Merge branch 'hn/highlight-sideband-keywords'

The sideband code learned to optionally paint selected keywords at
the beginning of incoming lines on the receiving end.

* hn/highlight-sideband-keywords:
  sideband: do not read beyond the end of input
  sideband: highlight keywords in remote sideband output

5 files changed, 235 insertions, 9 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 1c78df7b90..1c42364988 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1297,6 +1297,18 @@ color.push::
 color.push.error::
 	Use customized color for push errors.
 
+color.remote::
+	If set, keywords at the start of the line are highlighted. The
+	keywords are "error", "warning", "hint" and "success", and are
+	matched case-insensitively. May be set to `always`, `false` (or
+	`never`) or `auto` (or `true`). If unset, then the value of
+	`color.ui` is used (`auto` by default).
+
+color.remote.<slot>::
+	Use customized color for each remote keyword. `<slot>` may be
+	`hint`, `warning`, `success` or `error` which match the
+	corresponding keyword.
+
 color.showBranch::
 	A boolean to enable/disable color in the output of
 	linkgit:git-show-branch[1]. May be set to `always`,
diff --git a/help.c b/help.c
index 9c0b5a8de9..96f6d221ed 100644
--- a/help.c
+++ b/help.c
@@ -425,6 +425,7 @@ void list_config_help(int for_human)
 		{ "color.diff", "<slot>", list_config_color_diff_slots },
 		{ "color.grep", "<slot>", list_config_color_grep_slots },
 		{ "color.interactive", "<slot>", list_config_color_interactive_slots },
+		{ "color.remote", "<slot>", list_config_color_sideband_slots },
 		{ "color.status", "<slot>", list_config_color_status_slots },
 		{ "fsck", "<msg-id>", list_config_fsck_msg_ids },
 		{ "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
diff --git a/help.h b/help.h
index f8b15323a6..9eab6a3f89 100644
--- a/help.h
+++ b/help.h
@@ -83,6 +83,7 @@ void list_config_color_diff_slots(struct string_list *list, const char *prefix);
 void list_config_color_grep_slots(struct string_list *list, const char *prefix);
 void list_config_color_interactive_slots(struct string_list *list, const char *prefix);
 void list_config_color_status_slots(struct string_list *list, const char *prefix);
+void list_config_color_sideband_slots(struct string_list *list, const char *prefix);
 void list_config_fsck_msg_ids(struct string_list *list, const char *prefix);
 
