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[PATCH 14/15] pretty: respect color settings for %C placeholders

From
Jeff King <peff@peff.net>
Date
Jul 13, 2017, 15:08 UTC
Message-ID
<20170713150845.yodu6al56po662so@sigill.intra.peff.net>
In-Reply-To
<20170713145553.3epnsw23zajwg3ee@sigill.intra.peff.net>

The color placeholders have traditionally been unconditional, showing colors even when git is not otherwise configured to do so. This was not so bad for their original use, which was on the command-line (and the user could decide at that moment whether to add colors or not). But these days we have configured formats via pretty.*, and those should operate correctly in multiple contexts.

In 3082517 (log --format: teach %C(auto,black) to respect color config, 2012-12-17), we gave an extended placeholder that could be used to accomplish this. But it's rather clunky to use, because you have to specify it individually for each color (and their matching resets) in the format. We shied away from just switching the default to auto, because it is technically breaking backwards compatibility.

However, there's not really a use case for unconditional colors. The most plausible reason you would want them is to redirect "git log" output to a file. But there, the right answer is --color=always, as it does the right thing both with custom user-format colors and git-generated colors.

So let's switch to the more useful default. In the off-chance that somebody really does find a use for unconditional colors without wanting to enable the rest of git's colors, we provide a new %C(always,...) to enable the old behavior. And we can remind them of --color=always in the documentation.

Signed-off-by: Jeff King <peff@peff.net>
---
The test diff is a lot easier to read with "-w", as it moves all of the
%C(auto,...) tests into a loop that checks all three variants.
 Documentation/pretty-formats.txt | 18 +++++----
 pretty.c                         | 27 +++++++++++--
 t/t6006-rev-list-format.sh       | 84 ++++++++++++++++++++++++----------------
 3 files changed, 84 insertions(+), 45 deletions(-)
diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 4d6dac577..973d19606 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -173,13 +173,17 @@ endif::git-rev-list[]
 - '%Cblue': switch color to blue
 - '%Creset': reset color
 - '%C(...)': color specification, as described under Values in the
-  "CONFIGURATION FILE" section of linkgit:git-config[1];
-  adding `auto,` at the beginning (e.g. `%C(auto,red)`) will emit
-  color only when colors are enabled for log output (by `color.diff`,
-  `color.ui`, or `--color`, and respecting the `auto` settings of the
-  former if we are going to a terminal). `auto` alone (i.e.
-  `%C(auto)`) will turn on auto coloring on the next placeholders
-  until the color is switched again.
+  "CONFIGURATION FILE" section of linkgit:git-config[1].
+  By default, colors are shown only when enabled for log output (by
+  `color.diff`, `color.ui`, or `--color`, and respecting the `auto`
+  settings of the former if we are going to a terminal). `%C(auto,...)`
+  is accepted as a historical synonym for the default (e.g.,
+  `%C(auto,red)`). Specifying `%C(always,...) will show the colors
+  even when color is not otherwise enabled (though consider
+  just using `--color=always` to enable color for the whole output,
+  including this format and anything else git might color).  `auto`
+  alone (i.e. `%C(auto)`) will turn on auto coloring on the next
+  placeholders until the color is switched again.
 - '%m': left (`<`), right (`>`) or boundary (`-`) mark
 - '%n': newline
 - '%%': a raw '%'
diff --git a/pretty.c b/pretty.c
index e4b561c58..fd781e54f 100644
--- a/pretty.c
+++ b/pretty.c
@@ -947,6 +947,7 @@ static size_t parse_color(struct strbuf *sb, /* in UTF-8 */
 			  struct format_commit_context *c)
 {
 	const char *rest = placeholder;
+	const char *basic_color = NULL;
 
 	if (placeholder[1] == '(') {
 		const char *begin = placeholder + 2;
@@ -955,23 +956,41 @@ static size_t parse_color(struct strbuf *sb, /* in UTF-8 */
 
