Merge branch 'jc/topo-author-date-sort'

"git log" learned the "--author-date-order" option, with which the
output is topologically sorted and commits in parallel histories
are shown intermixed together based on the author timestamp.

* jc/topo-author-date-sort:
  t6003: add --author-date-order test
  topology tests: teach a helper to set author dates as well
  t6003: add --date-order test
  topology tests: teach a helper to take abbreviated timestamps
  t/lib-t6000: style fixes
  log: --author-date-order
  sort-in-topological-order: use prio-queue
  prio-queue: priority queue of pointers to structs
  toposort: rename "lifo" field

4 files changed, 219 insertions, 120 deletions

diff --git a/t/lib-t6000.sh b/t/lib-t6000.sh
index ea25dd8..4ffd901 100644
--- a/t/lib-t6000.sh
+++ b/t/lib-t6000.sh
@@ -1,55 +1,50 @@
 : included from 6002 and others
 
-[ -d .git/refs/tags ] || mkdir -p .git/refs/tags
+mkdir -p .git/refs/tags
 
-:> sed.script
+>sed.script
 
-# Answer the sha1 has associated with the tag. The tag must exist in .git or .git/refs/tags
-tag()
-{
+# Answer the sha1 has associated with the tag. The tag must exist in .git/refs/tags
+tag () {
 	_tag=$1
-	[ -f .git/refs/tags/$_tag ] || error "tag: \"$_tag\" does not exist"
-	cat .git/refs/tags/$_tag
+	test -f ".git/refs/tags/$_tag" || error "tag: \"$_tag\" does not exist"
+	cat ".git/refs/tags/$_tag"
 }
 
 # Generate a commit using the text specified to make it unique and the tree
 # named by the tag specified.
-unique_commit()
-{
+unique_commit () {
 	_text=$1
-        _tree=$2
+	_tree=$2
 	shift 2
-	echo $_text | git commit-tree $(tag $_tree) "$@"
+	echo "$_text" | git commit-tree $(tag "$_tree") "$@"
 }
 
 # Save the output of a command into the tag specified. Prepend
 # a substitution script for the tag onto the front of sed.script
-save_tag()
-{
+save_tag () {
 	_tag=$1
-	[ -n "$_tag" ] || error "usage: save_tag tag commit-args ..."
+	test -n "$_tag" || error "usage: save_tag tag commit-args ..."
 	shift 1
-	"$@" >.git/refs/tags/$_tag
+	"$@" >".git/refs/tags/$_tag"
 
-        echo "s/$(tag $_tag)/$_tag/g" > sed.script.tmp
-	cat sed.script >> sed.script.tmp
+	echo "s/$(tag $_tag)/$_tag/g" >sed.script.tmp
+	cat sed.script >>sed.script.tmp
 	rm sed.script
 	mv sed.script.tmp sed.script
 }
 
 # Replace unhelpful sha1 hashses with their symbolic equivalents
-entag()
-{
+entag () {
 	sed -f sed.script
 }
 
 # Execute a command after first saving, then setting the GIT_AUTHOR_EMAIL
 # tag to a specified value. Restore the original value on return.
-as_author()
-{
+as_author () {
 	_author=$1
 	shift 1
-        _save=$GIT_AUTHOR_EMAIL
+	_save=$GIT_AUTHOR_EMAIL
 
 	GIT_AUTHOR_EMAIL="$_author"
 	export GIT_AUTHOR_EMAIL
@@ -63,45 +58,58 @@ as_author()
 	fi
 }
 
-commit_date()
-{
-        _commit=$1
-	git cat-file commit $_commit | sed -n "s/^committer .*> \([0-9]*\) .*/\1/p"
+commit_date () {
+	_commit=$1
+	git cat-file commit $_commit |
+	sed -n "s/^committer .*> \([0-9]*\) .*/\1/p"
 }
 
-on_committer_date()
-{
-    _date=$1
-    shift 1
-    GIT_COMMITTER_DATE="$_date"
-    export GIT_COMMITTER_DATE
-    "$@"
-    unset GIT_COMMITTER_DATE
+# Assign the value of fake date to a variable, but
+# allow fairly common "1971-08-16 00:00" to be omittd
+assign_fake_date () {
+	case "$2" in
+	??:??:??)	eval "$1='1971-08-16 $2'" ;;
+	??:??)		eval "$1='1971-08-16 00:$2'" ;;
+	??)		eval "$1='1971-08-16 00:00:$2'" ;;
+	*)		eval "$1='$2'" ;;
+	esac
+}
+
+on_committer_date () {
+	assign_fake_date GIT_COMMITTER_DATE "$1"
+	export GIT_COMMITTER_DATE
+	shift 1
+	"$@"
+}
+
+on_dates () {
+	assign_fake_date GIT_COMMITTER_DATE "$1"
+	assign_fake_date GIT_AUTHOR_DATE "$2"
+	export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
+	shift 2
+	"$@"
 }
 
