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From: Denton Liu <liu.denton@gmail.com>
To: Git Mailing List <git@vger.kernel.org>
Cc: Junio C Hamano <gitster@pobox.com>
Subject: [PATCH v2 0/4] builtin/diff: learn --merge-base
Date: Thu, 10 Sep 2020 00:32:16 -0700	[thread overview]
Message-ID: <cover.1599723087.git.liu.denton@gmail.com> (raw)
In-Reply-To: <cover.1599332861.git.liu.denton@gmail.com>

The range-notation in `git diff` has been cited as a mistake since diff
compares two endpoints, not whole ranges.[0]  In fact, the ranges seem
to take on the opposite meanings when compared to range notation in
`git log`.

In an effort to reduce the use of range notation as much as possible,
introduce the `--merge-base` flag, slightly modified from a suggestion
by Jonathan Nieder.[1] This flag allows us to replace the first commit
given on the command-line with its merge base between the first and
second commits. This allows us to gently deprecate the `...` form
entirely, although that is left as an exercise to the reader ;)

One additional bonus is that this flag allows the "after" side to be not
just constrained to a commit (like with `...` notation). It can now be
the working tree or the index as well.

The `--merge-base` name isn't very satisfying. If anyone has any better
suggestions, please let me know.

Changes since v1:

* Implement Junio's documentation suggestions

* Update git diff's usage to include this option

[0]: https://lore.kernel.org/git/xmqqy2v26hu0.fsf@gitster-ct.c.googlers.com/
[1]: https://lore.kernel.org/git/20191223215928.GB38316@google.com/

Denton Liu (4):
  t4068: remove unnecessary >tmp
  git-diff.txt: backtick quote command text
  builtin/diff: parse --no-index using parse_options()
  builtin/diff: learn --merge-base

 Documentation/git-diff.txt | 40 +++++++++++-----
 builtin/diff.c             | 94 +++++++++++++++++++++++++++++++++-----
 diff-no-index.c            | 15 ++----
 t/t4068-diff-symmetric.sh  | 89 ++++++++++++++++++++++++++++++++++--
 4 files changed, 198 insertions(+), 40 deletions(-)

Range-diff against v1:
1:  231ba3f661 ! 1:  4f219cf0d1 builtin/diff: learn --merge-base
    @@ Commit message
     
         Suggested-by: Jonathan Nieder <jrnieder@gmail.com>
     
    +
    + ## Notes ##
    +    The `--merge-base` name isn't very satisfying. If anyone has any
    +    suggestions for alternative names, please let me know.
    +
      ## Documentation/git-diff.txt ##
     @@ Documentation/git-diff.txt: SYNOPSIS
      'git diff' [<options>] [<commit>] [--] [<path>...]
    @@ Documentation/git-diff.txt: files on disk.
     +equivalent to `git diff $(git merge-base A B) B`.
     ++
     +In the case where one commit is given, a diff is displayed between the
    -+merge base and the working tree or the index if `--cached` is given.
    -+`git diff --merge-base A` is equivalent to `git diff $(git merge-base A
    -+HEAD)`.
    ++merge base of the commit and the HEAD and the working tree or the index
    ++if `--cached` is given. `git diff --merge-base A` is equivalent to `git
    ++diff $(git merge-base A HEAD)`.
     ++
     +In the case where no commits are given, this form behaves identically to
     +as if no `--merge-base` were supplied.
    @@ builtin/diff.c
      
      #define DIFF_NO_INDEX_EXPLICIT 1
      #define DIFF_NO_INDEX_IMPLICIT 2
    +@@ builtin/diff.c: static const char builtin_diff_usage[] =
    + "git diff [<options>] [<commit>] [--] [<path>...]\n"
    + "   or: git diff [<options>] --cached [<commit>] [--] [<path>...]\n"
    + "   or: git diff [<options>] <commit> [<commit>...] <commit> [--] [<path>...]\n"
    +-"   or: git diff [<options>] <commit>...<commit>] [--] [<path>...]\n"
    ++"   or: git diff [<options>] --merge-base [<commit> [<commit>]] [--] [<path>...]\n"
    + "   or: git diff [<options>] <blob> <blob>]\n"
    + "   or: git diff [<options>] --no-index [--] <path> <path>]\n"
    + COMMON_DIFF_OPTIONS_HELP;
     @@ builtin/diff.c: int cmd_diff(int argc, const char **argv, const char *prefix)
      	int blobs = 0, paths = 0;
      	struct object_array_entry *blob[2];
    @@ builtin/diff.c: int cmd_diff(int argc, const char **argv, const char *prefix)
      			   DIFF_NO_INDEX_EXPLICIT,
      			   PARSE_OPT_NONEG),
     +		OPT_BOOL(0, "merge-base", &merge_base,
    -+			 N_("use the merge base between the two commits as the diff base")),
    ++			 N_("compare with the merge base between two commits")),
      		OPT_END(),
      	};
      
