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Code Issues 1 Releases Wiki Activity

Address issue #1539 - infinite loop in peg split

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Other looping rules ensure forward progress by terminating if an
iteration is at the same location as the previous iteration. Do the same
for split.
This commit is contained in:
Calvin Rose 2025-01-01 11:26:43 -06:00
parent f252933f62
commit 60d9f97750
2 changed files with 31 additions and 17 deletions
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35
src/core/peg.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2024 Calvin Rose
* Copyright (c) 2025 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
@ -549,36 +549,39 @@ tail:
const uint32_t *rule_separator = s->bytecode + rule[1];
const uint32_t *rule_subpattern = s->bytecode + rule[2];
const uint8_t *separator_end = NULL;
do {
const uint8_t *text_start = text;
const uint8_t *chunk_start = text;
const uint8_t *chunk_end = NULL;
while (text <= saved_end) {
/* Find next split (or end of text) */
CapState cs = cap_save(s);
down1(s);
while (text <= s->text_end) {
separator_end = peg_rule(s, rule_separator, text);
while (text <= saved_end) {
chunk_end = text;
const uint8_t *check = peg_rule(s, rule_separator, text);
cap_load(s, cs);
if (separator_end) {
if (check) {
text = check;
break;
}
text++;
}
up1(s);
if (separator_end) {
s->text_end = text;
text = separator_end;
}
/* Match between splits */
s->text_end = chunk_end;
down1(s);
const uint8_t *subpattern_end = peg_rule(s, rule_subpattern, text_start);
const uint8_t *subpattern_end = peg_rule(s, rule_subpattern, chunk_start);
up1(s);
s->text_end = saved_end;
if (!subpattern_end) return NULL; /* Don't match anything */
if (!subpattern_end) {
return NULL;
/* Ensure forward progress */
if (text == chunk_start) return NULL;
chunk_start = text;
}
} while (separator_end);
s->text_end = saved_end;
return s->text_end;
}

11
test/suite-peg.janet
View File

@ -772,5 +772,16 @@
"5:apple6:banana6:cherry"
@["apple" "banana" "cherry"])
# Issue #1539 - make sure split with "" doesn't infinite loop/oom
(test "issue 1539"
~(split "" (capture (to -1)))
"hello there friends"
nil)
(test "issue 1539 pt. 2"
~(split "," (capture 0))
"abc123,,,,"
@["" "" "" "" ""])
(end-suite)