1> Range arithmetics and assertions

[orklah]

This PR is the continuation of #6210. It should fix some issues introduced in it due to assertions.

However, I underestimated this task. There are a few points I don't know how to fix and I'll probably need help for that.

If we need to make a new release, I think #6210 should be reverted to prevent creating false positives in builds. I'll reintegrate in this PR later

EDIT:
this fixes #5635
this fixes #4972
this fixes #6488
this fixes #6467

[weirdan]

I'm planning to cut a new release this weekend. Do you reckon I'll need to revert #6210 ?

[orklah]

Yes, please do. I tried to work on this since then and I have obstacles everywhere. Better do it now...

[orklah]

I put aside loop features for now, they're pretty complex and they're not required for now.

I also put aside the TPositiveInt deprecation, this PR should have less impact now because I kept TPositiveInt first for now when applicable.

This PR should be ok, except for a test here:

psalm/tests/TypeReconciliation/ConditionalTest.php

Line 2737 in 3ad3375

'dontEraseNullAfterGreaterThanCheck' => [

I don't understand why null should be preserved through the conditional given it's always false: https://3v4l.org/K2Ed1

The next step will be to remove TPositiveInt from assertions while still keeping everythink working.

[orklah]

Note: please merge #6306 before this.

[weirdan]

I don't understand why null should be preserved through the conditional given it's always false

That doesn't make sense for me either, not with 0 anyway.

[orklah]

@weirdan can we maybe do a new release and merge this after?

[weirdan]

@orklah sure, will do this weekend.

[orklah]

the CI is currently failing on phpunit.

this is due to a particular construction like this:

function scope(int $a) {
    const A = array('a', 'b');

    $result = A[$i % count(A)];
}

Before this PR, Psalm was infering $i % count(A) to int. Now that the inference has improved, it's infered to int<-1, 1>, because we know the count(A) will return 2.

However, in Psalm A[$b] is tolerated when $b is a positive-int or an int, but it's not when $b is an integer range (this is deliberate as it's one of the way integer range can find new bugs).

The issue in phpunit can be fixed by adding phpdoc to $i that it's a positive-int, this way Psalm will infer the modulo result as int<0, 1> and it will be compatible with expected array-keys 0|1.

I think we can merge this now

[orklah]

I tried to document as much as I could directly in the code, but I'll make a summary here of what the reason for each modified file is for review and future reference purposes:

• AssertionFinder.php: I introduced two big new assertions: >X and <X to infer ranges. They replaced incomplete previous assertions like hasPositiveNumberCheck and hasZeroCheck.
• NonDivArithmeticOpAnalyzer.php: I allowed Psalm to make literal arithmetic operations between two integer range and between integer range and other int (this is what improved the modulo operation I was talking about above)
• IntegerRangeComparator.php: this is an object dedicated to check if an Integer range can be contained by other types. Either in another IntegerRange or even in a bunch of other integer types combined. This is quite a new notion in Psalm to use multiple types to satisfy one
• ScalarTypeComparator.php: this checks whether another integer type can be contained by an integer range
• UnionTypeComparator.php: this one is the step before the two above files. One piece of code is designed to call IntegerRangeComparator to handle the multiple ints that can contain an integer range. The other is a special case needed because until now, Psalm considered two types as "contained by" when their atomics could be identical, but this is not exactly true anymore with integer range (see comment for more info)
• SimpleAssertionReconciler.php: it is the file that process what we found in AssertionFinder. It takes the known type for a variable and will try to apply new assertions. I commented some piece of code related to loops because it's a very complex topic we'll have to come back to after this one is merged. Also there are some places where we could emit issues that I intend to add in another PR
• TypeCombiner.php: this is the file that is used to make multiple types into one. It remove redundancies and expand existing types instead of just putting them altogether
• TIntRange.php: I added some useful functions to recalculate bounds or to check if an integer is contained in the range
• Union.php: hasInt is now true if there is range in the union, isAlwaysTruthy can be true for an IntegerRange(I decommented a piece of code I introduced in a previous PR) and I added a useful function to fetch all ranges

[weirdan]

LGTM. @orklah, feel free to merge.

[weirdan]

Congrats on your first merge! 🎆

[orklah]

Thanks! 🥳