From: Jim Meyering <meyering@redhat.com>
Date: Fri, 15 Aug 2008 11:39:26 +0000 (+0200)
Subject: add boolean diff.suppress-blank-empty config option
X-Git-Tag: v1.6.1-rc1~348
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=a624eaa7820f4f9814e41e911c665a0aba2fce34;p=git.git

add boolean diff.suppress-blank-empty config option

GNU diff's --suppress-blank-empty option makes it so that diff no
longer outputs trailing white space unless the input data has it.
With this option, empty context lines are now empty also in diff -u output.
Before, they would have a single trailing space.

 * diff.c (diff_suppress_blank_empty): New global.
   (git_diff_basic_config): Set it.
   (fn_out_consume): Honor it.
 * t/t4029-diff-trailing-space.sh: New file.
 * Documentation/config.txt: Document it.

Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 676c39bb8..902067586 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -567,6 +567,10 @@ diff.autorefreshindex::
 	affects only 'git-diff' Porcelain, and not lower level
 	'diff' commands, such as 'git-diff-files'.
 
+diff.suppress-blank-empty::
+	A boolean to inhibit the standard behavior of printing a space
+	before each empty output line. Defaults to false.
+
 diff.external::
 	If this config variable is set, diff generation is not
 	performed using the internal diff machinery, but using the
diff --git a/diff.c b/diff.c
index bf5d5f15a..fe43407b7 100644
--- a/diff.c
+++ b/diff.c
@@ -20,6 +20,7 @@
 
 static int diff_detect_rename_default;
 static int diff_rename_limit_default = 200;
+static int diff_suppress_blank_empty;
 int diff_use_color_default = -1;
 static const char *external_diff_cmd_cfg;
 int diff_auto_refresh_index = 1;
@@ -176,6 +177,12 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	/* like GNU diff's --suppress-blank-empty option  */
+	if (!strcmp(var, "diff.suppress-blank-empty")) {
+		diff_suppress_blank_empty = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!prefixcmp(var, "diff.")) {
 		const char *ep = strrchr(var, '.');
 		if (ep != var + 4) {
@@ -580,6 +587,12 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 	}
 
+	if (diff_suppress_blank_empty
+	    && len == 2 && line[0] == ' ' && line[1] == '\n') {
+		line[0] = '\n';
+		len = 1;
+	}
+
 	/* This is not really necessary for now because
 	 * this codepath only deals with two-way diffs.
 	 */
diff --git a/t/t4029-diff-trailing-space.sh b/t/t4029-diff-trailing-space.sh
new file mode 100755
index 000000000..4ca65e033
--- /dev/null
+++ b/t/t4029-diff-trailing-space.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+#
+# Copyright (c) Jim Meyering
+#
+test_description='diff honors config option, diff.suppress-blank-empty'
+
+. ./test-lib.sh
+
+cat <<\EOF > exp ||
+diff --git a/f b/f
+index 5f6a263..8cb8bae 100644
+--- a/f
++++ b/f
+@@ -1,2 +1,2 @@
+
+-x
++y
+EOF
+exit 1
+
+test_expect_success \
+    "$test_description" \
+    'printf "\nx\n" > f &&
+     git add f &&
+     git commit -q -m. f &&
+     printf "\ny\n" > f &&
+     git config --bool diff.suppress-blank-empty true &&
+     git diff f > actual &&
+     test_cmp exp actual &&
+     perl -i.bak -p -e "s/^\$/ /" exp &&
+     git config --bool diff.suppress-blank-empty false &&
+     git diff f > actual &&
+     test_cmp exp actual &&
+     git config --bool --unset diff.suppress-blank-empty &&
+     git diff f > actual &&
+     test_cmp exp actual
+     '
+
+test_done