-- 
2.28.0.618.gf4bc123cb7


  parent reply	other threads:[~2020-09-10  7:33 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-05 19:08 [PATCH " Denton Liu
2020-09-05 19:08 ` [PATCH 1/4] t4068: remove unnecessary >tmp Denton Liu
2020-09-05 19:08 ` [PATCH 2/4] git-diff.txt: backtick quote command text Denton Liu
2020-09-05 19:08 ` [PATCH 3/4] builtin/diff: parse --no-index using parse_options() Denton Liu
2020-09-05 19:08 ` [PATCH 4/4] builtin/diff: learn --merge-base Denton Liu
2020-09-06 21:58   ` Junio C Hamano
2020-09-10  7:32 ` Denton Liu [this message]
2020-09-10  7:32   ` [PATCH v2 1/4] t4068: remove unnecessary >tmp Denton Liu
2020-09-10  7:32   ` [PATCH v2 2/4] git-diff.txt: backtick quote command text Denton Liu
2020-09-10  7:32   ` [PATCH v2 3/4] builtin/diff: parse --no-index using parse_options() Denton Liu
2020-09-10 18:35     ` Junio C Hamano
2020-09-13  8:31       ` Denton Liu
2020-09-13 21:45         ` Junio C Hamano
2020-09-10  7:32   ` [PATCH v2 4/4] builtin/diff: learn --merge-base Denton Liu
2020-09-17  7:44   ` [PATCH v3 00/10] " Denton Liu
2020-09-17  7:44     ` [PATCH v3 01/10] t4068: remove unnecessary >tmp Denton Liu
2020-09-17  7:44     ` [PATCH v3 02/10] git-diff-index.txt: make --cached description a proper sentence Denton Liu
2020-09-17  7:44     ` [PATCH v3 03/10] git-diff.txt: backtick quote command text Denton Liu
2020-09-17  7:44     ` [PATCH v3 04/10] contrib/completion: extract common diff/difftool options Denton Liu
2020-09-17  7:44     ` [PATCH v3 05/10] diff-lib: accept option flags in run_diff_index() Denton Liu
2020-09-17 17:00       ` Junio C Hamano
2020-09-17  7:44     ` [PATCH v3 06/10] diff-lib: define diff_get_merge_base() Denton Liu
2020-09-17 17:16       ` Junio C Hamano
2020-09-18 10:34         ` Denton Liu
2020-09-19  0:33           ` Junio C Hamano
2020-09-17  7:44     ` [PATCH v3 07/10] t4068: add --merge-base tests Denton Liu
2020-09-17  7:44     ` [PATCH v3 08/10] builtin/diff-index: learn --merge-base Denton Liu
2020-09-17 17:28       ` Junio C Hamano
2020-09-17 18:13         ` Jeff King
2020-09-18  5:11           ` Junio C Hamano
2020-09-18 18:12             ` Jeff King
2020-09-17  7:44     ` [PATCH v3 09/10] builtin/diff-tree: " Denton Liu
2020-09-17 18:23       ` Junio C Hamano
2020-09-18 10:48         ` Denton Liu
2020-09-18 16:52           ` Junio C Hamano
2020-09-20 11:01             ` Denton Liu
2020-09-21 16:05               ` Junio C Hamano
2020-09-21 17:27                 ` Denton Liu
2020-09-21 21:09                   ` Junio C Hamano
2020-09-21 21:19                     ` Junio C Hamano
2020-09-21 21:54                     ` Denton Liu
2020-09-21 22:18                       ` Junio C Hamano
2020-09-23  9:47                         ` Denton Liu
2020-09-25 21:02                           ` Junio C Hamano
2020-09-26  1:52                             ` Denton Liu
2020-09-17  7:44     ` [PATCH v3 10/10] contrib/completion: complete `git diff --merge-base` Denton Liu
2020-09-20 11:22     ` [PATCH v4 00/10] builtin/diff: learn --merge-base Denton Liu
2020-09-20 11:22       ` [PATCH v4 01/10] t4068: remove unnecessary >tmp Denton Liu
2020-09-20 11:22       ` [PATCH v4 02/10] git-diff-index.txt: make --cached description a proper sentence Denton Liu
2020-09-20 11:22       ` [PATCH v4 03/10] git-diff.txt: backtick quote command text Denton Liu
2020-09-20 11:22       ` [PATCH v4 04/10] contrib/completion: extract common diff/difftool options Denton Liu
2020-09-20 11:22       ` [PATCH v4 05/10] diff-lib: accept option flags in run_diff_index() Denton Liu
2020-09-20 11:22       ` [PATCH v4 06/10] diff-lib: define diff_get_merge_base() Denton Liu
2020-09-20 11:22       ` [PATCH v4 07/10] t4068: add --merge-base tests Denton Liu
2020-09-20 11:22       ` [PATCH v4 08/10] builtin/diff-index: learn --merge-base Denton Liu
2020-09-29 19:53         ` Martin Ågren
2020-09-20 11:22       ` [PATCH v4 09/10] builtin/diff-tree: " Denton Liu
2020-09-20 11:22       ` [PATCH v4 10/10] contrib/completion: complete `git diff --merge-base` Denton Liu

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