Merge pull request libgit2#6244 from jorio/fix-diff_delta_format_path-crash

Fix crash when regenerating a patch with unquoted spaces in filename

Author: ethomson

src/libgit2/diff_print.c

@@ -316,6 +316,11 @@ static int diff_print_oid_range(
 static int diff_delta_format_path(
 	git_str *out, const char *prefix, const char *filename)
 {
+	if (!filename) {
+		/* don't prefix "/dev/null" */
+ 		return git_str_puts(out, "/dev/null");
+	}
+
 	if (git_str_joinpath(out, prefix, filename) < 0)
 		return -1;
 

tests/libgit2/diff/parse.c

@@ -431,6 +431,32 @@ void test_diff_parse__new_file_with_space(void)
 	git_diff_free(diff);
 }
 
+void test_diff_parse__new_file_with_space_and_regenerate_patch(void)
+{
+	const char *content = PATCH_ORIGINAL_NEW_FILE_WITH_SPACE;
+	git_diff *diff = NULL;
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_diff_from_buffer(&diff, content, strlen(content)));
+	cl_git_pass(git_diff_to_buf(&buf, diff, GIT_DIFF_FORMAT_PATCH));
+
+	git_buf_dispose(&buf);
+	git_diff_free(diff);
+}
+
+void test_diff_parse__delete_file_with_space_and_regenerate_patch(void)
+{
+	const char *content = PATCH_DELETE_FILE_WITH_SPACE;
+	git_diff *diff = NULL;
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_diff_from_buffer(&diff, content, strlen(content)));
+	cl_git_pass(git_diff_to_buf(&buf, diff, GIT_DIFF_FORMAT_PATCH));
+
+	git_buf_dispose(&buf);
+	git_diff_free(diff);
+}
+
 void test_diff_parse__crlf(void)
 {
 	const char *text = PATCH_CRLF;

tests/libgit2/patch/patch_common.h

@@ -933,6 +933,15 @@
 	"@@ -0,0 +1 @@\n" \
 	"+a\n"
 
+#define PATCH_DELETE_FILE_WITH_SPACE \
+	"diff --git a/sp ace.txt b/sp ace.txt\n" \
+	"deleted file mode 100644\n" \
+	"index 789819226..000000000\n" \
+	"--- a/sp ace.txt\n" \
+	"+++ /dev/null\n" \
+	"@@ -1 +0,0 @@\n" \
+	"-a\n"
+
 #define PATCH_CRLF \
 	"diff --git a/test-file b/test-file\r\n" \
 	"new file mode 100644\r\n" \