2.36 format-patch regression fix
e900d494dc (diff: add an API for deferred freeing, 2021-02-11) added a way to allow reusing diffopts: the no_free bit. 244c27242f (diff.[ch]: have diff_free() call clear_pathspec(opts.pathspec), 2022-02-16) made that mechanism mandatory. git format-patch only sets no_free when --output is given, causing it to forget pathspecs after the first commit. Set no_free unconditionally instead. The existing test was unable to detect this breakage because it checks stderr for the absence of a certain string, but format-patch writes to stdout. Also the test was not checking the case of one commit modifying multiple files and a pathspec limiting the diff. Replace it with a more thorough one. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>