Commit de590550172c68bf374f9d12636b06295c5fe048
2013-01-08T17:11:11
Resolve crash with diff against empty file It is not legal inside our `p_mmap` function to mmap a zero length file. This adds a test that exercises that case inside diff and fixes the code path where we would try to do that. The fix turns out not to be a lot of code since our default file content is already initialized to "" which works in this case. Fixes #1210
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diff --git a/src/diff_output.c b/src/diff_output.c
index e80cfaa..f98665d 100644
--- a/src/diff_output.c
+++ b/src/diff_output.c
@@ -376,6 +376,9 @@ static int get_workdir_content(
goto close_and_cleanup;
if (error == 0) { /* note: git_filters_load returns filter count */
+ if (!file->size)
+ goto close_and_cleanup;
+
error = git_futils_mmap_ro(map, fd, 0, (size_t)file->size);
file->flags |= GIT_DIFF_FILE_UNMAP_DATA;
} else {
diff --git a/src/fileops.c b/src/fileops.c
index f2b6b01..23cb07e 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -121,7 +121,7 @@ mode_t git_futils_canonical_mode(mode_t raw_mode)
int git_futils_readbuffer_fd(git_buf *buf, git_file fd, size_t len)
{
- ssize_t read_size;
+ ssize_t read_size = 0;
git_buf_clear(buf);
diff --git a/tests-clar/diff/workdir.c b/tests-clar/diff/workdir.c
index 1b1b616..5c89b95 100644
--- a/tests-clar/diff/workdir.c
+++ b/tests-clar/diff/workdir.c
@@ -881,3 +881,46 @@ void test_diff_workdir__checks_options_version(void)
err = giterr_last();
cl_assert_equal_i(GITERR_INVALID, err->klass);
}
+
+void test_diff_workdir__can_diff_empty_file(void)
+{
+ git_diff_list *diff;
+ git_tree *tree;
+ git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+ struct stat st;
+ git_diff_patch *patch;
+
+ g_repo = cl_git_sandbox_init("attr_index");
+
+ tree = resolve_commit_oid_to_tree(g_repo, "3812cfef3661"); /* HEAD */
+
+ /* baseline - make sure there are no outstanding diffs */
+
+ cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, tree, &opts));
+ cl_assert_equal_i(2, (int)git_diff_num_deltas(diff));
+ git_diff_list_free(diff);
+
+ /* empty contents of file */
+
+ cl_git_rewritefile("attr_index/README.txt", "");
+ cl_git_pass(git_path_lstat("attr_index/README.txt", &st));
+ cl_assert_equal_i(0, (int)st.st_size);
+
+ cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, tree, &opts));
+ cl_assert_equal_i(3, (int)git_diff_num_deltas(diff));
+ /* diffs are: .gitattributes, README.txt, sub/sub/.gitattributes */
+ cl_git_pass(git_diff_get_patch(&patch, NULL, diff, 1));
+ git_diff_patch_free(patch);
+ git_diff_list_free(diff);
+
+ /* remove a file altogether */
+
+ cl_git_pass(p_unlink("attr_index/README.txt"));
+ cl_assert(!git_path_exists("attr_index/README.txt"));
+
+ cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, tree, &opts));
+ cl_assert_equal_i(3, (int)git_diff_num_deltas(diff));
+ cl_git_pass(git_diff_get_patch(&patch, NULL, diff, 1));
+ git_diff_patch_free(patch);
+ git_diff_list_free(diff);
+}