RFR: 8343802: Prevent NULL usage backsliding [v2]

[Chen Liang]

On Wed, 5 Feb 2025 20:16:57 GMT, Nizar Benalla <nbenalla at openjdk.org> wrote:

>> Please review this patch to add a test that checks the hotspot sources and test files for usages of NULL.
>> It scans files in those directories, filtering out certain files as well as all `.c`, `.java` and `.jar` files in test sources. 
>> 
>> Before adding line 86 and excluding `os_windows.cpp`, the test failed with:
>> 
>> 
>> Error: 'NULL' found in /w/jdk/src/hotspot/os/windows/os_windows.cpp at line 4436:
>>     HMODULE hModule = NULL;
>> Error: 'NULL' found in /w/jdk/src/hotspot/os/windows/os_windows.cpp at line 4437:
>>     GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, NULL, &hModule);
>> java.lang.RuntimeException: Found usage of 'NULL' in source files. See errors above.
>> 	at TestNoNULL.main(TestNoNULL.java:73)
>> 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
>> 	at java.base/java.lang.reflect.Method.invoke(Method.java:565)
>> 	at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:333)
>> 	at java.base/java.lang.Thread.run(Thread.java:1447)
>
> Nizar Benalla has updated the pull request incrementally with one additional commit since the last revision:
> 
>   update based on feedback

test/hotspot/jtreg/sources/TestNoNULL.java line 56:

> 54:         }
> 55: 
> 56:         if (dir == null) {

@sormuras Do you know if the source directory (or directories) of the JDK is passed to jtreg at all? The current approach seems a bit hacky.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/23466#discussion_r1944104148