log: fix coloring of certain octopus merge shapes

For octopus merges where the first parent edge immediately merges into
the next column to the left, the number of columns should be one less
than the usual case.

First parent to the left case:

| *-.
| |\ \
|/ / /

The usual case:

| *-.
| |\ \
| | | *

Also refactor the code to iterate over columns rather than dashes,
building from an initial patch suggested by Jeff King.

Signed-off-by: Noam Postavsky <npostavs@users.sourceforge.net>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/t/t4214-log-graph-octopus.sh b/t/t4214-log-graph-octopus.sh
new file mode 100755
index 0000000000..dab96c89aa
--- /dev/null
+++ b/t/t4214-log-graph-octopus.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+
+test_description='git log --graph of skewed left octopus merge.'
+
+. ./test-lib.sh
+
+test_expect_success 'set up merge history' '
+	cat >expect.uncolored <<-\EOF &&
+	* left
+	| *---.   octopus-merge
+	| |\ \ \
+	|/ / / /
+	| | | * 4
+	| | * | 3
+	| | |/
+	| * | 2
+	| |/
+	* | 1
+	|/
+	* initial
+	EOF
+	cat >expect.colors <<-\EOF &&
+	* left
+	<RED>|<RESET> *<BLUE>-<RESET><BLUE>-<RESET><MAGENTA>-<RESET><MAGENTA>.<RESET>   octopus-merge
+	<RED>|<RESET> <RED>|<RESET><YELLOW>\<RESET> <BLUE>\<RESET> <MAGENTA>\<RESET>
+	<RED>|<RESET><RED>/<RESET> <YELLOW>/<RESET> <BLUE>/<RESET> <MAGENTA>/<RESET>
+	<RED>|<RESET> <YELLOW>|<RESET> <BLUE>|<RESET> * 4
+	<RED>|<RESET> <YELLOW>|<RESET> * <MAGENTA>|<RESET> 3
+	<RED>|<RESET> <YELLOW>|<RESET> <MAGENTA>|<RESET><MAGENTA>/<RESET>
+	<RED>|<RESET> * <MAGENTA>|<RESET> 2
+	<RED>|<RESET> <MAGENTA>|<RESET><MAGENTA>/<RESET>
+	* <MAGENTA>|<RESET> 1
+	<MAGENTA>|<RESET><MAGENTA>/<RESET>
+	* initial
+	EOF
+	test_commit initial &&
+	for i in 1 2 3 4 ; do
+		git checkout master -b $i || return $?
+		# Make tag name different from branch name, to avoid
+		# ambiguity error when calling checkout.
+		test_commit $i $i $i tag$i || return $?
+	done &&
+	git checkout 1 -b merge &&
+	test_tick &&
+	git merge -m octopus-merge 1 2 3 4 &&
+	git checkout 1 -b L &&
+	test_commit left
+'
+
+test_expect_success 'log --graph with tricky octopus merge with colors' '
+	test_config log.graphColors red,green,yellow,blue,magenta,cyan &&
+	git log --color=always --graph --date-order --pretty=tformat:%s --all >actual.colors.raw &&
+	test_decode_color <actual.colors.raw | sed "s/ *\$//" >actual.colors &&
+	test_cmp expect.colors actual.colors
+'
+
+test_expect_success 'log --graph with tricky octopus merge, no color' '
+	git log --color=never --graph --date-order --pretty=tformat:%s --all >actual.raw &&
+	sed "s/ *\$//" actual.raw >actual &&
+	test_cmp expect.uncolored actual
+'
+
+# Repeat the previous two tests with "normal" octopus merge (i.e.,
+# without the first parent skewing to the "left" branch column).
+
+test_expect_success 'log --graph with normal octopus merge, no color' '
+	cat >expect.uncolored <<-\EOF &&
+	*---.   octopus-merge
+	|\ \ \
+	| | | * 4
+	| | * | 3
+	| | |/
+	| * | 2
+	| |/
+	* | 1
+	|/
+	* initial
+	EOF
+	git log --color=never --graph --date-order --pretty=tformat:%s merge >actual.raw &&
+	sed "s/ *\$//" actual.raw >actual &&
+	test_cmp expect.uncolored actual
+'
+
+test_expect_success 'log --graph with normal octopus merge with colors' '
+	cat >expect.colors <<-\EOF &&
+	*<YELLOW>-<RESET><YELLOW>-<RESET><BLUE>-<RESET><BLUE>.<RESET>   octopus-merge
+	<RED>|<RESET><GREEN>\<RESET> <YELLOW>\<RESET> <BLUE>\<RESET>
+	<RED>|<RESET> <GREEN>|<RESET> <YELLOW>|<RESET> * 4
+	<RED>|<RESET> <GREEN>|<RESET> * <BLUE>|<RESET> 3
+	<RED>|<RESET> <GREEN>|<RESET> <BLUE>|<RESET><BLUE>/<RESET>
+	<RED>|<RESET> * <BLUE>|<RESET> 2
+	<RED>|<RESET> <BLUE>|<RESET><BLUE>/<RESET>
+	* <BLUE>|<RESET> 1
+	<BLUE>|<RESET><BLUE>/<RESET>
+	* initial
+	EOF
+	test_config log.graphColors red,green,yellow,blue,magenta,cyan &&
+	git log --color=always --graph --date-order --pretty=tformat:%s merge >actual.colors.raw &&
+	test_decode_color <actual.colors.raw | sed "s/ *\$//" >actual.colors &&
+	test_cmp expect.colors actual.colors
+'
+test_done