The main loop in strbuf_utf8_replace() could summed up as:
while ('src' is still valid) {
1) advance 'src' to copy ANSI escape sequences
2) advance 'src' to copy/replace visible characters
}
The problem is after #1, 'src' may have reached the end of the string
(so 'src' points to NUL) and #2 will continue to copy that NUL as if
it's a normal character. Because the output is stored in a strbuf,
this NULL accounted in the 'len' field as well. Check after #1 and
break the loop if necessary.
The test does not look obvious, but the combination of %>>() should
make a call trace like this
show_log()
pretty_print_commit()
format_commit_message()
strbuf_expand()
format_commit_item()
format_and_pad_commit()
strbuf_utf8_replace()
where %C(auto)%d would insert a color reset escape sequence in the end
of the string given to strbuf_utf8_replace() and show_log() uses
fwrite() to send everything to stdout (including the incorrect NUL
inserted by strbuf_utf8_replace)
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
t/t4205-log-pretty-formats.sh | 7 +++++++
utf8.c | 3 +++
2 files changed, 10 insertions(+)
diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index 349c531..de0cc4a 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -431,6 +431,13 @@ EOF
test_cmp expected actual
'
+test_expect_success 'strbuf_utf8_replace() not producing NUL' '
+ git log --color --pretty="tformat:%<(10,trunc)%s%>>(10,ltrunc)%C(auto)%d" |
+ test_decode_color |
+ nul_to_q >actual &&
+ ! grep Q actual
+'
+
# get new digests (with no abbreviations)
head1=$(git rev-parse --verify HEAD~0) &&
head2=$(git rev-parse --verify HEAD~1) &&
diff --git a/utf8.c b/utf8.c
index b30790d..401a6a5 100644
--- a/utf8.c
+++ b/utf8.c
@@ -382,6 +382,9 @@ void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width,
dst += n;
}
+ if (src >= end)
+ break;
+
old = src;
n = utf8_width((const char**)&src, NULL);
if (!src) /* broken utf-8, do nothing */
--
2.1.0.rc0.78.gc0d8480
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