reftable/stack: adjust permissions of compacted tables

When creating a new compacted table from a range of preexisting ones we
don't set the default permissions on the resulting table when specified
by the user. This has the effect that the "core.sharedRepository" config
will not be honored correctly.

Fix this bug and add a test to catch this issue. Note that we only test
on non-Windows platforms because Windows does not use POSIX permissions
natively.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

reftable/stack.c

@@ -731,6 +731,12 @@ static int stack_compact_locked(struct reftable_stack *st, int first, int last,
 	strbuf_addstr(temp_tab, ".temp.XXXXXX");
 
 	tab_fd = mkstemp(temp_tab->buf);
+	if (st->config.default_permissions &&
+	    chmod(temp_tab->buf, st->config.default_permissions) < 0) {
+		err = REFTABLE_IO_ERROR;
+		goto done;
+	}
+
 	wr = reftable_new_writer(reftable_fd_write, &tab_fd, &st->config);
 
 	err = stack_write_compact(st, wr, first, last, config);

reftable/stack_test.c

@@ -443,15 +443,16 @@ static void test_reftable_stack_add(void)
 	int err = 0;
 	struct reftable_write_options cfg = {
 		.exact_log_message = 1,
+		.default_permissions = 0660,
 	};
 	struct reftable_stack *st = NULL;
 	char *dir = get_tmp_dir(__LINE__);
-
 	struct reftable_ref_record refs[2] = { { NULL } };
 	struct reftable_log_record logs[2] = { { NULL } };
+	struct strbuf path = STRBUF_INIT;
+	struct stat stat_result;
 	int N = ARRAY_SIZE(refs);
 
-
 	err = reftable_new_stack(&st, dir, cfg);
 	EXPECT_ERR(err);
 	st->disable_auto_compact = 1;
@@ -509,12 +510,32 @@ static void test_reftable_stack_add(void)
 		reftable_log_record_release(&dest);
 	}
 
+#ifndef GIT_WINDOWS_NATIVE
+	strbuf_addstr(&path, dir);
+	strbuf_addstr(&path, "/tables.list");
+	err = stat(path.buf, &stat_result);
+	EXPECT(!err);
+	EXPECT((stat_result.st_mode & 0777) == cfg.default_permissions);
+
+	strbuf_reset(&path);
+	strbuf_addstr(&path, dir);
+	strbuf_addstr(&path, "/");
+	/* do not try at home; not an external API for reftable. */
+	strbuf_addstr(&path, st->readers[0]->name);
+	err = stat(path.buf, &stat_result);
+	EXPECT(!err);
+	EXPECT((stat_result.st_mode & 0777) == cfg.default_permissions);
+#else
+	(void) stat_result;
+#endif
+
 	/* cleanup */
 	reftable_stack_destroy(st);
 	for (i = 0; i < N; i++) {
 		reftable_ref_record_release(&refs[i]);
 		reftable_log_record_release(&logs[i]);
 	}
+	strbuf_release(&path);
 	clear_dir(dir);
 }