git-difftool: Add '--gui' for selecting a GUI tool

Users might prefer to have git-difftool use a different
tool when run from a Git GUI.

This teaches git-difftool to honor 'diff.guitool' when
the '--gui' option is specified.  This allows users to
configure their preferred command-line diff tool in
'diff.tool' and a GUI diff tool in 'diff.guitool'.

Reference: http://article.gmane.org/gmane.comp.version-control.git/133386
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-difftool.txt b/Documentation/git-difftool.txt
index 8e9aed67d7f68c0234ee47dc147736bf3b8e5c4f..a5bce6278b6570e9feb94cfbe0f67f3814a36aa5 100644 (file)
--- a/Documentation/git-difftool.txt
+++ b/Documentation/git-difftool.txt
@@ -58,6 +58,12 @@ is set to the name of the temporary file containing the contents
 of the diff post-image.  `$BASE` is provided for compatibility
 with custom merge tool commands and has the same value as `$LOCAL`.
 
+-g::
+--gui::
+       When 'git-difftool' is invoked with the `-g` or `--gui` option
+       the default diff tool will be read from the configured
+       `diff.guitool` variable instead of `diff.tool`.
+
 See linkgit:git-diff[1] for the full list of supported options.
 
 CONFIG VARIABLES
@@ -68,6 +74,9 @@ difftool equivalents have not been defined.
 diff.tool::
        The default diff tool to use.
 
+diff.guitool::
+       The default diff tool to use when `--gui` is specified.
+
 difftool.<tool>.path::
        Override the path for the given tool.  This is useful in case
        your tool is not in the PATH.

diff --git a/git-difftool.perl b/git-difftool.perl
index ba5e60a45e2c4a8b54e6a58e656b3978dcb45633..8c836e4c76528e52b010dd37e904f132d5386000 100755 (executable)
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -15,13 +15,16 @@ use warnings;
 use Cwd qw(abs_path);
 use File::Basename qw(dirname);
 
+require Git;
+
 my $DIR = abs_path(dirname($0));
 
 
 sub usage
 {
        print << 'USAGE';
-usage: git difftool [--tool=<tool>] [-y|--no-prompt] ["git diff" options]
+usage: git difftool [-g|--gui] [-t|--tool=<tool>] [-y|--no-prompt]
+                    ["git diff" options]
 USAGE
        exit 1;
 }
@@ -63,6 +66,14 @@ sub generate_command
                        $ENV{GIT_DIFF_TOOL} = substr($arg, 7);
                        next;
                }
+               if ($arg eq '-g' || $arg eq '--gui') {
+                       my $tool = Git::command_oneline('config',
+                                                       'diff.guitool');
+                       if (length($tool)) {
+                               $ENV{GIT_DIFF_TOOL} = $tool;
+                       }
+                       next;
+               }
                if ($arg eq '-y' || $arg eq '--no-prompt') {
                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
                        delete $ENV{GIT_DIFFTOOL_PROMPT};

diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 707a0f54ae85a6095c57e2598bb5cd3fd83bceb3..9bf6c98c54f368dfc837a8c5c374021269f20707 100755 (executable)
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -19,6 +19,7 @@ remove_config_vars()
 {
        # Unset all config variables used by git-difftool
        git config --unset diff.tool
+       git config --unset diff.guitool
        git config --unset difftool.test-tool.cmd
        git config --unset difftool.prompt
        git config --unset merge.tool
@@ -77,6 +78,17 @@ test_expect_success 'difftool ignores bad --tool values' '
        test "$diff" = ""
 '
 
+test_expect_success 'difftool honors --gui' '
+       git config merge.tool bogus-tool &&
+       git config diff.tool bogus-tool &&
+       git config diff.guitool test-tool &&
+
+       diff=$(git difftool --no-prompt --gui branch) &&
+       test "$diff" = "branch" &&
+
+       restore_test_defaults
+'
+
 # Specify the diff tool using $GIT_DIFF_TOOL
 test_expect_success 'GIT_DIFF_TOOL variable' '
        git config --unset diff.tool