[PATCH] D154987: [lit] Implement PYTHON directive and config.prologue

Thu Oct 5 12:57:27 PDT 2023

jdenny added a comment.

In D154987#4652870 <https://reviews.llvm.org/D154987#4652870>, @awarzynski wrote:

> Sorry for delay, I tend to focus on GitHub these days.

No worries.  I'm a bit distracted at the moment anyway.

> I'm OK with this change.  Based on the feedback, this is clearly desirable by various folks. And great deal of effort has gone into preparing LIT for this PR, so I wouldn't want to block it.

Thanks for your understanding.

For people who are not interested in the PYTHON directive, I hope they will at least benefit from the debugger option that D158954 <https://reviews.llvm.org/D158954> builds on top for the sake of lit tests (whether or not those tests actually use PYTHON directives explicitly).  After all the recent discussion of copying and pasting shell code from lit's output to a terminal window and hoping that terminal's shell processes them correctly, and after my own experience trying to replicate environment variables and investigating lit substitution issues, I imagine a proper debugger that can step through RUN lines and examine/adjust state would be a welcome improvement.

In D154987#4652870 <https://reviews.llvm.org/D154987#4652870>, @awarzynski wrote:

> While I'm still concerned about extending LIT like this, there's an option for people _not to use_ the new directive.
>
> As always with this sort of changes, I suggest "advertising" on Discourse to make sure that people are aware what's coming.

As you suggested, this new feature is opt-in.  It is not meant to change behavior for existing lit tests.  For that reason, I think it's less important to write a general RFC before landing than in the case of, for example, the recent lit debug output changes.  I'm inclined to land this one first (after a technical review) and advertise afterward so that folks like @Endill can move forward.  That would also permit others to more easily try out the new feature once we do advertise.  We can always tweak things afterward as the need arises.  Is that a reasonable plan?

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D154987/new/

https://reviews.llvm.org/D154987