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patch 9.1.1258: regexp: max \U and \%U value is limited by INT_MAX

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Problem:  regexp: max \U and \%U value is limited by INT_MAX but gives a
          confusing error message (related: v8.1.0985).
Solution: give a better error message when the value reaches INT_MAX

When searching Vim allows to get up to 8 hex characters using the /\V
and /\%V regex atoms.  However, when using "/\UFFFFFFFF" the code point is
already above what an integer variable can hold, which is 2,147,483,647.

Since patch v8.1.0985, Vim already limited the max codepoint to INT_MAX
(otherwise it caused a crash in the nfa regex engine), but instead of
error'ing out it silently fell back to parse the number as a backslash
value and not as a codepoint value and as such this "/[\UFFFFFFFF]" will
happily find a "\" or an literal "F".  And this "/[\d127-\UFFFFFFFF]"
will error out as "reverse range in character class).

Interestingly, the max Unicode codepoint value is U+10FFFF which still
fits into an ordinary integer value,  which means, that we don't even
need to parse 8 hex characters, but 6 should have been enough.

However, let's not limit Vim to search for only max 6 hex characters
(which would be a backward incompatible change), but instead allow all 8
characters and only if the codepoint reaches INT_MAX, give a more
precise error message (about what the max unicode codepoint value is).
This allows to search for "[\U7FFFFFFE]" (will likely return "E486
Pattern not found") and "[/\U7FFFFFF]" now errors "E1517: Value too
large, max Unicode codepoint is U+10FFFF".

While this change is straight forward on architectures where long is 8
bytes, this is not so simple on Windows or 32bit architectures where long
is 4 bytes (and therefore the test fails there).  To account for that,
let's make use of the vimlong_T number type and make a few corresponding
changes in the regex engine code and cast the value to the expected data
type. This however may not work correctly on systems that doesn't have
the long long datatype (e.g. OpenVMS) and probably the test will fail
there.

fixes: #16949
closes: #16994

Signed-off-by: Christian Brabandt <cb@256bit.org>
This commit is contained in:
Christian Brabandt
2025-03-29 09:08:58 +01:00
parent 90e52490b3
commit f2b16986a1
9 changed files with 70 additions and 21 deletions
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7
runtime/doc/vi_diff.txt
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@ -1,4 +1,4 @@
*vi_diff.txt* For Vim version 9.1. Last change: 2024 Nov 10
*vi_diff.txt* For Vim version 9.1. Last change: 2025 Mar 28
VIM REFERENCE MANUAL by Bram Moolenaar
@ -91,8 +91,11 @@ Maximum display width Unix and Win32: 1024 characters, otherwise 255
Maximum lhs of a mapping 50 characters.
Number of different highlighting types: over 30000
Range of a Number variable: -2147483648 to 2147483647 (might be more on 64
bit systems)
bit systems) See also: |v:numbermax|,
|v:numbermin| and |v:numbersize|
Maximum length of a line in a tags file: 512 bytes.
*E1541*
Maximum value for |/\U| and |/\%U|: 2147483647 (for 32bit integer).
Information for undo and text in registers is kept in memory, thus when making
(big) changes the amount of (virtual) memory available limits the number of