 # Execute a command and suppress any error output.
-hide_error()
-{
+hide_error () {
 	"$@" 2>/dev/null
 }
 
-check_output()
-{
+check_output () {
 	_name=$1
 	shift 1
-	if eval "$*" | entag > $_name.actual
+	if eval "$*" | entag >"$_name.actual"
 	then
-		test_cmp $_name.expected $_name.actual
+		test_cmp "$_name.expected" "$_name.actual"
 	else
-		return 1;
+		return 1
 	fi
 }
 
 # Turn a reasonable test description into a reasonable test name.
 # All alphanums translated into -'s which are then compressed and stripped
 # from front and back.
-name_from_description()
-{
+name_from_description () {
 	perl -pe '
 		s/[^A-Za-z0-9.]/-/g;
 		s/-+/-/g;
@@ -119,9 +127,11 @@ name_from_description()
 test_output_expect_success()
 {
 	_description=$1
-        _test=$2
-        [ $# -eq 2 ] || error "usage: test_output_expect_success description test <<EOF ... EOF"
-        _name=$(echo $_description | name_from_description)
-	cat > $_name.expected
+	_test=$2
+	test $# -eq 2 ||
+	error "usage: test_output_expect_success description test <<EOF ... EOF"
+
+	_name=$(echo $_description | name_from_description)
+	cat >"$_name.expected"
 	test_expect_success "$_description" "check_output $_name \"$_test\""
 }
diff --git a/t/t0009-prio-queue.sh b/t/t0009-prio-queue.sh
new file mode 100755
index 0000000..94045c3
--- /dev/null
+++ b/t/t0009-prio-queue.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+test_description='basic tests for priority queue implementation'
+. ./test-lib.sh
+
+cat >expect <<'EOF'
+1
+2
+3
+4
+5
+5
+6
+7
+8
+9
+10
+EOF
+test_expect_success 'basic ordering' '
+	test-prio-queue 2 6 3 10 9 5 7 4 5 8 1 dump >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+2
+3
+4
+1
+5
+6
+EOF
+test_expect_success 'mixed put and get' '
+	test-prio-queue 6 2 4 get 5 3 get get 1 dump >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+1
+2
+NULL
+1
+2
+NULL
+EOF
+test_expect_success 'notice empty queue' '
+	test-prio-queue 1 2 get get get 1 2 get get get >actual &&
+	test_cmp expect actual
+'
+
+test_done
diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index fb07536..43ad772 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh
@@ -39,25 +39,25 @@ test_bisection_diff()
 date >path0
 git update-index --add path0
 save_tag tree git write-tree
-on_committer_date "1971-08-16 00:00:00" hide_error save_tag root unique_commit root tree
-on_committer_date "1971-08-16 00:00:01" save_tag l0 unique_commit l0 tree -p root
-on_committer_date "1971-08-16 00:00:02" save_tag l1 unique_commit l1 tree -p l0
-on_committer_date "1971-08-16 00:00:03" save_tag l2 unique_commit l2 tree -p l1
-on_committer_date "1971-08-16 00:00:04" save_tag a0 unique_commit a0 tree -p l2
-on_committer_date "1971-08-16 00:00:05" save_tag a1 unique_commit a1 tree -p a0
-on_committer_date "1971-08-16 00:00:06" save_tag b1 unique_commit b1 tree -p a0
-on_committer_date "1971-08-16 00:00:07" save_tag c1 unique_commit c1 tree -p b1
-on_committer_date "1971-08-16 00:00:08" save_tag b2 unique_commit b2 tree -p b1
-on_committer_date "1971-08-16 00:00:09" save_tag b3 unique_commit b2 tree -p b2
-on_committer_date "1971-08-16 00:00:10" save_tag c2 unique_commit c2 tree -p c1 -p b2
-on_committer_date "1971-08-16 00:00:11" save_tag c3 unique_commit c3 tree -p c2
-on_committer_date "1971-08-16 00:00:12" save_tag a2 unique_commit a2 tree -p a1
-on_committer_date "1971-08-16 00:00:13" save_tag a3 unique_commit a3 tree -p a2
-on_committer_date "1971-08-16 00:00:14" save_tag b4 unique_commit b4 tree -p b3 -p a3
-on_committer_date "1971-08-16 00:00:15" save_tag a4 unique_commit a4 tree -p a3 -p b4 -p c3
-on_committer_date "1971-08-16 00:00:16" save_tag l3 unique_commit l3 tree -p a4
-on_committer_date "1971-08-16 00:00:17" save_tag l4 unique_commit l4 tree -p l3
-on_committer_date "1971-08-16 00:00:18" save_tag l5 unique_commit l5 tree -p l4
+on_committer_date "00:00" hide_error save_tag root unique_commit root tree
+on_committer_date "00:01" save_tag l0 unique_commit l0 tree -p root
+on_committer_date "00:02" save_tag l1 unique_commit l1 tree -p l0
+on_committer_date "00:03" save_tag l2 unique_commit l2 tree -p l1
+on_committer_date "00:04" save_tag a0 unique_commit a0 tree -p l2
+on_committer_date "00:05" save_tag a1 unique_commit a1 tree -p a0
+on_committer_date "00:06" save_tag b1 unique_commit b1 tree -p a0
+on_committer_date "00:07" save_tag c1 unique_commit c1 tree -p b1
+on_committer_date "00:08" save_tag b2 unique_commit b2 tree -p b1
+on_committer_date "00:09" save_tag b3 unique_commit b2 tree -p b2
+on_committer_date "00:10" save_tag c2 unique_commit c2 tree -p c1 -p b2
+on_committer_date "00:11" save_tag c3 unique_commit c3 tree -p c2
+on_committer_date "00:12" save_tag a2 unique_commit a2 tree -p a1
+on_committer_date "00:13" save_tag a3 unique_commit a3 tree -p a2
+on_committer_date "00:14" save_tag b4 unique_commit b4 tree -p b3 -p a3
+on_committer_date "00:15" save_tag a4 unique_commit a4 tree -p a3 -p b4 -p c3
+on_committer_date "00:16" save_tag l3 unique_commit l3 tree -p a4
+on_committer_date "00:17" save_tag l4 unique_commit l4 tree -p l3
+on_committer_date "00:18" save_tag l5 unique_commit l5 tree -p l4
 git update-ref HEAD $(tag l5)
 
