[PATCHv3 0/7] git describe blob

[Stefan Beller <sbeller@google.com>]

Thanks for the discussion on v2[1].

Interdiff is below, just fixing minor things.

We'll keep the original algorithm for now, deferring an improvement on 
the algorithm front towards a future developer.

Thanks,
Stefan

[1] https://public-inbox.org/git/20171031211852.13001-1-sbeller@google.com/

Stefan Beller (7):
  t6120: fix typo in test name
  list-objects.c: factor out traverse_trees_and_blobs
  revision.h: introduce blob/tree walking in order of the commits
  builtin/describe.c: rename `oid` to avoid variable shadowing
  builtin/describe.c: print debug statements earlier
  builtin/describe.c: factor out describe_commit
  builtin/describe.c: describe a blob

 Documentation/git-describe.txt     |  13 +++-
 Documentation/rev-list-options.txt |   5 ++
 builtin/describe.c                 | 125 ++++++++++++++++++++++++++++---------
 list-objects.c                     |  52 +++++++++------
 revision.c                         |   2 +
 revision.h                         |   3 +-
 t/t6100-rev-list-in-order.sh       |  47 ++++++++++++++
 t/t6120-describe.sh                |  17 ++++-
 8 files changed, 214 insertions(+), 50 deletions(-)
 create mode 100755 t/t6100-rev-list-in-order.sh
diff --git c/Documentation/git-describe.txt w/Documentation/git-describe.txt
index 077c3c2193..79ec0be62a 100644
--- c/Documentation/git-describe.txt
+++ w/Documentation/git-describe.txt
@@ -11,7 +11,7 @@ SYNOPSIS
 [verse]
 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] [<commit-ish>...]
 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>]
-'git describe' [<options>] <blob-ish>
+'git describe' [<options>] <blob>
 
 DESCRIPTION
 -----------
diff --git c/builtin/describe.c w/builtin/describe.c
index 382cbae908..cf08bef344 100644
--- c/builtin/describe.c
+++ w/builtin/describe.c
@@ -440,6 +440,7 @@ struct process_commit_data {
 	struct object_id current_commit;
 	struct object_id looking_for;
 	struct strbuf *dst;
+	struct rev_info *revs;
 };
 
 static void process_commit(struct commit *commit, void *data)
@@ -456,6 +457,7 @@ static void process_object(struct object *obj, const char *path, void *data)
 		reset_revision_walk();
 		describe_commit(&pcd->current_commit, pcd->dst);
 		strbuf_addf(pcd->dst, ":%s", path);
+		pcd->revs->max_count = 0;
 	}
 }
 
@@ -463,7 +465,7 @@ static void describe_blob(struct object_id oid, struct strbuf *dst)
 {
 	struct rev_info revs;
 	struct argv_array args = ARGV_ARRAY_INIT;
-	struct process_commit_data pcd = { null_oid, oid, dst};
+	struct process_commit_data pcd = { null_oid, oid, dst, &revs};
 
 	argv_array_pushl(&args, "internal: The first arg is not parsed",
 		"--all", "--reflog", /* as many starting points as possible */
@@ -497,14 +499,12 @@ static void describe(const char *arg, int last_one)
 		die(_("Not a valid object name %s"), arg);
 	cmit = lookup_commit_reference_gently(&oid, 1);
 
-	if (cmit) {
+	if (cmit)
 		describe_commit(&oid, &sb);
-	} else {
-		if (lookup_blob(&oid))
-			describe_blob(oid, &sb);
-		else
-			die(_("%s is neither a commit nor blob"), arg);
-	}
+	else if (lookup_blob(&oid))
+		describe_blob(oid, &sb);
+	else
+		die(_("%s is neither a commit nor blob"), arg);
 
 	puts(sb.buf);
 
diff --git c/list-objects.c w/list-objects.c
index 03438e5a8b..07a92f35fe 100644
--- c/list-objects.c
+++ w/list-objects.c
@@ -184,13 +184,13 @@ static void add_pending_tree(struct rev_info *revs, struct tree *tree)
 }
 
 static void traverse_trees_and_blobs(struct rev_info *revs,
-				     struct strbuf *base_path,
+				     struct strbuf *base,
 				     show_object_fn show_object,
 				     void *data)
 {
 	int i;
 
-	assert(base_path->len == 0);
+	assert(base->len == 0);
 
 	for (i = 0; i < revs->pending.nr; i++) {
 		struct object_array_entry *pending = revs->pending.objects + i;
@@ -208,12 +208,12 @@ static void traverse_trees_and_blobs(struct rev_info *revs,
 			path = "";
 		if (obj->type == OBJ_TREE) {
 			process_tree(revs, (struct tree *)obj, show_object,
-				     base_path, path, data);
+				     base, path, data);
 			continue;
 		}
 		if (obj->type == OBJ_BLOB) {
 			process_blob(revs, (struct blob *)obj, show_object,
-				     base_path, path, data);
+				     base, path, data);
 			continue;
 		}
 		die("unknown pending object %s (%s)",
diff --git c/t/t6100-rev-list-in-order.sh w/t/t6100-rev-list-in-order.sh
index 651666979b..d4d539b0da 100755
--- c/t/t6100-rev-list-in-order.sh
+++ w/t/t6100-rev-list-in-order.sh
@@ -1,21 +1,22 @@
 #!/bin/sh
 
-test_description='miscellaneous rev-list tests'
+test_description='rev-list testing in-commit-order'
 
 . ./test-lib.sh
 
-
-test_expect_success 'setup' '
+test_expect_success 'rev-list --in-commit-order' '
 	for x in one two three four
 	do
 		echo $x >$x &&
 		git add $x &&
-		git commit -m "add file $x"
+		git commit -m "add file $x" ||
+		return 1
 	done &&
 	for x in four three
 	do
 		git rm $x &&
-		git commit -m "remove $x"
+		git commit -m "remove $x" ||
+		return 1
 	done &&
 	git rev-list --in-commit-order --objects HEAD >actual.raw &&
 	cut -c 1-40 >actual <actual.raw &&
@@ -32,9 +33,9 @@ test_expect_success 'setup' '
 		HEAD~2^{tree}
 		HEAD~2^{tree}:four
 		HEAD~3^{commit}
-		# HEAD~3^{tree} skipped
+		# HEAD~3^{tree} skipped, same as HEAD~1^{tree}
 		HEAD~4^{commit}
-		# HEAD~4^{tree} skipped
+		# HEAD~4^{tree} skipped, same as HEAD^{tree}
 		HEAD~5^{commit}
 		HEAD~5^{tree}
 	EOF
diff --git c/t/t6120-describe.sh w/t/t6120-describe.sh
index fd329f173a..aec6ed192d 100755
--- c/t/t6120-describe.sh
+++ w/t/t6120-describe.sh
@@ -319,7 +319,7 @@ test_expect_success 'describe a blob at a tag' '
 	test_cmp expect actual
 '
 
-test_expect_success 'describe a surviving blob' '
+test_expect_success 'describe a blob with commit-ish' '
 	git commit --allow-empty -m "empty commit" &&
 	git describe HEAD:file >actual &&
 	grep unique-file-1-g actual