RFR: 8233725: ProcessTools.startProcess() has output issues when using an OutputAnalyzer at the same time [v2]

[Chris Plummer]

On Thu, 20 Apr 2023 18:40:52 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> ProcessTools.startProcess() creates process and read it's output error streams. So the any other using of corresponding Process.getInputStream() and Process.getErrorStream() doesn't get process streams.
>> 
>> This fix preserve process streams content and allow to read it after process completion. The another possible solution would be to throw exception when user tries to read already drained streams to fail tests earlier. However it complicates usage of ProcessTools.startProcess() methods.
>> 
>> The regression test has been provided with issue.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JStackStressTest.java updated.

test/jdk/sun/tools/jhsdb/JStackStressTest.java line 86:

> 84:             } catch (InterruptedException e) {
> 85:             }
> 86:             OutputAnalyzer jshellOutput = new OutputAnalyzer(jShellProcess);

It's not clear to me how moving this is fixing anything.

test/jdk/sun/tools/jstatd/JstatdTest.java line 357:

> 355:         assertEquals(stdout.size(), 1, "Output should contain one line");
> 356:         assertTrue(stdout.get(0).startsWith("jstatd started"), "List should start with 'jstatd started'");
> 357:         assertNotEquals(output.getExitValue(), 0,

Before your fix, was the "jstatd started" line being missed because of this bug.

test/lib/jdk/test/lib/process/ProcessTools.java line 750:

> 748:         public InputStream getInputStream() {
> 749:             try {
> 750:                 waitFor();

With this added `waitFor()` the assumption now is that the caller doesn't intent to do incremental reads of the output as the process generates it. For example, if the test were to send some command to the process and then want to read the resulting output, and do this repeatedly, it won't able to use the InputStream to do that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13560#discussion_r1173141642
PR Review Comment: https://git.openjdk.org/jdk/pull/13560#discussion_r1173139688
PR Review Comment: https://git.openjdk.org/jdk/pull/13560#discussion_r1173146951