 		if (!end)
 			return 0;
+
 		if (skip_prefix(begin, "auto,", &begin)) {
 			if (!want_color(c->pretty_ctx->color))
 				return end - placeholder + 1;
+		} else if(skip_prefix(begin, "always,", &begin)) {
+			/* nothing to do; we do not respect want_color at all */
+		} else {
+			/* the default is the same as "auto" */
+			if (!want_color(c->pretty_ctx->color))
+				return end - placeholder + 1;
 		}
+
 		if (color_parse_mem(begin, end - begin, color) < 0)
 			die(_("unable to parse --pretty format"));
 		strbuf_addstr(sb, color);
 		return end - placeholder + 1;
 	}
+
+	/*
+	 * We handle things like "%C(red)" above; for historical reasons, there
+	 * are a few colors that can be specified without parentheses (and
+	 * they cannot support things like "auto" or "always" at all).
+	 */
 	if (skip_prefix(placeholder + 1, "red", &rest))
-		strbuf_addstr(sb, GIT_COLOR_RED);
+		basic_color = GIT_COLOR_RED;
 	else if (skip_prefix(placeholder + 1, "green", &rest))
-		strbuf_addstr(sb, GIT_COLOR_GREEN);
+		basic_color = GIT_COLOR_GREEN;
 	else if (skip_prefix(placeholder + 1, "blue", &rest))
-		strbuf_addstr(sb, GIT_COLOR_BLUE);
+		basic_color = GIT_COLOR_BLUE;
 	else if (skip_prefix(placeholder + 1, "reset", &rest))
-		strbuf_addstr(sb, GIT_COLOR_RESET);
+		basic_color = GIT_COLOR_RESET;
+
+	if (basic_color && want_color(c->pretty_ctx->color))
+		strbuf_addstr(sb, basic_color);
+
 	return rest - placeholder;
 }
 
diff --git a/t/t6006-rev-list-format.sh b/t/t6006-rev-list-format.sh
index 7b97a90ba..b326d550f 100755
--- a/t/t6006-rev-list-format.sh
+++ b/t/t6006-rev-list-format.sh
@@ -59,7 +59,10 @@ test_format () {
 }
 
 # Feed to --format to provide predictable colored sequences.
+BASIC_COLOR='%Credfoo%Creset'
+COLOR='%C(red)foo%C(reset)'
 AUTO_COLOR='%C(auto,red)foo%C(auto,reset)'
+ALWAYS_COLOR='%C(always,red)foo%C(always,reset)'
 has_color () {
 	test_decode_color <"$1" >decoded &&
 	echo "<RED>foo<RESET>" >expect &&
@@ -177,7 +180,7 @@ test_expect_success 'basic colors' '
 	<RED>foo<GREEN>bar<BLUE>baz<RESET>xyzzy
 	EOF
 	format="%Credfoo%Cgreenbar%Cbluebaz%Cresetxyzzy" &&
-	git rev-list --format="$format" -1 master >actual.raw &&
+	git rev-list --color --format="$format" -1 master >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expect actual
 '
@@ -188,48 +191,61 @@ test_expect_success 'advanced colors' '
 	<BOLD;RED;BYELLOW>foo<RESET>
 	EOF
 	format="%C(red yellow bold)foo%C(reset)" &&
-	git rev-list --format="$format" -1 master >actual.raw &&
+	git rev-list --color --format="$format" -1 master >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expect actual
 '
 
-test_expect_success '%C(auto,...) does not enable color by default' '
-	git log --format=$AUTO_COLOR -1 >actual &&
-	has_no_color actual
-'
-
-test_expect_success '%C(auto,...) enables colors for color.diff' '
-	git -c color.diff=always log --format=$AUTO_COLOR -1 >actual &&
-	has_color actual
-'
-
-test_expect_success '%C(auto,...) enables colors for color.ui' '
-	git -c color.ui=always log --format=$AUTO_COLOR -1 >actual &&
-	has_color actual
-'
+for spec in \
+	"%Cred:$BASIC_COLOR" \
+	"%C(...):$COLOR" \
+	"%C(auto,...):$AUTO_COLOR"
+do
+	desc=${spec%%:*}
+	color=${spec#*:}
+	test_expect_success "$desc does not enable color by default" '
+		git log --format=$color -1 >actual &&
+		has_no_color actual
+	'
 
-test_expect_success '%C(auto,...) respects --color' '
-	git log --format=$AUTO_COLOR -1 --color >actual &&
-	has_color actual
-'
+	test_expect_success "$desc enables colors for color.diff" '
+		git -c color.diff=always log --format=$color -1 >actual &&
+		has_color actual
+	'
 
