On Fri, 11 Dec 2020 21:47:33 GMT, Patricio Chilano Mateo <pchilanom...@openjdk.org> wrote:
>>> Pumpers created by ProcessTools.startProcess() log the process >>> stdout/stderr. >>> It's quite useful for failure analysis. >> >> This was the type of thing I was hinting at when I asked if there were any >> possible negative side affects to the change. Sorry I didn't see your post >> before asking my question. > > Hi Alex, > >> Pumpers created by ProcessTools.startProcess() log the process stdout/stderr. >> It's quite useful for failure analysis. > But we are still printing the stdout and stderr of the jcmd with the log > statement in runJCmd(). Hi Chris, > From what I can tell (after a bit of possibly inaccurate grepping) this is > the only test that uses `PrcoessTools.startProcess()` in combination with > `out.stderrShouldBeEmtpyIgnoreWarnings()`, so I assume this issue of split > stderr output is unique to this test. However, it seems like that could > easily be stumbled into again, and I pity anyone who has to debug this again > (and commend you and getting to the root of the issue). > I also did a search and the other serviceability tests I found using stderrShouldBeEmtpyIgnoreWarnings() execute the process with ProcessBuilder::start(). > I have to admit I don't understanding all the ramifications of moving from > `ProcessTools.startProcess()` to just calling `pb.Start()`. Clearly > `startProcess()` has some value add. Does not using it affect the test in any > negative way? > Looking at ProcessTools.startProcess(), it just calls ProcessBuilder::start() and then executes all the other StreamPumper logic. > It's also not clear to me what the guidelines are for avoiding this issue in > the future. Is it that `startProcess()` + `OutputAnalyzer` on the same > process is forbidden, or at least forbidden if the `OutputAnalyzer` is used > for anything more than checking the exit value? > Right. Otherwise we have a race and the output of the launched process will be split between the two StreamPumpers in an unpredictable way. ------------- PR: https://git.openjdk.java.net/jdk/pull/1749
