[PATCH] D53215: [libcxx] Improve reporting when running the lit test suite

[Louis Dionne via Phabricator]

ldionne added a comment.

In https://reviews.llvm.org/D53215#1264337, @EricWF wrote:

> Could you elaborate as to why this is needed/beneficial? Most of the information this patch adds to reports is already displayed to the user during the initial configuration.


This is useful whenever you try to see why a test is passing when you think it should fail. In my case, I was trying to figure out what was different between two `lit` invocations: a test was failing on a CI but it was passing on my local machine (i.e. I couldn't reproduce the failure). I tried adding `-a` thinking "this is going to tell me all I need to know", but it didn't. So instead I had to make the test fail artificially, look at what the command-line was (because that is printed when the test fails), and try to reproduce that way. Much better would be to just run the test under `-a`, which is advertised by `lit` as dumping everything.

There is some amount of crap in what's printed, e.g. temporary executable files, etc. These can be edited manually when working on a reproduction. Also note that you should not normally use `-a` when running `lit` (and I don't think people usually do that). You use `-a` when you really want to see what's going on, and this patch gives you that information.


Repository:
  rCXX libc++

https://reviews.llvm.org/D53215