 
@@ -90,29 +90,29 @@ git update-ref HEAD $(tag l5)
 #     F
 
 
-on_committer_date "1971-08-16 00:00:00" hide_error save_tag F unique_commit F tree
-on_committer_date "1971-08-16 00:00:01" save_tag e8 unique_commit e8 tree -p F
-on_committer_date "1971-08-16 00:00:02" save_tag e7 unique_commit e7 tree -p e8
-on_committer_date "1971-08-16 00:00:03" save_tag e6 unique_commit e6 tree -p e7
-on_committer_date "1971-08-16 00:00:04" save_tag e5 unique_commit e5 tree -p e6
-on_committer_date "1971-08-16 00:00:05" save_tag f4 unique_commit f4 tree -p F
-on_committer_date "1971-08-16 00:00:06" save_tag f3 unique_commit f3 tree -p f4
-on_committer_date "1971-08-16 00:00:07" save_tag f2 unique_commit f2 tree -p f3
-on_committer_date "1971-08-16 00:00:08" save_tag f1 unique_commit f1 tree -p f2
-on_committer_date "1971-08-16 00:00:09" save_tag e4 unique_commit e4 tree -p e5
-on_committer_date "1971-08-16 00:00:10" save_tag e3 unique_commit e3 tree -p e4
-on_committer_date "1971-08-16 00:00:11" save_tag e2 unique_commit e2 tree -p e3
-on_committer_date "1971-08-16 00:00:12" save_tag e1 unique_commit e1 tree -p e2
-on_committer_date "1971-08-16 00:00:13" save_tag E unique_commit E tree -p e1 -p f1
-
-on_committer_date "1971-08-16 00:00:00" hide_error save_tag U unique_commit U tree
-on_committer_date "1971-08-16 00:00:01" save_tag u0 unique_commit u0 tree -p U
-on_committer_date "1971-08-16 00:00:01" save_tag u1 unique_commit u1 tree -p u0
-on_committer_date "1971-08-16 00:00:02" save_tag u2 unique_commit u2 tree -p u0
-on_committer_date "1971-08-16 00:00:03" save_tag u3 unique_commit u3 tree -p u0
-on_committer_date "1971-08-16 00:00:04" save_tag u4 unique_commit u4 tree -p u0
-on_committer_date "1971-08-16 00:00:05" save_tag u5 unique_commit u5 tree -p u0
-on_committer_date "1971-08-16 00:00:06" save_tag V unique_commit V tree -p u1 -p u2 -p u3 -p u4 -p u5
+on_committer_date "00:00" hide_error save_tag F unique_commit F tree
+on_committer_date "00:01" save_tag e8 unique_commit e8 tree -p F
+on_committer_date "00:02" save_tag e7 unique_commit e7 tree -p e8
+on_committer_date "00:03" save_tag e6 unique_commit e6 tree -p e7
+on_committer_date "00:04" save_tag e5 unique_commit e5 tree -p e6
+on_committer_date "00:05" save_tag f4 unique_commit f4 tree -p F
+on_committer_date "00:06" save_tag f3 unique_commit f3 tree -p f4
+on_committer_date "00:07" save_tag f2 unique_commit f2 tree -p f3
+on_committer_date "00:08" save_tag f1 unique_commit f1 tree -p f2
+on_committer_date "00:09" save_tag e4 unique_commit e4 tree -p e5
+on_committer_date "00:10" save_tag e3 unique_commit e3 tree -p e4
+on_committer_date "00:11" save_tag e2 unique_commit e2 tree -p e3
+on_committer_date "00:12" save_tag e1 unique_commit e1 tree -p e2
+on_committer_date "00:13" save_tag E unique_commit E tree -p e1 -p f1
+
+on_committer_date "00:00" hide_error save_tag U unique_commit U tree
+on_committer_date "00:01" save_tag u0 unique_commit u0 tree -p U
+on_committer_date "00:01" save_tag u1 unique_commit u1 tree -p u0
+on_committer_date "00:02" save_tag u2 unique_commit u2 tree -p u0
+on_committer_date "00:03" save_tag u3 unique_commit u3 tree -p u0
+on_committer_date "00:04" save_tag u4 unique_commit u4 tree -p u0
+on_committer_date "00:05" save_tag u5 unique_commit u5 tree -p u0
+on_committer_date "00:06" save_tag V unique_commit V tree -p u1 -p u2 -p u3 -p u4 -p u5
 
