Improve range multiplication and division #1961

VincentLanglet · 2022-11-04T02:32:22Z

Fix https://phpstan.org/r/8415cbf3-71d2-4f26-8e01-718cac6fb019

VincentLanglet · 2022-11-04T02:35:09Z

src/Reflection/InitializerExprTypeResolver.php

-			if ($operand instanceof ConstantIntegerType) {
-				/** @var int|float|null $min */
-				$min = $rangeMin !== null ? $rangeMin * $operand->getValue() : null;
+			$min1 = ($rangeMin ?? -INF) * ($operandMin ?? -INF);


Multiplication was wrong for thing like

int<-1, 2> * int<-1, 2>

we shouldn't always multiply both min and both max.
Sometimes it's one min multiplied by the other max.

Multiplication and using min/max function wasn't easy with the null value. The easiest solution I found is to use -INF and INF instead of null.

VincentLanglet · 2022-11-04T02:37:32Z

src/Reflection/InitializerExprTypeResolver.php

+				$operandMin = $operandMin !== 0 ? $operandMin : 1;
+				$operandMax = $operandMax !== 0 ? $operandMax : -1;
+
+				if (


I found really complicated to compute

int<-1, 2> / int<-1, 2>

It seemed easier to split negative and positive integers.

So

int<-1, 0> / int<-1, 0> int<-1, 0> / int<0, 2> int<0, 2> / int<-1, 0> int<0, 2> / int<0, 2>

And then I merge all these types.

VincentLanglet · 2022-11-04T02:39:49Z

src/Reflection/InitializerExprTypeResolver.php

+					if ($result->equals(new UnionType([new IntegerType(), new FloatType()]))) {
+						return new BenevolentUnionType([new IntegerType(), new FloatType()]);
+					} else {
+						return $result;
+					}


If I merge float|int<min, 0> and float|int<0, max> seems like before we wanted (float|int) to reproduce the behavior of division by an int.

That's why we had

if ($min === null && $max === null) { return new BenevolentUnionType([new IntegerType(), new FloatType()]); }

So I tried to reproduce the same behavior.

VincentLanglet · 2022-11-04T02:43:00Z

src/Reflection/InitializerExprTypeResolver.php

+				$min1 = $operandMin !== null ? ($rangeMin ?? -INF) / $operandMin : $rangeMinSign * -0.1;
+				$min2 = $operandMax !== null ? ($rangeMin ?? -INF) / $operandMax : $rangeMinSign * 0.1;
+				$max1 = $operandMin !== null ? ($rangeMax ?? INF) / $operandMin : $rangeMaxSign * -0.1;
+				$max2 = $operandMax !== null ? ($rangeMax ?? INF) / $operandMax : $rangeMaxSign * 0.1;


I basically use the same tips than for multiplication, replacing null by INF. But a division by INF is not great, giving the float 0 or NAN.

I can still simulate this division by saying the min/max is really near from 0 with the correct sign.

VincentLanglet · 2022-11-04T02:44:34Z

src/Reflection/InitializerExprTypeResolver.php

 			if ($operand instanceof IntegerRangeType
-				&& ($operand->getMin() === null || $operand->getMax() === null)


The float type must be added as soon as I divide by a Range. For instance

int<-1, 2> / int<-1, 2>

There is 1 / 2 which is a float, even if both min and max are int.

Strictly speaking, this is not always true.
like

6 / int<1,3>

but I think it would get too complicated adding this logic in this PR, so no need to fix it now. It's not working correctly now anyway:)

Yeah, I agree. I didn't find a better solution.
Should still be better than https://phpstan.org/r/e2efef83-28d5-4c57-83c6-c8be5fb4d67d

Moreover 6 / int<1, 6> is possibly a float.
So the only improvement could be to check every possible values unless we find a float...
This seems to complicated.

In the same way 6 / int<1,3> is int<2, 6> but the values 4 and 5 are not possible.
But again, unless testing all the values...

Yeah, your solution is smart and the results are much better than before!
The number of edge cases are small because it only happens if
range multiple (like 1 * 2 * 3) * k === constant integer (like 6)

VincentLanglet · 2022-11-04T02:45:52Z

src/Reflection/InitializerExprTypeResolver.php

 			) {
 				if (is_float($min)) {
-					$min = (int) $min;
+					$min = (int) ceil($min);


(int) 0.5 was 0.

So, int<1, 2> / 2 was int<0, 1>|float which is wrong, 0 was never possible.

(int) ceil(0.5) is 1.
And 1|float is the correct result.

