<i18n dev> RFR: 8271302: Regex Test Refresh [v2]

Pavel Rappo prappo at openjdk.java.net
Fri Aug 20 14:28:25 UTC 2021

On Fri, 20 Aug 2021 13:46:39 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

>> Ian Graves has updated the pull request incrementally with one additional commit since the last revision:
>>   Couple of fixes
> test/jdk/java/util/regex/NegativeArraySize.java line 40:
>> 38:     @Test
>> 39:     public static void testNegativeArraySize() {
>> 40:         assertThrows(OutOfMemoryError.class, () -> Pattern.compile("\\Q" + "a".repeat(42 + Integer.MAX_VALUE / 3)));
> One observation on this regex. Although the regex looks invalid because `\\Q` misses the pairing `\\E`, it can still be compiled (with a reasonable number of a's, of course). Moreover, the resulting pattern matches strings in a surprising way:
> jshell> Pattern.compile("\\Qaaa").matcher("aaa").matches()
> $1 ==> true

Maybe that behavior is expected after all. From "Mastering Regular Expressions" by Jeffrey E.F. Friedl, 3rd Edition, p. 136:
> Literal-text span: `\Q...\E`
> First introduced with Perl, the special sequence `\Q...\E` turns off all regex meta-characters between them, except for `\E` itself. (If the `\E` is omitted, they are turned off until the end of the regex.)


PR: https://git.openjdk.java.net/jdk/pull/5092

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