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format-patch: wrap long header lines
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Subject and identity headers may be arbitrarily long. In the
past, we just assumed that single-line headers would be
reasonably short. For multi-line subjects that we squish
into a single line, we just "pre-folded" the data in
pp_title_line by adding a newline and indentation.

There were two problems. One is that, although rare,
single-line messages can actually be longer than the
recommended line-length limits. The second is that the
pre-folding interacted badly with rfc2047 encoding, leading
to malformed headers.

Instead, let's stop pre-folding the subject lines, and just
fold everything based on length in add_rfc2047, whether
it is encoded or not.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Jeff King authored and Junio C Hamano committed Feb 23, 2011
1 parent 98acc83 commit a1f6baa
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Showing 2 changed files with 108 additions and 8 deletions.
32 changes: 24 additions & 8 deletions pretty.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -216,7 +216,15 @@ static int is_rfc2047_special(char ch)
static void add_rfc2047(struct strbuf *sb, const char *line, int len,
const char *encoding)
{
int i, last;
static const int max_length = 78; /* per rfc2822 */
int i;
int line_len;

/* How many bytes are already used on the current line? */
for (i = sb->len - 1; i >= 0; i--)
if (sb->buf[i] == '\n')
break;
line_len = sb->len - (i+1);

for (i = 0; i < len; i++) {
int ch = line[i];
Expand All @@ -225,27 +233,36 @@ static void add_rfc2047(struct strbuf *sb, const char *line, int len,
if ((i + 1 < len) && (ch == '=' && line[i+1] == '?'))
goto needquote;
}
strbuf_add(sb, line, len);
strbuf_add_wrapped_bytes(sb, line, len, 0, 1, max_length - line_len);
return;

needquote:
strbuf_grow(sb, len * 3 + strlen(encoding) + 100);
strbuf_addf(sb, "=?%s?q?", encoding);
for (i = last = 0; i < len; i++) {
line_len += strlen(encoding) + 5; /* 5 for =??q? */
for (i = 0; i < len; i++) {
unsigned ch = line[i] & 0xFF;

if (line_len >= max_length - 2) {
strbuf_addf(sb, "?=\n =?%s?q?", encoding);
line_len = strlen(encoding) + 5 + 1; /* =??q? plus SP */
}

/*
* We encode ' ' using '=20' even though rfc2047
* allows using '_' for readability. Unfortunately,
* many programs do not understand this and just
* leave the underscore in place.
*/
if (is_rfc2047_special(ch) || ch == ' ') {
strbuf_add(sb, line + last, i - last);
strbuf_addf(sb, "=%02X", ch);
last = i + 1;
line_len += 3;
}
else {
strbuf_addch(sb, ch);
line_len++;
}
}
strbuf_add(sb, line + last, len - last);
strbuf_addstr(sb, "?=");
}

Expand Down Expand Up @@ -1106,11 +1123,10 @@ void pp_title_line(enum cmit_fmt fmt,
const char *encoding,
int need_8bit_cte)
{
const char *line_separator = (fmt == CMIT_FMT_EMAIL) ? "\n " : " ";
struct strbuf title;

strbuf_init(&title, 80);
*msg_p = format_subject(&title, *msg_p, line_separator);
*msg_p = format_subject(&title, *msg_p, " ");

strbuf_grow(sb, title.len + 1024);
if (subject) {
Expand Down
84 changes: 84 additions & 0 deletions t/t4014-format-patch.sh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -709,4 +709,88 @@ test_expect_success TTY 'format-patch --stdout paginates' '
test_path_is_missing .git/pager_used
'

test_expect_success 'format-patch handles multi-line subjects' '
rm -rf patches/ &&
echo content >>file &&
for i in one two three; do echo $i; done >msg &&
git add file &&
git commit -F msg &&
git format-patch -o patches -1 &&
grep ^Subject: patches/0001-one.patch >actual &&
echo "Subject: [PATCH] one two three" >expect &&
test_cmp expect actual
'

test_expect_success 'format-patch handles multi-line encoded subjects' '
rm -rf patches/ &&
echo content >>file &&
for i in en två tre; do echo $i; done >msg &&
git add file &&
git commit -F msg &&
git format-patch -o patches -1 &&
grep ^Subject: patches/0001-en.patch >actual &&
echo "Subject: [PATCH] =?UTF-8?q?en=20tv=C3=A5=20tre?=" >expect &&
test_cmp expect actual
'

M8="foo bar "
M64=$M8$M8$M8$M8$M8$M8$M8$M8
M512=$M64$M64$M64$M64$M64$M64$M64$M64
cat >expect <<'EOF'
Subject: [PATCH] foo bar foo bar foo bar foo bar foo bar foo bar foo bar foo
bar foo bar foo bar foo bar foo bar foo bar foo bar foo bar
foo bar foo bar foo bar foo bar foo bar foo bar foo bar foo
bar foo bar foo bar foo bar foo bar foo bar foo bar foo bar
foo bar foo bar foo bar foo bar foo bar foo bar foo bar foo
bar foo bar foo bar foo bar foo bar foo bar foo bar foo bar
foo bar foo bar foo bar foo bar foo bar foo bar foo bar foo
bar foo bar foo bar foo bar foo bar foo bar foo bar foo bar
foo bar foo bar foo bar foo bar
EOF
test_expect_success 'format-patch wraps extremely long headers (ascii)' '
echo content >>file &&
git add file &&
git commit -m "$M512" &&
git format-patch --stdout -1 >patch &&
sed -n "/^Subject/p; /^ /p; /^$/q" <patch >subject &&
test_cmp expect subject
'

M8="föö bar "
M64=$M8$M8$M8$M8$M8$M8$M8$M8
M512=$M64$M64$M64$M64$M64$M64$M64$M64
cat >expect <<'EOF'
Subject: [PATCH] =?UTF-8?q?f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
=?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
EOF
test_expect_success 'format-patch wraps extremely long headers (rfc2047)' '
rm -rf patches/ &&
echo content >>file &&
git add file &&
git commit -m "$M512" &&
git format-patch --stdout -1 >patch &&
sed -n "/^Subject/p; /^ /p; /^$/q" <patch >subject &&
test_cmp expect subject
'

test_done

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