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




On 12/19/2018 3:33 AM, issac.trotts@xxxxxxxxx wrote:
From: Issac Trotts <issac.trotts@xxxxxxxxx>

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@xxxxxxxxxx>

---

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