git
diff --git a/‎diff.c‎
Lines changed: 4 additions & 8 deletions b/‎diff.c‎
Lines changed: 4 additions & 8 deletions
diff --git a/‎t/t4052-stat-output.sh‎
Lines changed: 32 additions & 0 deletions b/‎t/t4052-stat-output.sh‎
Lines changed: 32 additions & 0 deletions
@@ -2756,7 +2756,9 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	count = i; /* where we can stop scanning in data->files[] */
 
 	/*
-	 * We have width = stat_width or term_columns() columns total.
+	 * We have width = stat_width or term_columns() columns total minus the
+	 * length of line_prefix skipping ANSI escape codes to get the display
+	 * width (e.g., skip ANSI-colored strings in "log --graph --stat").
 	 * We want a maximum of min(max_len, stat_name_width) for the name part.
 	 * We want a maximum of min(max_change, stat_graph_width) for the +- part.
 	 * We also need 1 for " " and 4 + decimal_width(max_change)
@@ -2783,14 +2785,8 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	 * separators and this message, this message will "overflow"
 	 * making the line longer than the maximum width.
 	 */
-
-	/*
-	 * NEEDSWORK: line_prefix is often used for "log --graph" output
-	 * and contains ANSI-colored string.  utf8_strnwidth() should be
-	 * used to correctly count the display width instead of strlen().
-	 */
 	if (options->stat_width == -1)
-		width = term_columns() - strlen(line_prefix);
+		width = term_columns() - utf8_strnwidth(line_prefix, strlen(line_prefix), 1);
 	else
 		width = options->stat_width ? options->stat_width : 80;
 	number_width = decimal_width(max_change) > number_width ?
 
@@ -413,4 +413,36 @@ test_expect_success 'merge --stat respects COLUMNS with long name' '
 	test_cmp expect actual
 '
 
+# We want git-log to print only 1 commit containing a single branch graph and a
+# diffstat (the diffstat display width, when not manually set through the
+# option "--stat-width", will be automatically calculated).
+# The diffstat will be only one file, with a placeholder FILENAME, that, with
+# enough terminal display width, will contain the following line:
+#     "<RED>|<RESET>  ${FILENAME} | 0"
+# where "<RED>" and "<RESET>" are ANSI escape codes to color the text.
+# To calculate the minimium terminal display width MIN_TERM_WIDTH so that the
+# FILENAME in the diffstat will not be shortened, we take the FILENAME length
+# and add 9 to it.
+# To check if the diffstat width, when the line_prefix (the "<RED>|<RESET>" of
+# the graph) contains ANSI escape codes (the ANSI escape codes to color the
+# text), is calculated correctly, we:
+#     1. check if it contains the line defined before when using MIN_TERM_WIDTH
+#     2. check if it contains the line defined before, but with the FILENAME
+#        shortened by only one character, when using MIN_TERM_WIDTH - 1
+
+test_expect_success 'diffstat where line_prefix contains ANSI escape codes is correct width' '
+	FILENAME="placeholder-text-placeholder-text" &&
+	FILENAME_TRIMMED="...eholder-text-placeholder-text" &&
+	MIN_TERM_WIDTH=$((${#FILENAME} + 9)) &&
+	test_config color.diff always &&
+	git commit --allow-empty --allow-empty-message &&
+	>${FILENAME} &&
+	git add ${FILENAME} &&
+	git commit --allow-empty-message &&
+	COLUMNS=$((MIN_TERM_WIDTH)) git log --graph --stat -n1 | test_decode_color >out &&
+	test_grep "<RED>|<RESET>  ${FILENAME} | 0" out &&
+	COLUMNS=$((MIN_TERM_WIDTH - 1)) git log --graph --stat -n1 | test_decode_color >out &&
+	test_grep "<RED>|<RESET>  ${FILENAME_TRIMMED} | 0" out
+'
+
 test_done