 #endif /* HELP_H */
diff --git a/sideband.c b/sideband.c
index 325bf0e974..368647acf8 100644
--- a/sideband.c
+++ b/sideband.c
@@ -1,6 +1,113 @@
 #include "cache.h"
+#include "color.h"
+#include "config.h"
 #include "pkt-line.h"
 #include "sideband.h"
+#include "help.h"
+
+struct keyword_entry {
+	/*
+	 * We use keyword as config key so it should be a single alphanumeric word.
+	 */
+	const char *keyword;
+	char color[COLOR_MAXLEN];
+};
+
+static struct keyword_entry keywords[] = {
+	{ "hint",	GIT_COLOR_YELLOW },
+	{ "warning",	GIT_COLOR_BOLD_YELLOW },
+	{ "success",	GIT_COLOR_BOLD_GREEN },
+	{ "error",	GIT_COLOR_BOLD_RED },
+};
+
+/* Returns a color setting (GIT_COLOR_NEVER, etc). */
+static int use_sideband_colors(void)
+{
+	static int use_sideband_colors_cached = -1;
+
+	const char *key = "color.remote";
+	struct strbuf sb = STRBUF_INIT;
+	char *value;
+	int i;
+
+	if (use_sideband_colors_cached >= 0)
+		return use_sideband_colors_cached;
+
+	if (!git_config_get_string(key, &value)) {
+		use_sideband_colors_cached = git_config_colorbool(key, value);
+	} else if (!git_config_get_string("color.ui", &value)) {
+		use_sideband_colors_cached = git_config_colorbool("color.ui", value);
+	} else {
+		use_sideband_colors_cached = GIT_COLOR_AUTO;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(keywords); i++) {
+		strbuf_reset(&sb);
+		strbuf_addf(&sb, "%s.%s", key, keywords[i].keyword);
+		if (git_config_get_string(sb.buf, &value))
+			continue;
+		if (color_parse(value, keywords[i].color))
+			continue;
+	}
+	strbuf_release(&sb);
+	return use_sideband_colors_cached;
+}
+
+void list_config_color_sideband_slots(struct string_list *list, const char *prefix)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(keywords); i++)
+		list_config_item(list, prefix, keywords[i].keyword);
+}
+
+/*
+ * Optionally highlight one keyword in remote output if it appears at the start
+ * of the line. This should be called for a single line only, which is
+ * passed as the first N characters of the SRC array.
+ *
+ * NEEDSWORK: use "size_t n" instead for clarity.
+ */
+static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
+{
+	int i;
+
+	if (!want_color_stderr(use_sideband_colors())) {
+		strbuf_add(dest, src, n);
+		return;
+	}
+
+	while (0 < n && isspace(*src)) {
+		strbuf_addch(dest, *src);
+		src++;
+		n--;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(keywords); i++) {
+		struct keyword_entry *p = keywords + i;
+		int len = strlen(p->keyword);
+
+		if (n <= len)
+			continue;
+		/*
+		 * Match case insensitively, so we colorize output from existing
+		 * servers regardless of the case that they use for their
+		 * messages. We only highlight the word precisely, so
+		 * "successful" stays uncolored.
+		 */
+		if (!strncasecmp(p->keyword, src, len) && !isalnum(src[len])) {
+			strbuf_addstr(dest, p->color);
+			strbuf_add(dest, src, len);
+			strbuf_addstr(dest, GIT_COLOR_RESET);
+			n -= len;
+			src += len;
+			break;
+		}
+	}
+
+	strbuf_add(dest, src, n);
+}
+
 
 /*
  * Receive multiplexed output stream over git native protocol.
@@ -48,8 +155,10 @@ int recv_sideband(const char *me, int in_stream, int out)
 		len--;
 		switch (band) {
 		case 3:
-			strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
-				    DISPLAY_PREFIX, buf + 1);
+			strbuf_addf(&outbuf, "%s%s", outbuf.len ? "\n" : "",
+				    DISPLAY_PREFIX);
+			maybe_colorize_sideband(&outbuf, buf + 1, len);
+
 			retval = SIDEBAND_REMOTE_ERROR;
 			break;
 		case 2:
@@ -69,20 +178,22 @@ int recv_sideband(const char *me, int in_stream, int out)
 				if (!outbuf.len)
 					strbuf_addstr(&outbuf, DISPLAY_PREFIX);
 				if (linelen > 0) {
-					strbuf_addf(&outbuf, "%.*s%s%c",
-						    linelen, b, suffix, *brk);
-				} else {
-					strbuf_addch(&outbuf, *brk);
+					maybe_colorize_sideband(&outbuf, b, linelen);
+					strbuf_addstr(&outbuf, suffix);
 				}
+
+				strbuf_addch(&outbuf, *brk);
 				xwrite(2, outbuf.buf, outbuf.len);
 				strbuf_reset(&outbuf);
 
