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 Changes since v2: * Teach diff-index and diff-tree the --merge-base option as well [0]: https://lore.kernel.org/git/xmqqy2v26hu0.fsf@xxxxxxxxxxxxxxxxxxxxxxxxx/ [1]: https://lore.kernel.org/git/20191223215928.GB38316@xxxxxxxxxx/ Denton Liu (10): t4068: remove unnecessary >tmp git-diff-index.txt: make --cached description a proper sentence git-diff.txt: backtick quote command text contrib/completion: extract common diff/difftool options diff-lib: accept option flags in run_diff_index() diff-lib: define diff_get_merge_base() t4068: add --merge-base tests builtin/diff-index: learn --merge-base builtin/diff-tree: learn --merge-base contrib/completion: complete `git diff --merge-base` Documentation/git-diff-index.txt | 9 +- Documentation/git-diff-tree.txt | 7 +- Documentation/git-diff.txt | 37 +++-- builtin/diff-index.c | 10 +- builtin/diff-tree.c | 18 +++ builtin/diff.c | 50 ++++--- contrib/completion/git-completion.bash | 15 +- diff-lib.c | 65 ++++++++- diff.h | 6 +- t/t4068-diff-symmetric-merge-base.sh | 193 +++++++++++++++++++++++++ t/t4068-diff-symmetric.sh | 91 ------------ 11 files changed, 358 insertions(+), 143 deletions(-) create mode 100755 t/t4068-diff-symmetric-merge-base.sh delete mode 100755 t/t4068-diff-symmetric.sh Range-diff against v2: 1: 80e9066a59 = 1: 80e9066a59 t4068: remove unnecessary >tmp -: ---------- > 2: 21b20281e6 git-diff-index.txt: make --cached description a proper sentence 2: 8e72bd8fea = 3: ca9568c2ea git-diff.txt: backtick quote command text 3: ea6717e7b3 < -: ---------- builtin/diff: parse --no-index using parse_options() 4: 4f219cf0d1 < -: ---------- builtin/diff: learn --merge-base -: ---------- > 4: 1ac8459541 contrib/completion: extract common diff/difftool options -: ---------- > 5: 496908ac10 diff-lib: accept option flags in run_diff_index() -: ---------- > 6: 6aac57ca02 diff-lib: define diff_get_merge_base() -: ---------- > 7: c9225a0440 t4068: add --merge-base tests -: ---------- > 8: 1e4f805e57 builtin/diff-index: learn --merge-base -: ---------- > 9: c0d27b125e builtin/diff-tree: learn --merge-base -: ---------- > 10: 42a8c9b665 contrib/completion: complete `git diff --merge-base` -- 2.28.0.618.gf4bc123cb7