 test_sequence()
 {
diff --git a/t/t6003-rev-list-topo-order.sh b/t/t6003-rev-list-topo-order.sh
index e4c52b0..24d1836 100755
--- a/t/t6003-rev-list-topo-order.sh
+++ b/t/t6003-rev-list-topo-order.sh
@@ -16,39 +16,34 @@ list_duplicates()
 date >path0
 git update-index --add path0
 save_tag tree git write-tree
-on_committer_date "1971-08-16 00:00:00" hide_error save_tag root unique_commit root tree
-on_committer_date "1971-08-16 00:00:01" save_tag l0 unique_commit l0 tree -p root
-on_committer_date "1971-08-16 00:00:02" save_tag l1 unique_commit l1 tree -p l0
-on_committer_date "1971-08-16 00:00:03" save_tag l2 unique_commit l2 tree -p l1
-on_committer_date "1971-08-16 00:00:04" save_tag a0 unique_commit a0 tree -p l2
-on_committer_date "1971-08-16 00:00:05" save_tag a1 unique_commit a1 tree -p a0
-on_committer_date "1971-08-16 00:00:06" save_tag b1 unique_commit b1 tree -p a0
-on_committer_date "1971-08-16 00:00:07" save_tag c1 unique_commit c1 tree -p b1
-on_committer_date "1971-08-16 00:00:08" as_author foobar@example.com save_tag b2 unique_commit b2 tree -p b1
-on_committer_date "1971-08-16 00:00:09" save_tag b3 unique_commit b3 tree -p b2
-on_committer_date "1971-08-16 00:00:10" save_tag c2 unique_commit c2 tree -p c1 -p b2
-on_committer_date "1971-08-16 00:00:11" save_tag c3 unique_commit c3 tree -p c2
-on_committer_date "1971-08-16 00:00:12" save_tag a2 unique_commit a2 tree -p a1
-on_committer_date "1971-08-16 00:00:13" save_tag a3 unique_commit a3 tree -p a2
-on_committer_date "1971-08-16 00:00:14" save_tag b4 unique_commit b4 tree -p b3 -p a3
-on_committer_date "1971-08-16 00:00:15" save_tag a4 unique_commit a4 tree -p a3 -p b4 -p c3
-on_committer_date "1971-08-16 00:00:16" save_tag l3 unique_commit l3 tree -p a4
-on_committer_date "1971-08-16 00:00:17" save_tag l4 unique_commit l4 tree -p l3
-on_committer_date "1971-08-16 00:00:18" save_tag l5 unique_commit l5 tree -p l4
-on_committer_date "1971-08-16 00:00:19" save_tag m1 unique_commit m1 tree -p a4 -p c3
-on_committer_date "1971-08-16 00:00:20" save_tag m2 unique_commit m2 tree -p c3 -p a4
-on_committer_date "1971-08-16 00:00:21" hide_error save_tag alt_root unique_commit alt_root tree
-on_committer_date "1971-08-16 00:00:22" save_tag r0 unique_commit r0 tree -p alt_root
-on_committer_date "1971-08-16 00:00:23" save_tag r1 unique_commit r1 tree -p r0
-on_committer_date "1971-08-16 00:00:24" save_tag l5r1 unique_commit l5r1 tree -p l5 -p r1
-on_committer_date "1971-08-16 00:00:25" save_tag r1l5 unique_commit r1l5 tree -p r1 -p l5
+on_dates "00:00" "00:00" hide_error save_tag root unique_commit root tree
+on_dates "00:01" "00:01" save_tag l0 unique_commit l0 tree -p root
+on_dates "00:02" "00:02" save_tag l1 unique_commit l1 tree -p l0
+on_dates "00:03" "00:03" save_tag l2 unique_commit l2 tree -p l1
+on_dates "00:04" "00:04" save_tag a0 unique_commit a0 tree -p l2
+on_dates "00:05" "00:05" save_tag a1 unique_commit a1 tree -p a0
+on_dates "00:06" "00:06" save_tag b1 unique_commit b1 tree -p a0
+on_dates "00:07" "00:07" save_tag c1 unique_commit c1 tree -p b1
+on_dates "00:08" "00:08" as_author foobar@example.com save_tag b2 unique_commit b2 tree -p b1
+on_dates "00:09" "00:09" save_tag b3 unique_commit b3 tree -p b2
+on_dates "00:10" "00:10" save_tag c2 unique_commit c2 tree -p c1 -p b2
+on_dates "00:11" "00:11" save_tag c3 unique_commit c3 tree -p c2
+on_dates "00:12" "00:00" save_tag a2 unique_commit a2 tree -p a1
+on_dates "00:13" "00:01" save_tag a3 unique_commit a3 tree -p a2
+on_dates "00:14" "00:14" save_tag b4 unique_commit b4 tree -p b3 -p a3
+on_dates "00:15" "00:15" save_tag a4 unique_commit a4 tree -p a3 -p b4 -p c3
+on_dates "00:16" "00:16" save_tag l3 unique_commit l3 tree -p a4
+on_dates "00:17" "00:17" save_tag l4 unique_commit l4 tree -p l3
+on_dates "00:18" "00:18" save_tag l5 unique_commit l5 tree -p l4
+on_dates "00:19" "00:19" save_tag m1 unique_commit m1 tree -p a4 -p c3
+on_dates "00:20" "00:20" save_tag m2 unique_commit m2 tree -p c3 -p a4
+on_dates "00:21" "00:21" hide_error save_tag alt_root unique_commit alt_root tree
+on_dates "00:22" "00:22" save_tag r0 unique_commit r0 tree -p alt_root
+on_dates "00:23" "00:23" save_tag r1 unique_commit r1 tree -p r0
+on_dates "00:24" "00:24" save_tag l5r1 unique_commit l5r1 tree -p l5 -p r1
+on_dates "00:25" "00:25" save_tag r1l5 unique_commit r1l5 tree -p r1 -p l5
 
