RFR: 8266396: Save VSCMD_DEBUG output in Windows build [v3]

[John Neffenger]

On Tue, 11 May 2021 01:17:32 GMT, John Neffenger <jgneff at openjdk.org> wrote:

>> The Windows build calls a series of batch files to get the Visual Studio paths and environment variables. The batch files are a black box: any messages they print are discarded. If anything goes wrong, the only signs are a vague Gradle exception and a corrupted properties file.
>> 
>> This has been causing problems for years. There are at least 49 messages on the mailing since 2017 that discuss the exception and ways to work around it.
>> 
>> This pull request lets you enable the batch file messages, shedding light on their internal workings and allowing you to catch any errors at their source. Specifically, it adds the variable `VSCMD_DEBUG` to the environment of `genVSproperties.bat` and documents its use.
>> 
>> ### Before
>> 
>> For example, if your `PATH` environment variable is missing `C:/Windows/System32`, like mine was, you'll see the following errors:
>> 
>> 
>> $ gradle sdk
>> Dependency verification is an incubating feature.
>> 
>> FAILURE: Build failed with an exception.
>> 
>> * Where:
>> Script 'C:\cygwin64\home\john\src\jfx\buildSrc\win.gradle' line: 108
>> 
>> * What went wrong:
>> A problem occurred evaluating script.
>>> FAIL: WINSDK_DIR not defined
>> 
>>     ︙
>> 
>> BUILD FAILED in 4s
>> 
>> 
>> *Me:* What's a `WINSDK_DIR`? The Wiki says, "This means that you will have to define these paths manually." I guess this is normal. 😕️
>> 
>> ### After
>> 
>> With this change, you can set the debug level to "3" in the `win.gradle` file and get a better picture of the problem:
>> 
>> 
>> $ gradle sdk
>> Dependency verification is an incubating feature.
>> 
>>> Configure project :
>> 'reg' is not recognized as an internal or external command,
>> operable program or batch file.
>> 'reg' is not recognized as an internal or external command,
>> operable program or batch file.
>> 'reg' is not recognized as an internal or external command,
>> operable program or batch file.
>> 
>>     ︙
>> 
>> 'powershell.exe' is not recognized as an internal or external command,
>> operable program or batch file.
>> 
>> FAILURE: Build failed with an exception.
>> 
>> * Where:
>> Script 'C:\cygwin64\home\john\src\jfx\buildSrc\win.gradle' line: 108
>> 
>> * What went wrong:
>> A problem occurred evaluating script.
>>> FAIL: WINSDK_DIR not defined
>> 
>>     ︙
>> 
>> BUILD FAILED in 3s
>> 
>> 
>> *Me:* Oh, it's just a "command not found" error. I'll check my `PATH`. 🤓
>
> John Neffenger has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Skip sending telemetry to fix "file in use" error

My previous comment is confusing no matter how many times I edit it. 😕 Let me try again.

> I would like to give this PR a bump.

Actually, I was planning to close it. One of my goals was to document how to find the true source of the WINSDK_DIR error, and that seems to have worked (see above). It's also very easy to find this pull request by searching the repository for the error message. That visibility might be even better than the fix. Unless you want to take it over, I'll close it later this month.

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PR: https://git.openjdk.org/jfx/pull/488