Merge pull request libgit2#4447 from pks-t/pks/diff-file-contents-refcount-blob

diff_file: properly refcount blobs when initializing file contents

Author: ethomson

src/diff_file.c

@@ -139,7 +139,6 @@ int git_diff_file_content__init_from_src(
 	memset(fc, 0, sizeof(*fc));
 	fc->repo = repo;
 	fc->file = as_file;
-	fc->blob = src->blob;
 
 	if (!src->blob && !src->buf) {
 		fc->flags |= GIT_DIFF_FLAG__NO_DATA;
@@ -149,12 +148,15 @@ int git_diff_file_content__init_from_src(
 		fc->file->mode = GIT_FILEMODE_BLOB;
 
 		if (src->blob) {
+			git_blob_dup((git_blob **)&fc->blob, (git_blob *) src->blob);
 			fc->file->size = git_blob_rawsize(src->blob);
 			git_oid_cpy(&fc->file->id, git_blob_id(src->blob));
 			fc->file->id_abbrev = GIT_OID_HEXSZ;
 
 			fc->map.len  = (size_t)fc->file->size;
 			fc->map.data = (char *)git_blob_rawcontent(src->blob);
+
+			fc->flags |= GIT_DIFF_FLAG__FREE_BLOB;
 		} else {
 			fc->file->size = src->buflen;
 			git_odb_hash(&fc->file->id, src->buf, src->buflen, GIT_OBJ_BLOB);

tests/diff/blob.c

@@ -1,6 +1,19 @@
 #include "clar_libgit2.h"
 #include "diff_helpers.h"
 
+#define BLOB_DIFF \
+    "diff --git a/file b/file\n" \
+    "index 45141a7..4d713dc 100644\n" \
+    "--- a/file\n" \
+    "+++ b/file\n" \
+    "@@ -1 +1,6 @@\n" \
+    " Hello from the root\n" \
+    "+\n" \
+    "+Some additional lines\n" \
+    "+\n" \
+    "+Down here below\n" \
+    "+\n"
+
 static git_repository *g_repo = NULL;
 static diff_expects expected;
 static git_diff_options opts;
@@ -65,6 +78,32 @@ static void assert_one_modified(
 	cl_assert_equal_i(dels,  exp->line_dels);
 }
 
+void test_diff_blob__patch_with_freed_blobs(void)
+{
+	git_oid a_oid, b_oid;
+	git_blob *a, *b;
+	git_patch *p;
+	git_buf buf = GIT_BUF_INIT;
+
+	/* tests/resources/attr/root_test1 */
+	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 4));
+	/* tests/resources/attr/root_test2 */
+	cl_git_pass(git_oid_fromstrn(&b_oid, "4d713dc4", 8));
+	cl_git_pass(git_blob_lookup_prefix(&b, g_repo, &b_oid, 4));
+
+	cl_git_pass(git_patch_from_blobs(&p, a, NULL, b, NULL, NULL));
+
+	git_blob_free(a);
+	git_blob_free(b);
+
+	cl_git_pass(git_patch_to_buf(&buf, p));
+	cl_assert_equal_s(buf.ptr, BLOB_DIFF);
+
+	git_patch_free(p);
+	git_buf_free(&buf);
+}
+
 void test_diff_blob__can_compare_text_blobs(void)
 {
 	git_blob *a, *b, *c;