Untrapped Divide by Zero Error

[rivets]

I'm afraid all I have is a stack trace. I'm using PHP 8.0.1

Uncaught Exception: Division by zero
Stack trace in the forked worker:
#0FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php(181): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonDivArithmeticOpAnalyzer::analyzeNonDivOperands(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(Psalm\Codebase), Object(Psalm\Config), Object(Psalm\Context), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Type\Atomic\TLiteralInt), Object(Psalm\Type\Atomic\TLiteralInt), Array, Array, false, false, false, NULL)
#1 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonComparisonOpAnalyzer.php(121): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonDivArithmeticOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(Psalm\Internal\Provider\NodeDataProvider), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Expr\BinaryOp\Div), NULL, Object(Psalm\Context))
#2 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOpAnalyzer.php(325): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonComparisonOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context))
#3 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php(231): Psalm\Internal\Analyzer\Statements\Expression\BinaryOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), 0, true)
#4 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php(39): Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer::handleExpression(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), false, Object(Psalm\Context), true)
#5 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/StatementsAnalyzer.php(519): Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), false, Object(Psalm\Context), true)
#6 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/StatementsAnalyzer.php(168): Psalm\Internal\Analyzer\StatementsAnalyzer::analyzeStatement(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Stmt\Expression), Object(Psalm\Context), Object(Psalm\Context))
#7 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php(654): Psalm\Internal\Analyzer\StatementsAnalyzer->analyze(Array, Object(Psalm\Context), Object(Psalm\Context), true)
#8 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ClassAnalyzer.php(1968): Psalm\Internal\Analyzer\FunctionLikeAnalyzer->analyze(Object(Psalm\Context), Object(Psalm\Internal\Provider\NodeDataProvider), Object(Psalm\Context))
#9 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ClassAnalyzer.php(745): Psalm\Internal\Analyzer\ClassAnalyzer->analyzeClassMethod(Object(PhpParser\Node\Stmt\ClassMethod), Object(Psalm\Storage\ClassLikeStorage), Object(Psalm\Internal\Analyzer\ClassAnalyzer), Object(Psalm\Context), Object(Psalm\Context))
#10 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/FileAnalyzer.php(211): Psalm\Internal\Analyzer\ClassAnalyzer->analyze(Object(Psalm\Context), Object(Psalm\Context))
#11FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(340): Psalm\Internal\Analyzer\FileAnalyzer->analyze(NULL)
#12 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php(193): Psalm\Internal\Codebase\Analyzer->Psalm\Internal\Codebase{closure}(19, '/Users/nlfm/Lib...')
#13 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(406): Psalm\Internal\Fork\Pool->__construct(Array, Object(Closure), Object(Closure), Object(Closure), Object(Closure))
#14 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(269): Psalm\Internal\Codebase\Analyzer->doAnalysis(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3)
#15 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php(639): Psalm\Internal\Codebase\Analyzer->analyzeFiles(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3, false, true)
#16 FWStan/vendor/vimeo/psalm/src/psalm.php(676): Psalm\Internal\Analyzer\ProjectAnalyzer->check('/Users/nlfm/Lib...', false)
#17 FWStan/vendor/vimeo/psalm/psalm(2): require_once('/Users/nlfm/Lib...')
#18 {main} in FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php:358
Stack trace:
#0 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php(390): Psalm\Internal\Fork\Pool->readResultsFromChildren()
#1 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(473): Psalm\Internal\Fork\Pool->wait()
#2 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(269): Psalm\Internal\Codebase\Analyzer->doAnalysis(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3)
#3 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php(639): Psalm\Internal\Codebase\Analyzer->analyzeFiles(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3, false, true)
#4 FWStan/vendor/vimeo/psalm/src/psalm.php(676): Psalm\Internal\Analyzer\ProjectAnalyzer->check('/Users/nlfm/Lib...', false)
#5 FWStan/vendor/vimeo/psalm/psalm(2): require_once('/Users/nlfm/Lib...')
#6 {main}
(Psalm 4.2.1@ea9cb72143b77e7520c52fa37290bd8d8bc88fd9 crashed due to an uncaught Throwable)

[psalm-github-bot]

Hey @rivets, can you reproduce the issue on https://psalm.dev ?

[rivets]

I'm running psalm 4.4.1 and it fails

[orklah]

Can you give the stack trace for Psalm 4.4.1? The stack above seems to come from 4.2.1

[orklah]

It really seems like Psalm does the division by zero because after it found a literal division by zero in your code. Judging from the parameters, you have a ??? / 0 expression in your code

Please run psalm with the --debug-by-line option and search for that expression in the last file it outputs?