 				b = brk + 1;
 			}
 
-			if (*b)
-				strbuf_addf(&outbuf, "%s%s", outbuf.len ?
-					    "" : DISPLAY_PREFIX, b);
+			if (*b) {
+				strbuf_addstr(&outbuf, outbuf.len ?
+					    "" : DISPLAY_PREFIX);
+				maybe_colorize_sideband(&outbuf, b, strlen(b));
+			}
 			break;
 		case 1:
 			write_or_die(out, buf + 1, len);
diff --git a/t/t5409-colorize-remote-messages.sh b/t/t5409-colorize-remote-messages.sh
new file mode 100755
index 0000000000..f81b6813c0
--- /dev/null
+++ b/t/t5409-colorize-remote-messages.sh
@@ -0,0 +1,101 @@
+#!/bin/sh
+
+test_description='remote messages are colorized on the client'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir .git/hooks &&
+	write_script .git/hooks/update <<-\EOF &&
+	echo error: error
+	echo ERROR: also highlighted
+	echo hint: hint
+	echo hinting: not highlighted
+	echo success: success
+	echo warning: warning
+	echo prefixerror: error
+	echo " " "error: leading space"
+	echo "    "
+	echo Err
+	exit 0
+	EOF
+	echo 1 >file &&
+	git add file &&
+	git commit -m 1 &&
+	git clone . child &&
+	(
+		cd child &&
+		test_commit message2 file content2
+	)
+'
+
+test_expect_success 'keywords' '
+	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/keywords 2>output &&
+	test_decode_color <output >decoded &&
+	grep "<BOLD;RED>error<RESET>: error" decoded &&
+	grep "<YELLOW>hint<RESET>:" decoded &&
+	grep "<BOLD;GREEN>success<RESET>:" decoded &&
+	grep "<BOLD;YELLOW>warning<RESET>:" decoded
+'
+
+test_expect_success 'whole words at line start' '
+	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/whole-words 2>output &&
+	test_decode_color <output >decoded &&
+	grep "<YELLOW>hint<RESET>:" decoded &&
+	grep "hinting: not highlighted" decoded &&
+	grep "prefixerror: error" decoded
+'
+
+test_expect_success 'short line' '
+	git -C child -c color.remote=always push -f origin HEAD:short-line 2>output &&
+	test_decode_color <output >decoded &&
+	grep "remote: Err" decoded
+'
+
+test_expect_success 'case-insensitive' '
+	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/case-insensitive 2>output &&
+	cat output &&
+	test_decode_color <output >decoded &&
+	grep "<BOLD;RED>error<RESET>: error" decoded &&
+	grep "<BOLD;RED>ERROR<RESET>: also highlighted" decoded
+'
+
+test_expect_success 'leading space' '
+	git --git-dir child/.git -c color.remote=always push -f origin HEAD:refs/heads/leading-space 2>output &&        cat output &&
+	test_decode_color <output >decoded &&
+	grep "  <BOLD;RED>error<RESET>: leading space" decoded
+'
+
+test_expect_success 'spaces only' '
+	git -C child -c color.remote=always push -f origin HEAD:only-space 2>output &&
+	test_decode_color <output >decoded &&
+	grep "remote:     " decoded
+'
+
+test_expect_success 'no coloring for redirected output' '
+	git --git-dir child/.git push -f origin HEAD:refs/heads/redirected-output 2>output &&
+	test_decode_color <output >decoded &&
+	grep "error: error" decoded
+'
+
+test_expect_success 'push with customized color' '
+	git --git-dir child/.git -c color.remote=always -c color.remote.error=blue push -f origin HEAD:refs/heads/customized-color 2>output &&
+	test_decode_color <output >decoded &&
+	grep "<BLUE>error<RESET>:" decoded &&
+	grep "<BOLD;GREEN>success<RESET>:" decoded
+'
+
+
+test_expect_success 'error in customized color' '
+	git --git-dir child/.git -c color.remote=always -c color.remote.error=i-am-not-a-color push -f origin HEAD:refs/heads/error-customized-color 2>output &&
+	test_decode_color <output >decoded &&
+	grep "<BOLD;GREEN>success<RESET>:" decoded
+'
+
+test_expect_success 'fallback to color.ui' '
+	git --git-dir child/.git -c color.ui=always push -f origin HEAD:refs/heads/fallback-color-ui 2>output &&
+	test_decode_color <output >decoded &&
+	grep "<BOLD;RED>error<RESET>: error" decoded
+'
+
+test_done