[PATCH 0/6] Deprecating "diff-files -q"

The "-q" option given to "git diff-files" is a remnant of the "show-diff" command, the precursor of today's "git diff-files" (back then, we didn't even have "git" potty. The user literally typed "show-diff", not "git show-diff").

ca2a0798 ([PATCH] Add "-q" option to show-diff.c, 2005-04-15) added that option. Back then, we did not have pathspec matching, and we iterated over command line arguments, and required all of them exist as filesystem entities. "-q" was a way to defeat that "you name a file, it must exist in the working tree" safety, and also at the same time not give output for such a file that was removed from the working tree.

These days, the command line parsing infrastructure has changed vastly since "show-diff" days, and the former "safety" is enforced by the generalized revision parser ("is it a path or is it a rev?") code and the "--" delimiter on the command line is the way to defeat it. The latter is done by giving a filtering specification that lack D to the "--diff-filter", e.g. "--diff-filter=ACMRTUB".

This is however a bit cumbersome to type. This miniseries updates the diff-filter mechanism to let you say --diff-filter=d (lowercase) to express that you are interested in the changes in general, but not the changes in the 'D' class (i.e. deletion).

The last step tweaks the command line parser of "git diff-files" (and "git diff" without any object on the command line, which goes to the same codepath) and "git diff --no-index" to notice "-q", warn and then turn it into "--diff-filter=d". We should remove the entire thing at a major version bump, like Git 2.0.

This is still a bit rough, without any documentation updates nor tests.

Junio C Hamano (6):
  diff: pass the whole diff_options to diffcore_apply_filter()
  diff: factor out match_filter()
  diff: preparse --diff-filter string argument
  diff: reject unknown change class given to --diff-filter
  diff: allow lowercase letter to specify what change class to exclude
  diff: deprecate -q option to diff-files

 diff-lib.c      |   8 ++--
 diff-no-index.c |   7 +++-
 diff.c          | 125 ++++++++++++++++++++++++++++++++++++++++++++++----------
 diff.h          |   7 +++-
 4 files changed, 118 insertions(+), 29 deletions(-)