diff: diff.context configuration gives default to -U

Introduce a configuration variable diff.context that tells
Porcelain commands to use a non-default number of context
lines instead of 3 (the default).  With this variable, users
do not have to keep repeating "git log -U8" from the command
line; instead, it becomes sufficient to say "git config
diff.context 8" just once.

Signed-off-by: Jeff Muizelaar <jmuizelaar@mozilla.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 93 insertions, 0 deletions

diff --git a/t/t4055-diff-context.sh b/t/t4055-diff-context.sh
new file mode 100755
index 0000000000..35276868ea
--- /dev/null
+++ b/t/t4055-diff-context.sh
@@ -0,0 +1,93 @@
+#!/bin/sh
+#
+# Copyright (c) 2012 Mozilla Foundation
+#
+
+test_description='diff.context configuration'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	cat >x <<-\EOF &&
+	firstline
+	b
+	c
+	d
+	e
+	f
+	preline
+	postline
+	i
+	j
+	k
+	l
+	m
+	n
+	EOF
+	git update-index --add x &&
+	git commit -m initial &&
+
+	git cat-file blob HEAD:x |
+	sed "/preline/a\
+	ADDED" >x &&
+	git update-index --add x &&
+	git commit -m next &&
+
+	git cat-file blob HEAD:x |
+	sed s/ADDED/MODIFIED/ >x
+'
+
+test_expect_success 'the default number of context lines is 3' '
+	git diff >output &&
+	! grep "^ d" output &&
+	grep "^ e" output &&
+	grep "^ j" output &&
+	! grep "^ k" output
+'
+
+test_expect_success 'diff.context honored by "log"' '
+	git log -1 -p >output &&
+	! grep firstline output &&
+	git config diff.context 8 &&
+	git log -1 -p >output &&
+	grep "^ firstline" output
+'
+
+test_expect_success 'The -U option overrides diff.context' '
+	git config diff.context 8 &&
+	git log -U4 -1 >output &&
+	! grep "^ firstline" output
+'
+
+test_expect_success 'diff.context honored by "diff"' '
+	git config diff.context 8 &&
+	git diff >output &&
+	grep "^ firstline" output
+'
+
+test_expect_success 'plumbing not affected' '
+	git config diff.context 8 &&
+	git diff-files -p >output &&
+	! grep "^ firstline" output
+'
+
+test_expect_success 'non-integer config parsing' '
+	git config diff.context no &&
+	test_must_fail git diff 2>output &&
+	test_i18ngrep "bad config value" output
+'
+
+test_expect_success 'negative integer config parsing' '
+	git config diff.context -1 &&
+	test_must_fail git diff 2>output &&
+	test_i18ngrep "bad config file" output
+'
+
+test_expect_success '-U0 is valid, so is diff.context=0' '
+	git config diff.context 0 &&
+	git diff >output &&
+	grep "^-ADDED" output &&
+	grep "^+MODIFIED" output
+'
+
+test_done