RFR: JDK-8171859: Configure check for modular boot jdk needs to be updated

[Erik Joelsson]

Hello,

Thanks for the suggestions. The way the test is currently implemented is 
using a framework for finding valid JVM parameters. It basically runs:

java $ArgToTest -version

and parses the output for warnings and verifies that the version was 
printed. After looking at this more closely, I realize the 
--patch-module option was chosen to fit this kind of test. On the other 
hand, we could easily change the implementation here to just run "java 
--list-modules > /devnull" and check the return code. That's probably 
cleaner anyway.

/Erik

On 2016-12-22 17:33, Mandy Chung wrote:
> Using —-patch-module is one option.
>
> Alternatively, you can use other new options such as:
>    $ java --dry-run -m jdk.compiler/com.sun.tools.javac.Main
>
> This stops before invoking the main method.
>
> or
>    $ java —-list-modules
>
> This lists the observable modules in the image.
>
> Mandy
>
>> On Dec 22, 2016, at 1:39 AM, Erik Joelsson <erik.joelsson at oracle.com> wrote:
>>
>> Hello,
>>
>> Configure has a check to see if the boot jdk is module aware/enabled. Like many others, the build needs to adapt its behavior when using such a boot jdk. The current check is no longer compatible with the latest JDK 9 builds:
>>
>> java -version --patch-module foo=bar
>> WARNING: Unknown module: foo specified in --patch-module
>>
>> I propose a simple adjustment, to instead specify java.base as the module to patch. I also made it explicit that the directory to patch from does not exist.
>>
>> I'm open to suggestions on better tests though, but would prefer if they can be as simple as checking for a command line argument.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8171859
>>
>> Patch:
>>
>> diff -r 84c58139cbd3 common/autoconf/boot-jdk.m4
>> --- a/common/autoconf/boot-jdk.m4
>> +++ b/common/autoconf/boot-jdk.m4
>> @@ -305,7 +305,9 @@
>>    BOOT_JDK_SOURCETARGET="-source 8 -target 8"
>>    AC_SUBST(BOOT_JDK_SOURCETARGET)
>>
>> -  ADD_JVM_ARG_IF_OK([--patch-module foo=bar], dummy, [$JAVA])
>> +  # Use a non existing directory as the directory will be scanned otherwise
>> +  # and can potentially take a lot of time.
>> +  ADD_JVM_ARG_IF_OK([--patch-module java.base=SOME_DIR_THAT_DOES_NOT_EXIST], dummy, [$JAVA])
>>    AC_MSG_CHECKING([if Boot JDK supports modules])
>>    if test "x$JVM_ARG_OK" = "xtrue"; then
>>      AC_MSG_RESULT([yes])
>>
>>
>> /Erik
>>