Merge branch 'sg/name-rev-wo-recursion'

Redo "git name-rev" to avoid recursive calls.

* sg/name-rev-wo-recursion:
  name-rev: cleanup name_ref()
  name-rev: eliminate recursion in name_rev()
  name-rev: use 'name->tip_name' instead of 'tip_name'
  name-rev: drop name_rev()'s 'generation' and 'distance' parameters
  name-rev: restructure creating/updating 'struct rev_name' instances
  name-rev: restructure parsing commits and applying date cutoff
  name-rev: pull out deref handling from the recursion
  name-rev: extract creating/updating a 'struct name_rev' into a helper
  t6120: add a test to cover inner conditions in 'git name-rev's name_rev()
  name-rev: use sizeof(*ptr) instead of sizeof(type) in allocation
  name-rev: avoid unnecessary cast in name_ref()
  name-rev: use strbuf_strip_suffix() in get_rev_name()
  t6120-describe: modernize the 'check_describe' helper
  t6120-describe: correct test repo history graph in comment

t/t6120-describe.sh

@@ -1,28 +1,27 @@
 #!/bin/sh
 
-test_description='test describe
+test_description='test describe'
+
+#  o---o-----o----o----o-------o----x
+#       \   D,R   e           /
+#        \---o-------------o-'
+#         \  B            /
+#          `-o----o----o-'
+#                 A    c
+#
+# First parent of a merge commit is on the same line, second parent below.
 
-                       B
-        .--------------o----o----o----x
-       /                   /    /
- o----o----o----o----o----.    /
-       \        A    c        /
-        .------------o---o---o
-                   D,R   e
-'
 . ./test-lib.sh
 
 check_describe () {
 	expect="$1"
 	shift
-	R=$(git describe "$@" 2>err.actual)
-	S=$?
-	cat err.actual >&3
-	test_expect_success "describe $*" '
-	test $S = 0 &&
+	describe_opts="$@"
+	test_expect_success "describe $describe_opts" '
+	R=$(git describe $describe_opts 2>err.actual) &&
 	case "$R" in
 	$expect)	echo happy ;;
-	*)	echo "Oops - $R is not $expect";
+	*)	echo "Oops - $R is not $expect" &&
 		false ;;
 	esac
 	'
@@ -382,7 +381,7 @@ test_expect_success 'describe tag object' '
 	test_i18ngrep "fatal: test-blob-1 is neither a commit nor blob" actual
 '
 
-test_expect_failure ULIMIT_STACK_SIZE 'name-rev works in a deep repo' '
+test_expect_success ULIMIT_STACK_SIZE 'name-rev works in a deep repo' '
 	i=1 &&
 	while test $i -lt 8000
 	do
@@ -439,4 +438,45 @@ test_expect_success 'name-rev a rev shortly after epoch' '
 	test_cmp expect actual
 '
 
+# A--------------master
+#  \            /
+#   \----------M2
+#    \        /
+#     \---M1-C
+#      \ /
+#       B
+test_expect_success 'name-rev covers all conditions while looking at parents' '
+	git init repo &&
+	(
+		cd repo &&
+
+		echo A >file &&
+		git add file &&
+		git commit -m A &&
+		A=$(git rev-parse HEAD) &&
+
+		git checkout --detach &&
+		echo B >file &&
+		git commit -m B file &&
+		B=$(git rev-parse HEAD) &&
+
+		git checkout $A &&
+		git merge --no-ff $B &&  # M1
+
+		echo C >file &&
+		git commit -m C file &&
+
+		git checkout $A &&
+		git merge --no-ff HEAD@{1} && # M2
+
+		git checkout master &&
+		git merge --no-ff HEAD@{1} &&
+
+		echo "$B master^2^2~1^2" >expect &&
+		git name-rev $B >actual &&
+
+		test_cmp expect actual
+	)
+'
+
 test_done