Re: [PATCH] log: add %S option (like --source) to log --format

>
> On 12/19/2018 3:33 AM, issac.trotts@gmail.com wrote:
> > From: Issac Trotts <issac.trotts@gmail.com>
> >
> > Make it possible to write for example
> >
> >          git log --format="%H,%S"
> >
> > where the %S at the end is a new placeholder that prints out the ref
> > (tag/branch) for each commit.
> >
> > Using %d might seem like an alternative but it only shows the ref for the last
> > commit in the branch.
> >
> > Signed-off-by: Issac Trotts <issactrotts@google.com>
> >
> > ---
> >
> > This change is based on a question from Stack Overflow:
> > https://stackoverflow.com/questions/12712775/git-get-source-information-in-format
> > ---
> >   Documentation/pretty-formats.txt |  2 ++
> >   builtin/log.c                    |  2 +-
> >   log-tree.c                       |  1 +
> >   pretty.c                         | 15 ++++++++++
> >   pretty.h                         |  1 +
> >   t/t4205-log-pretty-formats.sh    | 50 ++++++++++++++++++++++++++++++++
> >   6 files changed, 70 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
> > index 417b638cd..de6953108 100644
> > --- a/Documentation/pretty-formats.txt
> > +++ b/Documentation/pretty-formats.txt
> > @@ -134,6 +134,8 @@ The placeholders are:
> >   - '%cI': committer date, strict ISO 8601 format
> >   - '%d': ref names, like the --decorate option of linkgit:git-log[1]
> >   - '%D': ref names without the " (", ")" wrapping.
> > +- '%S': ref name given on the command line by which the commit was reached
> > +  (like `git log --source`), only works with `git log`
>
> This "only works with `git log`" made me think about what would happen
> with `git rev-list --pretty=format:"%h %S"` and the answer (on my
> machine) was a segfault.

> >   - '%e': encoding
> >   - '%s': subject
> >   - '%f': sanitized subject line, suitable for a filename
> > diff --git a/builtin/log.c b/builtin/log.c
> > index e8e51068b..be3025657 100644
> > --- a/builtin/log.c
> > +++ b/builtin/log.c
> > @@ -203,7 +203,7 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
> >           rev->diffopt.filter || rev->diffopt.flags.follow_renames)
> >               rev->always_show_header = 0;
> >
> > -     if (source) {
> > +     if (source || (rev->pretty_given && (rev->commit_format == CMIT_FMT_USERFORMAT) && w.source)) {
> >               init_revision_sources(&revision_sources);
> >               rev->sources = &revision_sources;
> >       }
>
> Likely, you'll want to duplicate this initialization in the revision
> machinery. Keep this one in builtin/log.c as it was before, but add
> something like this initialization to setup_revisions(). Add a test for
> rev-list.

>
> [snip]
>
> > @@ -1194,6 +1195,17 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
> >               load_ref_decorations(NULL, DECORATE_SHORT_REFS);
> >               format_decorations_extended(sb, commit, c->auto_color, "", ", ", "");
> >               return 1;
> > +     case 'S':               /* tag/branch like --source */
> > +             if (c->pretty_ctx->rev->sources == NULL) {
> Use "if (!c->pretty_ctx->rev->sources".
> > +                     return 0;
> > +             }
> > +             slot = revision_sources_at(c->pretty_ctx->rev->sources, commit);
> > +             if (slot && *slot) {
> I'm not sure this check for 'slot' being non-null is necessary, as we
> would already get a failure in the commit-slab code (for
> revision_sources_at()) if the slab is not initialized.
> > +                     strbuf_addstr(sb, *slot);
> > +                     return 1;
> > +             } else {
> > +                     die(_("failed to get info for %%S"));
>
> Here, you die() when you fail to get a slot but above you return 0 when
> the sources are not initialized.
>
> I don't see another use of die() in this method. Is that the right way
> to handle failure here? (I'm legitimately asking because I have
> over-used 'die()' in the past and am still unclear on when it is
> appropriate.)

>
> >   '
> >
> > +test_expect_success 'set up %S tests' '
> > +     git checkout --orphan source-a &&
> > +     test_commit one &&
> > +     test_commit two &&
> > +     git checkout -b source-b HEAD^ &&
> > +     test_commit three
> > +'
> > +
> > +test_expect_success 'log --format=%S paints branch names' '
> > +     cat >expect <<-\EOF &&
> > +     source-b
> > +     source-a
> > +     source-b
> > +     EOF
> > +     git log --format=%S source-a source-b >actual &&
> > +     test_cmp expect actual
> > +'
> > +
> > +test_expect_success 'log --format=%S paints tag names' '
> > +     git tag -m tagged source-tag &&
> > +     cat >expect <<-\EOF &&
> > +     source-tag
> > +     source-a
> > +     source-tag
> > +     EOF
> > +     git log --format=%S source-tag source-a >actual &&
> > +     test_cmp expect actual
> > +'
> > +
> > +test_expect_success 'log --format=%S paints symmetric ranges' '
> > +     cat >expect <<-\EOF &&
> > +     source-b
> > +     source-a
> > +     EOF
> > +     git log --format=%S source-a...source-b >actual &&
> > +     test_cmp expect actual
> > +'
> > +
> > +test_expect_success '%S in git log --format works with other placeholders (part 1)' '
> > +     git log --format="source-b %h" source-b >expect &&
> > +     git log --format="%S %h" source-b >actual &&
> > +     test_cmp expect actual
> > +'
> > +
> > +test_expect_success '%S in git log --format works with other placeholders (part 2)' '
> > +     git log --format="%h source-b" source-b >expect &&
> > +     git log --format="%h %S" source-b >actual &&
> > +     test_cmp expect actual
> > +'
> > +
> >   test_done
>
> Please also add a simple test to t6006-rev-list-format.sh.

>
> Thanks,
>
> -Stolee
>