VincentLanglet · 2022-11-04T02:47:55Z

tests/PHPStan/Analyser/data/integer-range-types.php

@@ -218,70 +218,70 @@ public function math($i, $j, $z, $pi, $r1, $r2, $r3, $rMin, $rMax, $x, $y) {
 		assertType('int<2, 13>', $r1 + $j);
 		assertType('int<-2, 9>', $r1 - $j);
 		assertType('int<1, 30>', $r1 * $j);
-		assertType('float|int<0, 10>', $r1 / $j);
+		assertType('float|int<1, 10>', $r1 / $j);


0 was never possible

Please verify each expectation change on wolfram alpha like
https://www.wolframalpha.com/input?i=%28interval%5B1%2C10%5D+%2F+interval%5B1%2C3%5D%29

@staabm I checked every expectation, and I'm good with my results.
I added some link in the review, but wolfram alpha is sometimes wrong.

See https://www.wolframalpha.com/input?i=%28-1%2Finterval%5B-9999%2C+5%5D+%29
or https://www.wolframalpha.com/input?i=%28interval%5B1%2C10%5D+%2F+interval%5B-9999%2C5%5D%29

This is especially why in the code I split the / computation to not have together the positive and the negative int.

VincentLanglet · 2022-11-04T02:47:59Z

tests/PHPStan/Analyser/data/integer-range-types.php

 		assertType('int<min, 15>', $rMin * $j);
 		assertType('int<5, max>', $rMax * $j);

 		assertType('int<2, 13>', $j + $r1);
 		assertType('int<-9, 2>', $j - $r1);
 		assertType('int<1, 30>', $j * $r1);
-		assertType('float|int<0, 3>', $j / $r1);
+		assertType('float|int<1, 3>', $j / $r1);


0 was never possible

https://www.wolframalpha.com/input?i=%28interval%5B1%2C3%5D+%2F+interval%5B1%2C10%5D%29

VincentLanglet · 2022-11-04T02:48:03Z

tests/PHPStan/Analyser/data/integer-range-types.php

 		assertType('int<min, 15>', $j * $rMin);
 		assertType('int<5, max>', $j * $rMax);

 		assertType('int<-19, -10>|int<2, 13>', $r1 + $z);
 		assertType('int<-2, 9>|int<21, 30>', $r1 - $z);
 		assertType('int<-200, -20>|int<1, 30>', $r1 * $z);
-		assertType('float|int<0, 10>', $r1 / $z);
+		assertType('float|int<1, 10>', $r1 / $z);


0 was never possible

VincentLanglet · 2022-11-04T02:48:07Z

tests/PHPStan/Analyser/data/integer-range-types.php

 		assertType('int', $rMin * $z);
 		assertType('int<min, -100>|int<5, max>', $rMax * $z);

 		assertType('int<2, max>', $pi + 1);
 		assertType('int<-1, max>', $pi - 2);
 		assertType('int<2, max>', $pi * 2);
-		assertType('float|int<0, max>', $pi / 2);
+		assertType('float|int<1, max>', $pi / 2);


0 was never possible

https://www.wolframalpha.com/input?i=%28interval%5B1%2C99999%5D+%2F+2%29

VincentLanglet · 2022-11-04T02:48:59Z

tests/PHPStan/Analyser/data/integer-range-types.php

 		assertType('int<2, max>', 1 + $pi);
 		assertType('int<min, 2>', 2 - $pi);
 		assertType('int<2, max>', 2 * $pi);
-		assertType('float|int<2, max>', 2 / $pi);
+		assertType('float|int<1, 2>', 2 / $pi);


$pi is a positive int so the result cannot be an int bigger than 2

https://www.wolframalpha.com/input?i=%282+%2F+interval%5B1%2C99999%5D%29

VincentLanglet · 2022-11-04T02:52:03Z

tests/PHPStan/Analyser/data/integer-range-types.php


 		assertType('int<6, max>', $r1 + $rMax);
 		assertType('int', $r1 - $rMax);
 		assertType('int<5, max>', $r1 * $rMax);
-		assertType('float|int<0, max>', $r1 / $rMax);
+		assertType('float|int<1, 2>', $r1 / $rMax);


int<1, 10> / int<5, max>

https://www.wolframalpha.com/input?i=%28interval%5B1%2C10%5D+%2F+interval%5B5%2C+9999%5D%29

VincentLanglet · 2022-11-04T02:52:30Z

tests/PHPStan/Analyser/data/integer-range-types.php

 		assertType('int<6, max>', $rMax + $r1);
 		assertType('int<-5, max>', $rMax - $r1);
 		assertType('int<5, max>', $rMax * $r1);
-		assertType('float|int<5, max>', $rMax / $r1);
+		assertType('float|int<1, max>', $rMax / $r1);


int<5, max> / int<1, 10>

When you do 5 / 5 you get 1.

