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Fix recently broken escape_code_length() result

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`escape_code_length()` was converted from returning a `size_t` to
returning a `maybe_t<size_t>` but that subtly broke all existing call
sites by forcing all input to go through the slow path of assuming a
zero-length escape sequence was found.

This is because all callers predicated their next action on what amounts
to `if (escape_code_length(...))` which would correctly skip the slow
path when `escape_code_length` returned zero, but after the conversion
to `maybe_t` contained not `maybe_t::none()` but rather
`maybe_t::some(0)` due to coercion of the result from the `size_t` local
`esc_seq_len` to the `maybe_t<size_t>` return value - which, when
coerced to a boolean returns *true* for `maybe_t::some(0)` rather than
false.

The regression was introduced in 7ad855a844a271770ad659622a10f9fe273566b4
and did not ship in any released versions so no harm, no foul.
This commit is contained in:
Mahmoud Al-Qudsi 2021-08-17 19:04:10 -05:00
parent daa366eb5a
commit 426fa82f8f
1 changed files with 3 additions and 2 deletions
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5
src/screen.cpp
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@ -249,7 +249,7 @@ static bool is_visual_escape_seq(const wchar_t *code, size_t *resulting_length)
/// the escape sequence based on querying terminfo and other heuristics.
maybe_t<size_t> escape_code_length(const wchar_t *code) {
assert(code != nullptr);
if (*code != L'\x1B') return 0;
if (*code != L'\x1B') return none();
size_t esc_seq_len = 0;
bool found = is_color_escape_seq(code, &esc_seq_len);
@ -259,7 +259,8 @@ maybe_t<size_t> escape_code_length(const wchar_t *code) {
if (!found) found = is_three_byte_escape_seq(code, &esc_seq_len);
if (!found) found = is_csi_style_escape_seq(code, &esc_seq_len);
if (!found) found = is_two_byte_escape_seq(code, &esc_seq_len);
return esc_seq_len;
return found ? maybe_t<size_t>{esc_seq_len} : none();
}
size_t layout_cache_t::escape_code_length(const wchar_t *code) {