Add note about possibly needed memory_limit increase

[thinkspill]

No description provided.

[ondrejmirtes]

I was rather thinking about detecting this state and showing message about memory limit in the next run. It's more intuitive than putting it in the README. What do you think?

[thinkspill]

Agreed, that would be ideal.

Mentioning it in the README may be a quick fix until that happens.

[ondrejmirtes]

Solved it in c4a5846 and a few further commits.

[thinkspill]

I tried this change today, and I'm not sure it solves the issue.

When I first ran analyse and got the unexplained crash, my first instinct wasn't to run it again (which, now, would cause the OOM message to appear). Instead I Googled it and checked the Issues here, where I then learned of the OOM issue.

The issue is that there is still no up-front notice or warning about the very likely OOM crash. Only if you run it twice in an OOM situation will you then be notified. At the very least, I would mention this possibility in the docs.

As another possible solution, you could potentially warn up-front on first-run by guesstimating memory usage needs based on how many files are to be included in the scan, though this may require adding a "pre-scan scan". PHPStan is fast enough compared to phan that this wouldn't bother me much.

[ondrejmirtes]

Yep, my solution assumes the user will re-run the application after it crashes for the first time. I think it's a quite natural thing to do. If something crashes unexpectedly, my reaction is "whoa, what happened!? Let me make sure I haven't overlooked anything when the application was executed by rerunning it one more time".

I don't think there is any deterministic way to guesstimate how much memory will be consumed by pre-scanning the codebase. I don't think it's worth it to slow down PHPStan for everyone just to inform people with low memory limit about a possible crash. But I can add a note about this to the README. Thanks for the suggestions!