# [PATCH] diff: resurrect XDF_NEED_MINIMAL with --minimal 3 messages from 2011-10-02 to 2011-10-03. Participants: Junio C Hamano, Jonathan Nieder, Tay Ray Chuan. Thread: https://gitlist.dev/t/28550 ## Junio C Hamano, 2011-10-02 05:04 Subject: [PATCH] diff: resurrect XDF_NEED_MINIMAL with --minimal Message-ID: <7voby0j86c.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7voby0j86c.fsf%40alter.siamese.dyndns.org ``` Earlier, 582aa00 (git diff too slow for a file, 2010-05-02) unconditionally dropped XDF_NEED_MINIMAL option from the internal xdiff invocation to help performance on pathological cases, while hinting that a follow-up patch could reintroduce it with "--minimal" option from the command line. Make it so. Signed-off-by: Junio C Hamano --- * This together with René's c5aa906 (Revert removal of multi-match discard heuristic in 27af01, 2011-09-25) on top of v1.7.7 seems to give identical diff output as v1.7.1 (e.g. "git diff-tree -p v2.6.39 v3.0" in the kernel repository, with "--minimal"). diff.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/diff.c b/diff.c index 93ef9a2..34a88db 100644 --- a/diff.c +++ b/diff.c @@ -3511,6 +3511,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac) } else if (!strcmp(arg, "--abbrev")) options->abbrev = DEFAULT_ABBREV; + else if (!strcmp(arg, "--minimal")) + DIFF_XDL_SET(options, NEED_MINIMAL); + else if (!strcmp(arg, "--no-minimal")) + DIFF_XDL_CLR(options, NEED_MINIMAL); else if (!prefixcmp(arg, "--abbrev=")) { options->abbrev = strtoul(arg + 9, NULL, 10); if (options->abbrev < MINIMUM_ABBREV) -- 1.7.7 ``` ## Jonathan Nieder, 2011-10-03 12:38 Subject: Re: [PATCH] diff: resurrect XDF_NEED_MINIMAL with --minimal Message-ID: <20111003123843.GA15493@elie> URL: https://gitlist.dev/e/20111003123843.GA15493%40elie In-Reply-To: <7voby0j86c.fsf@alter.siamese.dyndns.org> ``` Junio C Hamano wrote: > * This together with René's c5aa906 (Revert removal of multi-match > discard heuristic in 27af01, 2011-09-25) on top of v1.7.7 seems to give > identical diff output as v1.7.1 (e.g. "git diff-tree -p v2.6.39 v3.0" > in the kernel repository, with "--minimal"). Very neat. > --- a/diff.c > +++ b/diff.c > @@ -3511,6 +3511,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac) > } > else if (!strcmp(arg, "--abbrev")) > options->abbrev = DEFAULT_ABBREV; > + else if (!strcmp(arg, "--minimal")) > + DIFF_XDL_SET(options, NEED_MINIMAL); > + else if (!strcmp(arg, "--no-minimal")) > + DIFF_XDL_CLR(options, NEED_MINIMAL); > else if (!prefixcmp(arg, "--abbrev=")) { I think this would fit well near --patience (the "xdiff options" section), instead of hidden between the unsticked and sticked forms of --abbrev. ;-) Like this: diff --git i/Documentation/diff-options.txt w/Documentation/diff-options.txt index b620b3af..4d87256e 100644 --- i/Documentation/diff-options.txt +++ w/Documentation/diff-options.txt @@ -48,6 +48,10 @@ endif::git-format-patch[] --patience:: Generate a diff using the "patience diff" algorithm. +--minimal:: + Spend extra time to make sure the smallest possible + diff is produced. + --stat[=[,[,]]]:: Generate a diffstat. You can override the default output width for 80-column terminal by `--stat=`. diff --git i/diff.c w/diff.c index fcc00780..2282f86f 100644 --- i/diff.c +++ w/diff.c @@ -3393,6 +3393,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac) DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL); else if (!strcmp(arg, "--patience")) DIFF_XDL_SET(options, PATIENCE_DIFF); + else if (!strcmp(arg, "--minimal")) + DIFF_XDL_SET(options, NEED_MINIMAL); + else if (!strcmp(arg, "--no-minimal")) + DIFF_XDL_CLR(options, NEED_MINIMAL); else if (!strcmp(arg, "--histogram")) DIFF_XDL_SET(options, HISTOGRAM_DIFF); ``` ## Tay Ray Chuan, 2011-10-03 13:04 Subject: Re: [PATCH] diff: resurrect XDF_NEED_MINIMAL with --minimal Message-ID: URL: https://gitlist.dev/e/CALUzUxrfUF5sbgSv3dwkBC6cggV3mqRDDMrpP-zX_86xdt6ZYA%40mail.gmail.com In-Reply-To: <20111003123843.GA15493@elie> ``` On Mon, Oct 3, 2011 at 8:38 PM, Jonathan Nieder wrote: Thanks for the Cc, Johnathan. > Junio C Hamano wrote: > >>  * This together with René's c5aa906 (Revert removal of multi-match >>    discard heuristic in 27af01, 2011-09-25) on top of v1.7.7 seems to give >>    identical diff output as v1.7.1 (e.g. "git diff-tree -p v2.6.39 v3.0" >>    in the kernel repository, with "--minimal"). > > Very neat. Interesting. Clearly there is more than just the multi-match discard heuristic in (xdl_clean_mmatch() and xdl_cleanup_records()). > diff --git i/diff.c w/diff.c > index fcc00780..2282f86f 100644 > --- i/diff.c > +++ w/diff.c > @@ -3393,6 +3393,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac) >                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL); >        else if (!strcmp(arg, "--patience")) >                DIFF_XDL_SET(options, PATIENCE_DIFF); > +       else if (!strcmp(arg, "--minimal")) > +               DIFF_XDL_SET(options, NEED_MINIMAL); > +       else if (!strcmp(arg, "--no-minimal")) > +               DIFF_XDL_CLR(options, NEED_MINIMAL); >        else if (!strcmp(arg, "--histogram")) >                DIFF_XDL_SET(options, HISTOGRAM_DIFF); > > That's an improvement, but it would be even better if it was placed above the -- options, instead of being placed between them. -- Cheers, Ray Chuan ```