I have been able to replicate the OP's problem with go 1.21.0
==> main.go <==
package main
import (
"plugin"
//"regexp"
"regexp/syntax"
)
func main() {
//_, _ = regexp.Compile(`\w+`)
p, err := plugin.Open("p1.so")
if err != nil {
panic(err)
}
s, err := p.Lookup("F")
if err != nil {
panic(err)
}
f := s.(func() (syntax.Flags, error))
_, err = f()
if err != nil {
panic(err)
}
}
==> p1/plugin.go <==
package main
import (
"regexp"
"regexp/syntax"
)
func F() (syntax.Flags, error) {
_, err := regexp.Compile(`\w+`)
return syntax.Flags(0), err
}
func main() {}
$ go version
go version go1.21.0 linux/amd64
$ go build -buildmode=plugin ./p1 && go run main.go
panic: error parsing regexp: invalid escape sequence: `\w`
goroutine 1 [running]:
main.main()
/home/ubuntu/62430/main.go:24 +0x129
exit status 2
The problem goes away if you uncomment the two commented-out lines in
main.go
I had an idea about what might be happening. In this situation,
MustCompile is behaving like MustCompilePOSIX (which doesn't accept the \w
character class).
Package regexp/syntax defines a constant "Perl" which includes various
flags, including PerlX which allows this class:
func Compile(expr string) (*Regexp, error) {
return compile(expr, syntax.Perl, false)
}
I'm wondering if somehow this value hasn't been initialized, and is treated
as zero. However, if I print the value of syntax.Perl within main() or
F(), I see that it is 212 as expected, even when the error occurs.
On Monday, 4 September 2023 at 18:55:07 UTC+1 Brian Candler wrote:
> I'm afraid I have to contradict that answer (from an AI chatbot perhaps?)
>
> Go's regexp library, called re2, is documented here:
> https://github.com/google/re2/wiki/Syntax
>
> It *does* support the \w character class. See the section headed "Perl
> character classes (all ASCII-only)". Furthermore, the OP was successfully
> using \w with go 1.20.7. The problem arose with 1.21 and is something to
> do with plugin loading or initialization.
>
> On Monday, 4 September 2023 at 17:56:32 UTC+1 Google's Affiliate (Google
> Business Affiliate) wrote:
>
>> Hello, this is Jonathan, I can help you with your question about the
>> error parsing regexp in Go.
>>
>> The error you are getting is caused by the use of \w in your regular
>> expression. This is an invalid escape sequence in Go, because \w is not
>> a predefined character class
>> <https://stackoverflow.com/questions/6770898/unknown-escape-sequence-error-in-go>
>> 1
>> <https://stackoverflow.com/questions/6770898/unknown-escape-sequence-error-in-go>
>> . Go only supports the following escape sequences in regular expressions
>> <https://www.bing.com/search?form=MY0291&OCID=MY0291&q=Bing+AI&showconv=1#>
>> 2
>> <https://stackoverflow.com/questions/24836885/go-regex-error-parsing-regexp-invalid-escape-sequence-k>
>> :
>>
>> - \t for tab
>> - \n for newline
>> - \r for carriage return
>> - \f for form feed
>> - \a for alert
>> - \b for word boundary
>> - \B for non-word boundary
>> - \d for decimal digit
>> - \D for non-decimal digit
>> - \s for whitespace character
>> - \S for non-whitespace character
>> - \w for word character (alphanumeric plus _)
>> - \W for non-word character
>>
>> To match a word character in Go, you need to use [[:word:]], which is
>> equivalent to [0-9A-Za-z_]. Alternatively, you can use [[:alnum:]]_,
>> which is equivalent to [0-9A-Za-z]_. So, your regular expression should
>> be:
>>
>> regexp.Compile(`^([[:word:]./]+)/((?:[[:word:]]+)|[*])(.+)?$`)
>>
>> or
>>
>> regexp.Compile(`^([[:alnum:]_./]+)/((?:[[:alnum:]_]+)|[*])(.+)?$`)
>>
>> This should fix the error and allow you to load the plugin successfully.
>>
>> I hope this helps you with your problem. If you have any further
>> questions, please feel free to ask. 😊
>>
>>
>>
>> On Sunday, September 3, 2023 at 4:47:39 AM UTC-4 Olivier Szika wrote:
>>
>>> Hi,
>>>
>>> Unexpectedly, unicode.Categories is an empty map when it's only used
>>> with a plugin.
>>> I opened a ticket: https://github.com/golang/go/issues/62430
>>>
>>> Regards,
>>>
>>> Le samedi 12 août 2023 à 18:13:31 UTC+2, Wojciech S. Czarnecki a écrit :
>>>
>>>> Dnia 2023-08-08, o godz. 18:11:56
>>>> Bernd Fix <b...@hoi-polloi.org> napisał(a):
>>>>
>>>> > After switching from go1.20.7 to go1.21.0 one of my applications
>>>> > compiles without warnings or errors, but fails at run-time with the
>>>> > following panic when loading a plugin:
>>>>
>>>> IIRC release notes tools now are version aware, so likely you need to
>>>> bring
>>>> all go.mod's version to state 1.21.0
>>>>
>>>> hope this helps,
>>>>
>>>> > Cheers, Bernd.
>>>> >
>>>>
>>>>
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