entry: fix leaking pathnames during delayed checkout

When filtering files during delayed checkout, we pass a string list to
`async_query_available_blobs()`. This list is initialized with NODUP,
and thus inserted strings will not be owned by the list. In the latter
function we then try to hand over ownership by passing an `xstrup()`'d
value to `string_list_insert()`. But this is not how this works: a NODUP
list does not take ownership of allocated strings and will never free
them for the caller.

Fix this issue by initializing the list as `DUP` instead and dropping
the explicit call to `xstrdup()`. This is okay to do given that this is
the single callsite of `async_query_available_blobs()`.

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

Author: pks-t

convert.c

@@ -960,7 +960,7 @@ int async_query_available_blobs(const char *cmd, struct string_list *available_p
 	while ((line = packet_read_line(process->out, NULL))) {
 		const char *path;
 		if (skip_prefix(line, "pathname=", &path))
-			string_list_insert(available_paths, xstrdup(path));
+			string_list_insert(available_paths, path);
 		else
 			; /* ignore unknown keys */
 	}

entry.c

@@ -191,7 +191,7 @@ int finish_delayed_checkout(struct checkout *state, int show_progress)
 		progress = start_delayed_progress(_("Filtering content"), dco->paths.nr);
 	while (dco->filters.nr > 0) {
 		for_each_string_list_item(filter, &dco->filters) {
-			struct string_list available_paths = STRING_LIST_INIT_NODUP;
+			struct string_list available_paths = STRING_LIST_INIT_DUP;
 
 			if (!async_query_available_blobs(filter->string, &available_paths)) {
 				/* Filter reported an error */
@@ -245,6 +245,8 @@ int finish_delayed_checkout(struct checkout *state, int show_progress)
 				} else
 					errs = 1;
 			}
+
+			string_list_clear(&available_paths, 0);
 		}
 
 		filter_string_list(&dco->filters, 0, string_is_not_null, NULL);

t/t2080-parallel-checkout-basics.sh

@@ -8,6 +8,7 @@ working tree.
 '
 
 TEST_NO_CREATE_REPO=1
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-parallel-checkout.sh"
 

t/t2082-parallel-checkout-attributes.sh

@@ -10,6 +10,7 @@ properly (without access to the index or attribute stack).
 '
 
 TEST_NO_CREATE_REPO=1
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-parallel-checkout.sh"
 . "$TEST_DIRECTORY/lib-encoding.sh"