Show the root commit in a followed log

A followed log diffs each commit against its parent to learn whether
the file changed there, and a root commit was skipped rather than
diffed against the empty tree, so a file created in the first commit
never showed that commit.

2 files changed, 50 insertions, 13 deletions

diff --git a/source/ui-log.c b/source/ui-log.cindex f96689e..8adc5ac 100644--- a/source/ui-log.c+++ b/source/ui-log.c@@ -88,15 +88,16 @@ static void follow_path(struct diff_filepair *pair)  /*  * Whether a commit belongs in the listing. When a single path is being- * followed the commit is diffed against its one parent here, and the counts- * that fall out of that diff are kept so the row does not repeat the work.+ * followed the commit is diffed against its one parent here, or against the+ * empty tree when it is the root, and the counts that fall out of that diff+ * are kept so the row does not repeat the work.  */ static int should_show(struct commit *commit, struct rev_info *revs) { 	// Static, because the walk keeps the address in its diff options. 	static filepair_fn follow = follow_path; 	struct commit_list *parents = commit->parents;-	struct commit *parent;+	const struct object_id *parent_tree = NULL; 	int found = 0, saved_fmt; 	struct diff_flags saved_flags = revs->diffopt.flags; @@ -108,22 +109,20 @@ static int should_show(struct commit *commit, struct rev_info *revs) 	if (parents && parents->next) 		return 0; -	if (!parents)-		return revs->show_root_diff;--	parent = parents->item;--	// A parent that does not parse is left for print_commit to report on,-	// so the commit is shown.-	if (repo_parse_commit(the_repository, parent))-		return 1;+	if (parents) {+		// A parent that does not parse is left for print_commit to+		// report on, so the commit is shown.+		if (repo_parse_commit(the_repository, parents->item))+			return 1;+		parent_tree = get_commit_tree_oid(parents->item);+	}  	file_count = 0; 	added_lines = 0; 	removed_lines = 0;  	revs->diffopt.flags.recursive = 1;-	diff_tree_oid(get_commit_tree_oid(parent), get_commit_tree_oid(commit), "", &revs->diffopt);+	diff_tree_oid(parent_tree, get_commit_tree_oid(commit), "", &revs->diffopt); 	diffcore_std(&revs->diffopt);  	found = !diff_queue_is_empty(&revs->diffopt);
diff --git a/source/ui-log.c b/source/ui-log.c
index f96689e..8adc5ac 100644
--- a/source/ui-log.c
+++ b/source/ui-log.c
@@ -88,15 +88,16 @@ static void follow_path(struct diff_filepair *pair)
 
 /*
  * Whether a commit belongs in the listing. When a single path is being
- * followed the commit is diffed against its one parent here, and the counts
- * that fall out of that diff are kept so the row does not repeat the work.
+ * followed the commit is diffed against its one parent here, or against the
+ * empty tree when it is the root, and the counts that fall out of that diff
+ * are kept so the row does not repeat the work.
  */
 static int should_show(struct commit *commit, struct rev_info *revs)
 {
 	// Static, because the walk keeps the address in its diff options.
 	static filepair_fn follow = follow_path;
 	struct commit_list *parents = commit->parents;
-	struct commit *parent;
+	const struct object_id *parent_tree = NULL;
 	int found = 0, saved_fmt;
 	struct diff_flags saved_flags = revs->diffopt.flags;
 
@@ -108,22 +109,20 @@ static int should_show(struct commit *commit, struct rev_info *revs)
 	if (parents && parents->next)
 		return 0;
 
