[GSoC PATCH v2 2/2] t4052: add test for diffstat width when prefix contains UTF-8 chars

From

LorenzoPegorari <lorenzo.pegorari2002@gmail.com>

Date

Feb 27, 2026, 16:08 UTC

Message-ID

<984fa10d728aad049d0430472e85f1ed0e5ea4de.1772136203.git.lorenzo.pegorari2002@gmail.com>

In-Reply-To

<cover.1772136203.git.lorenzo.pegorari2002@gmail.com>

This situation happens, for example, when `git log --stat --graph` is
executed:
* `--stat` will create a diffstat for each commit
* `--graph` will stuff `line_prefix` with the graph portion of the log,
  which contains UTF-8 characters (ANSI escape codes to color the text)

Signed-off-by: LorenzoPegorari <lorenzo.pegorari2002@gmail.com>
---
 t/b                    |  0
 t/t4052-stat-output.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 t/b

diff --git a/t/b b/t/b
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/t/t4052-stat-output.sh b/t/t4052-stat-output.sh
index 740bb97091..cc4665047d 100755
--- a/t/t4052-stat-output.sh
+++ b/t/t4052-stat-output.sh
@@ -413,4 +413,34 @@ test_expect_success 'merge --stat respects COLUMNS with long name' '
 	test_cmp expect actual
 '
 
+# git-log will print only 1 commit containing a single branch graph and a diffstat.
+# The diffstat will be only one file, with a placeholder FILENAME, that, with
+# enough terminal display width, will contain the following line:
+#     "<RED>|<RESET>  ${FILENAME} | 0"
+# where "<RED>" and "<RESET>" are ANSI escape codes to color the text.
+# To calculate the minimium terminal display width MIN_TERM_WIDTH so that the
+# FILENAME in the diffstat will not be shortened, we take the FILENAME length
+# and add 9 to it.
+# To check if the diffstat width, when the line_prefix (the "<RED>|<RESET>" of
+# the graph) contains UTF-8 characters (the ANSI escape codes), is calculated
+# correctly, we:
+#     1. check if it contains the line defined before when using MIN_TERM_WIDTH
+#     2. check if it contains the line defined before, but with the FILENAME
+#        shortened by only one character, when using MIN_TERM_WIDTH - 1
+
+test_expect_success 'diffstat where line_prefix contains UTF-8 chars is correct width' '
+	FILENAME="placeholder-text-placeholder-text" &&
+	FILENAME_TRIMMED="...eholder-text-placeholder-text" &&
+	MIN_TERM_WIDTH=$((${#FILENAME} + 9)) &&
+	test_config color.diff always &&
+	git commit --allow-empty --allow-empty-message &&
+	>${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

-- 
2.43.0