-test_expect_success '%C(auto,...) respects --no-color' '
-	git -c color.ui=always log --format=$AUTO_COLOR -1 --no-color >actual &&
-	has_no_color actual
-'
+	test_expect_success "$desc enables colors for color.ui" '
+		git -c color.ui=always log --format=$color -1 >actual &&
+		has_color actual
+	'
 
-test_expect_success TTY '%C(auto,...) respects --color=auto (stdout is tty)' '
-	test_terminal env TERM=vt100 \
-		git log --format=$AUTO_COLOR -1 --color=auto >actual &&
-	has_color actual
-'
+	test_expect_success "$desc respects --color" '
+		git log --format=$color -1 --color >actual &&
+		has_color actual
+	'
 
-test_expect_success '%C(auto,...) respects --color=auto (stdout not tty)' '
-	(
-		TERM=vt100 && export TERM &&
-		git log --format=$AUTO_COLOR -1 --color=auto >actual &&
+	test_expect_success "$desc respects --no-color" '
+		git -c color.ui=always log --format=$color -1 --no-color >actual &&
 		has_no_color actual
-	)
+	'
+
+	test_expect_success TTY "$desc respects --color=auto (stdout is tty)" '
+		test_terminal env TERM=vt100 \
+			git log --format=$color -1 --color=auto >actual &&
+		has_color actual
+	'
+
+	test_expect_success "$desc respects --color=auto (stdout not tty)" '
+		(
+			TERM=vt100 && export TERM &&
+			git log --format=$color -1 --color=auto >actual &&
+			has_no_color actual
+		)
+	'
+done
+
+test_expect_success '%C(always,...) enables color even without tty' '
+	git log --format=$ALWAYS_COLOR -1 >actual &&
+	has_color actual
 '
 
 test_expect_success '%C(auto) respects --color' '

-- 
2.13.2.1157.gc6daca446
Previous: Jeff KingNext: Jeff King
Message 27 of 30 in “making user-format colors conditional on config/tty”
  1. 0/15 making user-format colors conditional on config/ttyJeff King, Jul 13, 2017
  2. 01/15 check return value of verify_ref_format()Jeff King, Jul 13, 2017
  3. 02/15 docs/for-each-ref: update pointer to color syntaxJeff King, Jul 13, 2017
  4. Junio C HamanoJul 13, 2017
  5. 03/15 t: use test_decode_color rather than literal ANSI codesJeff King, Jul 13, 2017
  6. Stefan BellerJul 13, 2017
  7. Jeff KingJul 13, 2017
  8. Junio C HamanoJul 13, 2017
  9. Jeff KingJul 14, 2017
  10. Junio C HamanoJul 13, 2017
  11. 04/15 ref-filter: simplify automatic color resetJeff King, Jul 13, 2017
  12. 05/15 ref-filter: abstract ref format into its own structJeff King, Jul 13, 2017
  13. Stefan BellerJul 13, 2017
  14. Junio C HamanoJul 13, 2017
  15. Junio C HamanoJul 13, 2017
  16. Stefan BellerJul 13, 2017
  17. Junio C HamanoJul 13, 2017
  18. 06/15 ref-filter: move need_color_reset_at_eol into ref_formatJeff King, Jul 13, 2017
  19. Junio C HamanoJul 13, 2017
  20. 07/15 ref-filter: provide a function for parsing sort optionsJeff King, Jul 13, 2017
  21. 08/15 ref-filter: make parse_ref_filter_atom a private functionJeff King, Jul 13, 2017
  22. 09/15 ref-filter: factor out the parsing of sorting atomsJeff King, Jul 13, 2017
  23. 10/15 ref-filter: pass ref_format struct to atom parsersJeff King, Jul 13, 2017
  24. 11/15 color: check color.ui in git_default_config()Jeff King, Jul 13, 2017
  25. 12/15 for-each-ref: load config earlierJeff King, Jul 13, 2017
  26. 13/15 rev-list: pass diffopt->use_colors through to pretty-printJeff King, Jul 13, 2017
  27. 14/15 pretty: respect color settings for %C placeholdersJeff King, Jul 13, 2017
  28. 15/15 ref-filter: consult want_color() before emitting colorsJeff King, Jul 13, 2017
  29. Stefan BellerJul 13, 2017
  30. Junio C HamanoJul 13, 2017

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