[PATCH v3 5/5] pretty-print: teach "--no-expand-tabs" option to "git log"

[Junio C Hamano <gitster@pobox.com>]

The output formats of "git log" that indent the log message by 4
spaces have been updated to expand tabs by default in previous
steps, without a way to restore the original behaviour.

Introduce a new "--no-expand-tabs" option to allow this.

As the effect of options is cumulative,

    $ git log [--pretty=medium] --no-expand-tabs

would not expand, while this invocation

    $ git log --no-expand-tabs --pretty[=medium]

by virtue of having --pretty later on the command line, expands tabs
again.

We _could_ introduce --expand-tabs option as well, to allow

    $ git log --pretty=email --expand-tabs

but we don't bother, as the output format that do not expand tabs by
default are mostly meant to transfer the contents as literally as
possible.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
---
 Documentation/pretty-options.txt | 6 ++++++
 revision.c                       | 2 ++
 t/t4201-shortlog.sh              | 4 ++--
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/Documentation/pretty-options.txt b/Documentation/pretty-options.txt
index 4b659ac..069b927 100644
--- a/Documentation/pretty-options.txt
+++ b/Documentation/pretty-options.txt
@@ -42,6 +42,12 @@ people using 80-column terminals.
 	verbatim; this means that invalid sequences in the original
 	commit may be copied to the output.
 
+--no-expand-tabs::
+	The formats that indent the log message by 4 spaces
+	(i.e. 'medium', 'full', and 'fuller') by default show tabs
+	in the log message expanded.  This option disables the
+	expansion.
+
 ifndef::git-rev-list[]
 --notes[=<ref>]::
 	Show the notes (see linkgit:git-notes[1]) that annotate the
diff --git a/revision.c b/revision.c
index 8827d9f..b0d2a36 100644
--- a/revision.c
+++ b/revision.c
@@ -1916,6 +1916,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->verbose_header = 1;
 		revs->pretty_given = 1;
 		get_commit_format(arg+9, revs);
+	} else if (!strcmp(arg, "--no-expand-tabs")) {
+		revs->expand_tabs_in_log = 0;
 	} else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
 		revs->show_notes = 1;
 		revs->show_notes_given = 1;
diff --git a/t/t4201-shortlog.sh b/t/t4201-shortlog.sh
index d1e8259..2fec948 100755
--- a/t/t4201-shortlog.sh
+++ b/t/t4201-shortlog.sh
@@ -114,8 +114,8 @@ EOF
 	test_cmp expect out
 '
 
-test_expect_failure !MINGW 'shortlog from non-git directory' '
-	git log HEAD >log &&
+test_expect_success !MINGW 'shortlog from non-git directory' '
+	git log --no-expand-tabs HEAD >log &&
 	GIT_DIR=non-existing git shortlog -w <log >out &&
 	test_cmp expect out
 '
-- 
2.8.0-rc4-198-g3f6b64c