From: LorenzoPegorari Date: Fri, 27 Feb 2026 21:43:14 GMT Subject: [GSoC PATCH v3 0/2] diff: handle ANSI escape codes in prefix when calculating diffstat width Message-ID: In-Reply-To: This patch aims to fix a bug where the calculation of the diffstat width incorrectly uses the strlen() of line_prefix instead of its actual display width. This patch addresses the NEEDSWORK item added by ce8529b2 (diff: leave NEEDWORK notes in show_stats() function, 2022-10-21). Thanks Junio for you guidance. V3 DIFF: * Changed references from "UTF-8 char" to "ANSI escape codes" * Removed mistakenly added empty file * Slightly improved the test script comment LorenzoPegorari (2): diff: handle ANSI escape codes in prefix when calculating diffstat width t4052: test for diffstat width when prefix contains ANSI escape codes diff.c | 12 ++++-------- t/t4052-stat-output.sh | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 8 deletions(-) Range-diff against v2: 1: 9e8161a700 ! 1: f75d6d779e diff: handle UTF-8 chars in prefix when calculating diffstat width @@ Metadata Author: LorenzoPegorari ## Commit message ## - diff: handle UTF-8 chars in prefix when calculating diffstat width + diff: handle ANSI escape codes in prefix when calculating diffstat width The diffstat width is calculated by taking the terminal width and incorrectly subtracting the `strlen()` of `line_prefix`, instead of the - actual display width of `line_prefix`, which may contain UTF-8 - characters (e.g., ANSI-colored strings in `log --graph --stat`). + actual display width of `line_prefix`, which may contain ANSI escape + codes (e.g., ANSI-colored strings in `log --graph --stat`). Utilize the display width instead, obtained via `utf8_strnwidth()` with the flag `skip_ansi`. @@ diff.c: static void show_stats(struct diffstat_t *data, struct diff_options *opt /* - * 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 UTF-8 chars to get the display width -+ * (e.g., to skip ANSI-colored strings in "log --graph --stat"). ++ * 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) 2: 984fa10d72 ! 2: 1d55bff06e t4052: add test for diffstat width when prefix contains UTF-8 chars @@ Metadata Author: LorenzoPegorari ## Commit message ## - t4052: add test for diffstat width when prefix contains UTF-8 chars + t4052: test for diffstat width when prefix contains ANSI escape codes Add test checking the calculation of the diffstat display width when the `line_prefix`, which is text that goes before the diffstat, contains - UTF-8 characters. + ANSI escape codes. 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) + which contains ANSI escape codes to color the text Signed-off-by: LorenzoPegorari - ## t/b (new) ## - ## t/t4052-stat-output.sh ## @@ t/t4052-stat-output.sh: 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. ++# 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: +# "| ${FILENAME} | 0" @@ t/t4052-stat-output.sh: test_expect_success 'merge --stat respects COLUMNS with +# FILENAME in the diffstat will not be shortened, we take the FILENAME length +# and add 9 to it. +# To check if the diffstat width, when the line_prefix (the "|" of -+# the graph) contains UTF-8 characters (the ANSI escape codes), is calculated -+# correctly, we: ++# the graph) contains ANSI escape codes (the ANSI escape codes to color the ++# text), is calculated correctly, we: +# 1. check if it contains the line defined before when using MIN_TERM_WIDTH +# 2. check if it contains the line defined before, but with the FILENAME +# shortened by only one character, when using MIN_TERM_WIDTH - 1 + -+test_expect_success 'diffstat where line_prefix contains UTF-8 chars is correct width' ' ++test_expect_success 'diffstat where line_prefix contains ANSI escape codes is correct width' ' + FILENAME="placeholder-text-placeholder-text" && + FILENAME_TRIMMED="...eholder-text-placeholder-text" && + MIN_TERM_WIDTH=$((${#FILENAME} + 9)) && -- 2.43.0