 
-#
-# note: as of 20/6, it isn't possible to create duplicate parents, so this
-# can't be tested.
-#
-#on_committer_date "1971-08-16 00:00:20" save_tag m3 unique_commit m3 tree -p c3 -p a4 -p c3
 hide_error save_tag e1 as_author e@example.com unique_commit e1 tree
 save_tag e2 as_author e@example.com unique_commit e2 tree -p e1
 save_tag f1 as_author f@example.com unique_commit f1 tree -p e1
@@ -105,6 +100,50 @@ l0
 root
 EOF
 
+test_output_expect_success 'simple date order' 'git rev-list --date-order  HEAD' <<EOF
+l5
+l4
+l3
+a4
+b4
+a3
+a2
+c3
+c2
+b3
+b2
+c1
+b1
+a1
+a0
+l2
+l1
+l0
+root
+EOF
+
+test_output_expect_success 'simple author-date order' 'git rev-list --author-date-order  HEAD' <<EOF
+l5
+l4
+l3
+a4
+b4
+c3
+c2
+b3
+b2
+c1
+b1
+a3
+a2
+a1
+a0
+l2
+l1
+l0
+root
+EOF
+
 test_output_expect_success 'two diamonds topo order (g6)' 'git rev-list --topo-order  g4' <<EOF
 g4
 h2