log: add "log.follow" configuration variable

People who work on projects with mostly linear history with frequent
whole file renames may want to always use "git log --follow" when
inspecting the life of the content that live in a single path.

Teach the command to behave as if "--follow" was given from the
command line when log.follow configuration variable is set *and*
there is one (and only one) path on the command line.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 1b2e981a00..35d2d7c221 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -146,7 +146,30 @@ test_expect_success 'git log --follow' '
 	actual=$(git log --follow --pretty="format:%s" ichi) &&
 	expect=$(echo third ; echo second ; echo initial) &&
 	verbose test "$actual" = "$expect"
+'
+
+test_expect_success 'git config log.follow works like --follow' '
+	test_config log.follow true &&
+	actual=$(git log --pretty="format:%s" ichi) &&
+	expect=$(echo third ; echo second ; echo initial) &&
+	verbose test "$actual" = "$expect"
+'
 
+test_expect_success 'git config log.follow does not die with multiple paths' '
+	test_config log.follow true &&
+	git log --pretty="format:%s" ichi ein
+'
+
+test_expect_success 'git config log.follow does not die with no paths' '
+	test_config log.follow true &&
+	git log --
+'
+
+test_expect_success 'git config log.follow is overridden by --no-follow' '
+	test_config log.follow true &&
+	actual=$(git log --no-follow --pretty="format:%s" ichi) &&
+	expect="third" &&
+	verbose test "$actual" = "$expect"
 '
 
 cat > expect << EOF