RFR: 8339769: Incorrect error message during startup if working directory does not exist [v2]

[Justin Lu]

On Thu, 12 Sep 2024 23:11:31 GMT, Justin Lu <jlu at openjdk.org> wrote:

>> Please review this PR which restores the correct exception message when the current working directory can not be found during java startup in `initPhase1`.
>> 
>> Both MacOS and Linux are expected to fail with `java.lang.Error: Properties init: Could not determine current working directory` if the _user.dir_ system property cannot be initialized. Currently, MacOS now fails with `java.lang.InternalError: platform encoding not initialized` and Linux fails with  `java.lang.InternalError: null property: user.dir` which are both unexpected messages. 
>> 
>> In `System.c`, `Java_jdk_internal_util_SystemProps_00024Raw_platformProperties` calls `GetJavaProperties(JNIEnv *env)` which throws an internal error (with an appropriate message) for Unix platforms when the current working directory cannot be found. However, this exception is never checked and thus unexpected failures occur later. NULL should be returned after the exception is thrown, so that the initialization fails with the expected error when the return value is checked.
>> 
>> 
>>     // Get the platform specific values
>>     sprops = GetJavaProperties(env);
>>     CHECK_NULL_RETURN(sprops, NULL);
>> 
>> 
>> Testing done locally on both platforms.
>
> Justin Lu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   return null in exception site instead

> Curiously in the Windows implementation of `GetJavaProperties(...)` in `java_props_md.c` in case of a failure to get the current working directory, we seem to just skip setting the working directory and don't raise any error:
> 
> ```c
> /* Current directory */
> {
>     WCHAR buf[MAX_PATH];
>     if (GetCurrentDirectoryW(sizeof(buf)/sizeof(WCHAR), buf) != 0)
>         sprops.user_dir = _wcsdup(buf);
> }
> ```

Hi Jai,

I noticed that too. I tried to replicate this scenario on Windows and was always prevented from deleting the directory that I was currently in: _The process cannot access the file because it is being used by another process._

But I'm sure there are ways to get the working directory deleted that I am unaware of. To make this fix more complete, I can add similar behavior where an exception is thrown for Windows if `GetCurrentDirectoryW` fails. AFAICT this would be correcting a faulty error message with a proper one, and so there is no behavioral change. What do you think?

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PR Comment: https://git.openjdk.org/jdk/pull/20975#issuecomment-2349354516