-	if (!parents)
-		return revs->show_root_diff;
-
-	parent = parents->item;
-
-	// A parent that does not parse is left for print_commit to report on,
-	// so the commit is shown.
-	if (repo_parse_commit(the_repository, parent))
-		return 1;
+	if (parents) {
+		// A parent that does not parse is left for print_commit to
+		// report on, so the commit is shown.
+		if (repo_parse_commit(the_repository, parents->item))
+			return 1;
+		parent_tree = get_commit_tree_oid(parents->item);
+	}
 
 	file_count = 0;
 	added_lines = 0;
 	removed_lines = 0;
 
 	revs->diffopt.flags.recursive = 1;
-	diff_tree_oid(get_commit_tree_oid(parent), get_commit_tree_oid(commit), "", &revs->diffopt);
+	diff_tree_oid(parent_tree, get_commit_tree_oid(commit), "", &revs->diffopt);
 	diffcore_std(&revs->diffopt);
 
 	found = !diff_queue_is_empty(&revs->diffopt);
diff --git a/tests/t0103-log.sh b/tests/t0103-log.shindex 16fabda..08f9ddd 100755--- a/tests/t0103-log.sh+++ b/tests/t0103-log.sh@@ -45,4 +45,42 @@ test_expect_success 'no links with space in path' '! grep "href=./with space/" t test_expect_success 'no links with space in arg' '! grep "q=commit 1" tmp' test_expect_success 'commit 2 is not visible' '! grep "commit 2" tmp' +# Following a file diffs each commit for the name the file had there, so the+# root commit that created it has to be diffed too.+test_expect_success 'set up a renamed file to follow' '+	test_create_repo repos/fol &&+	(+		cd repos/fol &&+		echo 1 >a.txt &&+		git add a.txt &&+		git commit -m "create a" &&+		for i in 2 3 4+		do+			echo $i >>a.txt &&+			git commit -am "edit a $i" || return 1+		done &&+		git mv a.txt b.txt &&+		git commit -m "rename to b" &&+		for i in 6 7 8+		do+			echo $i >>b.txt &&+			git commit -am "edit b $i" || return 1+		done+	) &&+	{+		echo "virtual-root=/" &&+		echo "cache-size=0" &&+		echo "enable-follow-links=1" &&+		echo "max-commit-count=3" &&+		echo "repo.url=fol" &&+		echo "repo.path=$PWD/repos/fol/.git"+	} >folrc+'++test_expect_success 'a followed log reaches the root commit' '+	CGIT_CONFIG="$PWD/folrc" QUERY_STRING="url=fol/log/b.txt&follow=1&ofs=6" cgit >tmp &&+	grep ">edit a 2<" tmp &&+	grep ">create a<" tmp+'+ test_done
diff --git a/tests/t0103-log.sh b/tests/t0103-log.sh
index 16fabda..08f9ddd 100755
--- a/tests/t0103-log.sh
+++ b/tests/t0103-log.sh
@@ -45,4 +45,42 @@ test_expect_success 'no links with space in path' '! grep "href=./with space/" t
 test_expect_success 'no links with space in arg' '! grep "q=commit 1" tmp'
 test_expect_success 'commit 2 is not visible' '! grep "commit 2" tmp'
 
+# Following a file diffs each commit for the name the file had there, so the
+# root commit that created it has to be diffed too.
+test_expect_success 'set up a renamed file to follow' '
+	test_create_repo repos/fol &&
+	(
+		cd repos/fol &&
+		echo 1 >a.txt &&
+		git add a.txt &&
+		git commit -m "create a" &&
+		for i in 2 3 4
+		do
+			echo $i >>a.txt &&
+			git commit -am "edit a $i" || return 1
+		done &&
+		git mv a.txt b.txt &&
+		git commit -m "rename to b" &&
+		for i in 6 7 8
+		do
+			echo $i >>b.txt &&
+			git commit -am "edit b $i" || return 1
+		done
+	) &&
+	{
+		echo "virtual-root=/" &&
+		echo "cache-size=0" &&
+		echo "enable-follow-links=1" &&
+		echo "max-commit-count=3" &&
+		echo "repo.url=fol" &&
+		echo "repo.path=$PWD/repos/fol/.git"
+	} >folrc
+'
+
+test_expect_success 'a followed log reaches the root commit' '
+	CGIT_CONFIG="$PWD/folrc" QUERY_STRING="url=fol/log/b.txt&follow=1&ofs=6" cgit >tmp &&
+	grep ">edit a 2<" tmp &&
+	grep ">create a<" tmp
+'
+
 test_done