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vi: correctly detect when a deletion empties the buffer

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Michał Berger has reported two issues:

- Repeatedly deleting and undoing the deletion of the last line
  results in characters being lost from the end of the line.

- Deleting the bottom line twice then attempting to undo each of
  these deletions results in a segfault.

The problem seems to be an incorrect test for whether the text buffer
is empty.

Reported-by: Michał Berger <michallinuxstuff@gmail.com>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2018-12-03 10:07:58 +01:00 committed by Denys Vlasenko
parent b733046069
commit d08206dce1
1 changed files with 1 additions and 1 deletions
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2
editors/vi.c
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@ -2364,7 +2364,7 @@ static void undo_push(char *src, unsigned int length, uint8_t u_type) // Add to
// Allocate a new undo object // Allocate a new undo object
if (u_type == UNDO_DEL || u_type == UNDO_DEL_CHAIN) { if (u_type == UNDO_DEL || u_type == UNDO_DEL_CHAIN) {
// For UNDO_DEL objects, save deleted text // For UNDO_DEL objects, save deleted text
if ((src + length) == end) if ((text + length) == end)
length--; length--;
// If this deletion empties text[], strip the newline. When the buffer becomes // If this deletion empties text[], strip the newline. When the buffer becomes
// zero-length, a newline is added back, which requires this to compensate. // zero-length, a newline is added back, which requires this to compensate.