https://www.wolframalpha.com/input?i=%28interval%5B5%2C+9999%5D%2Finterval%5B1%2C10%5D+%29

VincentLanglet · 2022-11-04T02:52:38Z

tests/PHPStan/Analyser/data/integer-range-types.php


 		assertType('5|10|15|20|30', $x / $y);

-		assertType('float|int<0, max>', $rMax / $rMax);
+		assertType('float|int<1, max>', $rMax / $rMax);


0 was never possible

https://www.wolframalpha.com/input?i=%28interval%5B5%2C+9999%5D%2Finterval%5B5%2C+9999%5D+%29

VincentLanglet · 2022-11-04T02:53:20Z

tests/PHPStan/Analyser/data/integer-range-types.php

@@ -307,8 +307,8 @@ public function maximaInversion($rMin, $rMax) {
 		assertType('int<-5, max>', $rMin * -1);
 		assertType('int<min, -10>', $rMax * -2);

-		assertType('float|int<0, max>', -1 / $rMin);
-		assertType('float|int<min, 0>', -2 / $rMax);
+		assertType('-1|1|float', -1 / $rMin);


-1 / $rMin with $rMin an int will never be something else

Wolframalpha is not doing great on this https://www.wolframalpha.com/input?i=%28-1%2Finterval%5B-9999%2C+5%5D+%29

VincentLanglet · 2022-11-04T02:53:50Z

tests/PHPStan/Analyser/data/integer-range-types.php

-		assertType('float|int<0, max>', -1 / $rMin);
-		assertType('float|int<min, 0>', -2 / $rMax);
+		assertType('-1|1|float', -1 / $rMin);
+		assertType('float', -2 / $rMax);


$rMax is int<5, max> so it's not possible to have an int

https://www.wolframalpha.com/input?i=%28-2%2Finterval%5B5%2C+9999%5D+%29

phpstan-bot · 2022-11-04T03:08:49Z

This pull request has been marked as ready for review.

staabm · 2022-11-04T08:40:08Z

tests/PHPStan/Analyser/data/integer-range-types.php

+		assertType('0', 0 * $positive);
+		assertType('int<0, max>', $positive * $positive);
+		assertType('0', 0 * $negative);
+		assertType('int<0, max>', $negative * $negative);


another assert for $negative * $positve?

Sure, added assertType('int<min, 0>', $negative * $positive);

VincentLanglet · 2023-01-02T22:52:18Z

I rebased and got all the test green if you find time this is Ready to be review @ondrejmirtes

ondrejmirtes · 2023-01-08T14:53:58Z

Thank you.

VincentLanglet commented Nov 4, 2022

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VincentLanglet force-pushed the improveRangeComputation branch from d3e52c7 to d9e2654 Compare November 4, 2022 02:47

VincentLanglet commented Nov 4, 2022

View reviewed changes

VincentLanglet changed the title ~~Improve range computation~~ Improve range multiplication and division Nov 4, 2022

VincentLanglet marked this pull request as ready for review November 4, 2022 03:08

VincentLanglet requested a review from staabm November 4, 2022 08:28

staabm reviewed Nov 4, 2022

View reviewed changes

VincentLanglet force-pushed the improveRangeComputation branch from 3a5c041 to b3081b4 Compare November 6, 2022 11:20

VincentLanglet requested a review from staabm November 16, 2022 11:22

VincentLanglet force-pushed the improveRangeComputation branch from 430a590 to 6b93857 Compare November 19, 2022 12:28

VincentLanglet added 5 commits January 2, 2023 23:02

Improve range computation

98afed6

Fix tests

de033df

Avoid issue with multiplication by 0

228217e

Add test

0d875e6

Fix cs

bab5bf0

VincentLanglet force-pushed the improveRangeComputation branch from 6b93857 to bab5bf0 Compare January 2, 2023 22:02

ondrejmirtes force-pushed the 1.9.x branch from a5d90c1 to a69c7f0 Compare January 5, 2023 14:23

ondrejmirtes merged commit 35e4813 into phpstan:1.9.x Jan 8, 2023

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Improve range multiplication and division #1961

Improve range multiplication and division #1961

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ondrejmirtes commented Jan 8, 2023

		if ($operand instanceof IntegerRangeType
		&& ($operand->getMin() === null \|\| $operand->getMax() === null)

Improve range multiplication and division #1961

Improve range multiplication and division #1961

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VincentLanglet commented Nov 4, 2022 • edited

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VincentLanglet commented Jan 2, 2023

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VincentLanglet commented Nov 4, 2022 •

edited

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