[rivets]

Sorry - I forgot I had downgraded to see if it went away :-)

Uncaught Exception: Division by zero
Stack trace in the forked worker:
#0 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php(183): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonDivArithmeticOpAnalyzer::analyzeNonDivOperands(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(Psalm\Codebase), Object(Psalm\Config), Object(Psalm\Context), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Type\Atomic\TLiteralInt), Object(Psalm\Type\Atomic\TLiteralInt), Array, Array, false, false, false, NULL)
#1 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonComparisonOpAnalyzer.php(119): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonDivArithmeticOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(Psalm\Internal\Provider\NodeDataProvider), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Scalar\LNumber), Object(PhpParser\Node\Expr\BinaryOp\Div), NULL, Object(Psalm\Context))
#2 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOpAnalyzer.php(334): Psalm\Internal\Analyzer\Statements\Expression\BinaryOp\NonComparisonOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context))
#3 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php(228): Psalm\Internal\Analyzer\Statements\Expression\BinaryOpAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), 0, true)
#4 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php(40): Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer::handleExpression(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), false, Object(Psalm\Context), true)
#5 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/StatementsAnalyzer.php(530): Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer::analyze(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Expr\BinaryOp\Div), Object(Psalm\Context), false, Object(Psalm\Context), true)
#6 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/StatementsAnalyzer.php(172): Psalm\Internal\Analyzer\StatementsAnalyzer::analyzeStatement(Object(Psalm\Internal\Analyzer\StatementsAnalyzer), Object(PhpParser\Node\Stmt\Expression), Object(Psalm\Context), Object(Psalm\Context))
#7 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php(421): Psalm\Internal\Analyzer\StatementsAnalyzer->analyze(Array, Object(Psalm\Context), Object(Psalm\Context), true)
#8 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ClassAnalyzer.php(1639): Psalm\Internal\Analyzer\FunctionLikeAnalyzer->analyze(Object(Psalm\Context), Object(Psalm\Internal\Provider\NodeDataProvider), Object(Psalm\Context))
#9 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ClassAnalyzer.php(387): Psalm\Internal\Analyzer\ClassAnalyzer->analyzeClassMethod(Object(PhpParser\Node\Stmt\ClassMethod), Object(Psalm\Storage\ClassLikeStorage), Object(Psalm\Internal\Analyzer\ClassAnalyzer), Object(Psalm\Context), Object(Psalm\Context))
#10 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/FileAnalyzer.php(213): Psalm\Internal\Analyzer\ClassAnalyzer->analyze(Object(Psalm\Context), Object(Psalm\Context))
#11 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(340): Psalm\Internal\Analyzer\FileAnalyzer->analyze(NULL)
#12 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php(193): Psalm\Internal\Codebase\Analyzer->Psalm\Internal\Codebase{closure}(19, '/Users/nlfm/Lib...')
#13 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(406): Psalm\Internal\Fork\Pool->__construct(Array, Object(Closure), Object(Closure), Object(Closure), Object(Closure))
#14 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(269): Psalm\Internal\Codebase\Analyzer->doAnalysis(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3)
#15 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php(635): Psalm\Internal\Codebase\Analyzer->analyzeFiles(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3, false, true)
#16 FWStan/vendor/vimeo/psalm/src/psalm.php(676): Psalm\Internal\Analyzer\ProjectAnalyzer->check('/Users/nlfm/Lib...', false)
#17 FWStan/vendor/vimeo/psalm/psalm(2): require_once('/Users/nlfm/Lib...')
#18 {main} in FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php:357
Stack trace:
#0 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Fork/Pool.php(389): Psalm\Internal\Fork\Pool->readResultsFromChildren()
#1 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(473): Psalm\Internal\Fork\Pool->wait()
#2 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Codebase/Analyzer.php(269): Psalm\Internal\Codebase\Analyzer->doAnalysis(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3)
#3 FWStan/vendor/vimeo/psalm/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php(635): Psalm\Internal\Codebase\Analyzer->analyzeFiles(Object(Psalm\Internal\Analyzer\ProjectAnalyzer), 3, false, true)
#4 FWStan/vendor/vimeo/psalm/src/psalm.php(676): Psalm\Internal\Analyzer\ProjectAnalyzer->check('/Users/nlfm/Lib...', false)
#5 FWStan/vendor/vimeo/psalm/psalm(2): require_once('/Users/nlfm/Lib...')
#6 {main}
(Psalm 4.4.1@9fd7a7d885b3a216cff8dec9d8c21a132f275224 crashed due to an uncaught Throwable)

[orklah]

Well, the fix is pretty simple but I have mixed feelings about this. It's way too specific to create a new Issue and if we don't, Psalm expect the returned type of the division by zero.

I tried putting the empty type but it's not very well supported by psalm (it doesn't produce errors on usage) and I don't want to return an int or a float.

I'd advise finding the expression and fixing it because it make no sense (it will always throw an error)

For reference, the issue is there:

psalm/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php

Line 329 in fdb181f

$value = $left_type_part->value / $right_type_part->value;

Psalm sees a division with literal params and does the division by itself to infer the literal result

[rivets]

I'll check the code (there is very little division) but there isn't anything that would be a literal division by 0. This didn't happen in earlier versions and I haven't (conciously) added any code using division since I changed to the latest version.

[orklah]

You should be able to find the file quickly with --debug-by-line. It's probably some code that was already there before.

[rivets]

I've added --debug-by-line but how do I identify which file is causing the error? The error output appears in different places every run. BTW the failure leaves a dead process that you have to kill every time.

[rivets]

I've found it! It's a piece of code that has always been there as it exists to test my unhandled exception handling code - so it does a division by 0. This didn't break the version of psalm I was using before so you must have added this test more recently. Is there anyway of telling psalm not to check the line? I don't want to not check the file as psalm really helps keep things in shape.

[orklah]

Well, this looks like a legitimate use case so I proposed a PR to fix the issue. Let's see what @muglug say about the way I tried to fix it.

You could maybe try to avoid having literals on both side of the divison in the meantime. I think something like

$a = 1;
$a/0;

should be ok because it's not a literal

And yeah, Psalm indeed extended its analysis to such cases in #2132