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Fortran: fix catastrophic backtracking
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\\\\|\\. is like \\. but causes catastrophic backtracking inside (...)* .
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@jeanas
jeanas committed Aug 14, 2022
1 parent 9bd072d commit d9278a5
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Showing 3 changed files with 116 additions and 2 deletions.
2 changes: 2 additions & 0 deletions CHANGES
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Expand Up @@ -24,6 +24,8 @@ Version 2.13.0
* Coq: add some common keywords, improve recognition of ``Set``
and qualified identifiers (#2158)
* F*: Allow C-style comments anywhere in a line
* Fortran: fix catastrophic backtracking with backslashes in strings
(#2194)
* Go: add support for generics (#2167)
* Inform: update for version 6.40 (#2190)
* Isabelle: recognize cartouches (#2089)
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4 changes: 2 additions & 2 deletions pygments/lexers/fortran.py
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Expand Up @@ -157,8 +157,8 @@ class FortranLexer(RegexLexer):
],

'strings': [
(r'(?s)"(\\\\|\\[0-7]+|\\.|[^"\\])*"', String.Double),
(r"(?s)'(\\\\|\\[0-7]+|\\.|[^'\\])*'", String.Single),
(r'(?s)"(\\[0-7]+|\\[^0-7\n]|[^"\\])*"', String.Double),
(r"(?s)'(\\[0-7]+|\\[^0-7\n]|[^'\\])*'", String.Single),
],

'nums': [
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112 changes: 112 additions & 0 deletions tests/snippets/fortran/test_string_cataback.txt
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---input---
! Bad string, there isn't an even number of backslashes.
! This should not cause catastrophic backtracking.
'\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'

---tokens---
"! Bad string, there isn't an even number of backslashes.\n" Comment

'! This should not cause catastrophic backtracking.\n' Comment

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'\n' Text.Whitespace

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