lib-fs: fs-metawrap - Don't try to write to an already finished ostream

Fixes a crash after recent changes when trying to write an empty file via
fs-metawrap.

diff --git a/src/lib-fs/fs-metawrap.c b/src/lib-fs/fs-metawrap.c
index ae99da3f58096a0193ebd54a31619cf334d6199b..c62b9694acfb28755b903a7a191e93fa75544ec4 100644 (file)
--- a/src/lib-fs/fs-metawrap.c
+++ b/src/lib-fs/fs-metawrap.c
@@ -391,10 +391,16 @@ static int fs_metawrap_write_stream_finish(struct fs_file *_file, bool success)
        }
        /* finish writing the temporary file */
        if (file->temp_output->offset == 0) {
-               /* empty file */
-               fs_metawrap_write_metadata_to(file, file->temp_output);
+               /* empty file - temp_output is already finished,
+                  so we can't write to it. */
+               string_t *str = t_str_new(128);
+
+               o_stream_destroy(&file->temp_output);
+               fs_metawrap_append_metadata(file, str);
+               input = i_stream_create_copy_from_data(str_data(str), str_len(str));
+       } else {
+               input = iostream_temp_finish(&file->temp_output, IO_BLOCK_SIZE);
        }
-       input = iostream_temp_finish(&file->temp_output, IO_BLOCK_SIZE);
        if (file->metadata_changed_since_write) {
                /* we'll need to recreate the metadata. do this by creating a
                   new istream combining the new metadata header and the