RFR: 8352489: Relax jspawnhelper version checks to informative

[Aleksey Shipilev]

On Thu, 20 Mar 2025 11:00:01 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> src/java.base/unix/native/jspawnhelper/jspawnhelper.c line 160:
>> 
>>> 158: 
>>> 159:     if (strcmp(argv[1], VERSION_STRING) != 0) {
>>> 160:         fprintf(stdout, "Incorrect Java version: %s\n", argv[1]);
>> 
>> Don't you want to keep the comparison and print the warning if the versions don't match?
>> 
>> 
>> if (strcmp(argv[1], VERSION_STRING) != 0) {
>>     fprintf(stdout, "Warning: Version mismatch: %s != %s\n", argv[1], VERSION_STRING);
>> }
>
> I understand this mismatch is otherwise only printed in `shutItDown`

I was not able to convince myself that printing into `stdout` from jspawnhelper -- when we are not failing -- does not introduce more problems. E.g. if some pipe would be blocked or something wacky like that. So in the interest of extra safety, I only did the version printing from the diagnostic paths where we already print.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24127#discussion_r2005341889