-difftool.sh @@ -393,6 +393,25 @@ test_expect_success 'setup change in subdirectory' ' git commit -m "modified both" ' +test_expect_success 'difftool -d with growing paths' ' + a=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa && + git init growing && + ( + cd growing && + echo "test -f \"\$2/b\"" | write_script .git/test-for-b.sh && + one=$(printf 1 | git hash-object -w --stdin) && + two=$(printf 2 | git hash-object -w --stdin) && + git update-index --add \ + --cacheinfo 100644,$one,$a --cacheinfo 100644,$two,b && + tree1=$(git write-tree) && + git update-index --add \ + --cacheinfo 100644,$two,$a --cacheinfo 100644,$one,b && + tree2=$(git write-tree) && + git checkout -- $a && + git difftool -d --extcmd .git/test-for-b.sh $tree1 $tree2 + ) +' + run_dir_diff_test () { test_expect_success "$1 --no-symlinks" " symlinks=--no-symlinks && -- 2.12.2.windows.2.1.g7df5db8d31e
