Merge branch 'bb/rgb-12-bit-colors' into next

The color parsing code learned to handle 12-bit RGB colors, spelled
as "#RGB" (in addition to "#RRGGBB" that is already supported).

* bb/rgb-12-bit-colors:
  color: add support for 12-bit RGB colors
  t/t4026-color: add test coverage for invalid RGB colors
  t/t4026-color: remove an extra double quote character

Documentation/config.txt

@@ -316,7 +316,8 @@ terminals, this is usually not the same as setting to "white black".
 Colors may also be given as numbers between 0 and 255; these use ANSI
 256-color mode (but note that not all terminals may support this). If
 your terminal supports it, you may also specify 24-bit RGB values as
-hex, like `#ff0ab3`.
+hex, like `#ff0ab3`, or 12-bit RGB values like `#f1b`, which is
+equivalent to the 24-bit color `#ff11bb`.
 +
 The accepted attributes are `bold`, `dim`, `ul`, `blink`, `reverse`,
 `italic`, and `strike` (for crossed-out or "strikethrough" letters).

color.c

@@ -64,12 +64,16 @@ static int match_word(const char *word, int len, const char *match)
  return !strncasecmp(word, match, len) && !match[len];
 }
 
-static int get_hex_color(const char *in, unsigned char *out)
+static int get_hex_color(const char **inp, int width, unsigned char *out)
 {
+ const char *in = *inp;
  unsigned int val;
- val = (hexval(in[0]) << 4) | hexval(in[1]);
+
+ assert(width == 1 || width == 2);
+ val = (hexval(in[0]) << 4) | hexval(in[width - 1]);
  if (val & ~0xff)
  return -1;
+ *inp += width;
  *out = val;
  return 0;
 }
@@ -135,11 +139,14 @@ static int parse_color(struct color *out, const char *name, int len)
  return 0;
  }
 
- /* Try a 24-bit RGB value */
- if (len == 7 && name[0] == '#') {
- if (!get_hex_color(name + 1, &out->red) &&
- !get_hex_color(name + 3, &out->green) &&
- !get_hex_color(name + 5, &out->blue)) {
+ /* Try a 24- or 12-bit RGB value prefixed with '#' */
+ if ((len == 7 || len == 4) && name[0] == '#') {
+ int width_per_color = (len == 7) ? 2 : 1;
+ const char *color = name + 1;
+
+ if (!get_hex_color(&color, width_per_color, &out->red) &&
+ !get_hex_color(&color, width_per_color, &out->green) &&
+ !get_hex_color(&color, width_per_color, &out->blue)) {
  out->type = COLOR_RGB;
  return 0;
  }

color.h

@@ -112,7 +112,8 @@ int want_color_fd(int fd, int var);
  * Translate a Git color from 'value' into a string that the terminal can
  * interpret and store it into 'dst'. The Git color values are of the form
  * "foreground [background] [attr]" where fore- and background can be a color
- * name ("red"), a RGB code (#0xFF0000) or a 256-color-mode from the terminal.
+ * name ("red"), a RGB code (#FF0000 or #F00) or a 256-color-mode from the
+ * terminal.
  */
 int color_parse(const char *value, char *dst);
 int color_parse_mem(const char *value, int len, char *dst);

t/t4026-color.sh

@@ -96,8 +96,8 @@ test_expect_success '256 colors' '
  color "254 bold 255" "[1;38;5;254;48;5;255m"
 '
 
-test_expect_success '24-bit colors' '
- color "#ff00ff black" "[38;2;255;0;255;40m"
+test_expect_success 'RGB colors' '
+ color "#ff00ff #0f0" "[38;2;255;0;255;48;2;0;255;0m"
 '
 
 test_expect_success '"default" foreground' '
@@ -112,7 +112,7 @@ test_expect_success '"default" can be combined with attributes' '
  color "default default no-reverse bold" "[1;27;39;49m"
 '
 
-test_expect_success '"normal" yields no color at all"' '
+test_expect_success '"normal" yields no color at all' '
  color "normal black" "[40m"
 '
 
@@ -140,6 +140,26 @@ test_expect_success 'extra character after attribute' '
  invalid_color "dimX"
 '
 
+test_expect_success 'non-hex character in RGB color' '
+ invalid_color "#x23456" &&
+ invalid_color "#1x3456" &&
+ invalid_color "#12x456" &&
+ invalid_color "#123x56" &&
+ invalid_color "#1234x6" &&
+ invalid_color "#12345x" &&
+ invalid_color "#x23" &&
+ invalid_color "#1x3" &&
+ invalid_color "#12x"
+'
+
+test_expect_success 'wrong number of letters in RGB color' '
+ invalid_color "#1" &&
+ invalid_color "#23" &&
+ invalid_color "#789a" &&
+ invalid_color "#bcdef" &&
+ invalid_color "#1234567"
+'
+
 test_expect_success 'unknown color slots are ignored (diff)' '
  git config color.diff.nosuchslotwilleverbedefined white &&
  git diff --color