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Niclas van Eyk 5f019cef53
Initial proposal for psalm-require-{extends, implements} (#4361) 
* initial implementation of psalm-require-extends

* Added @psalm-require-implements

* Added shortcode for ExtensionRequirementViolation

* Docs & cofig entries for @pasalm-require-{implements,extends}

* Added requirement violations to issues.md
2021-01-29 11:41:10 +01:00
..
annotating_code add documentation for pure-callable (#4329) 2021-01-29 11:39:55 +01:00
manipulating_code Add more accurate description of functionality 2021-01-29 11:39:44 +01:00
running_psalm Initial proposal for psalm-require-{extends, implements} (#4361) 2021-01-29 11:41:10 +01:00
security_analysis Fix minor typos in docs (#3956) 2020-08-08 08:09:41 -04:00
how_psalm_works.md Fix minor typos in docs (#3956) 2020-08-08 08:09:41 -04:00
README.md 4.x (#4363) 2021-01-29 11:39:58 +01:00
what_makes_psalm_complicated.md stripping trailing whitespace 2019-02-11 18:39:19 -05:00

README.md

About Psalm

Psalm is a static analysis tool that attempts to dig into your program and find as many type-related bugs as possible.

It has a few features that go further than other similar tools:

  • Mixed type warnings
    If Psalm cannot infer a type for an expression then it uses a mixed placeholder type. mixed types can sometimes mask bugs, so keeping track of them helps you avoid a number of common pitfalls.

  • Intelligent logic checks
    Psalm keeps track of logical assertions made about your code, so if ($a && $a) {} and if ($a && !$a) {} are both treated as issues. Psalm also keeps track of logical assertions made in prior code paths, preventing issues like if ($a) {} elseif ($a) {}.

  • Property initialisation checks
    Psalm checks that all properties of a given object have values after the constructor is called.

Psalm also has a few features to make it perform as well as possible on large codebases:

  • Multi-threaded mode
    Wherever possible Psalm will run its analysis in parallel to save time. Useful for large codebases, it has a massive impact on performance.

  • Incremental checks
    By default Psalm only analyses files that have changed and files that reference those changed files.

Example output

Given a file implode_strings.php:

<?php
$a = ['foo', 'bar'];
echo implode($a, ' ');

> ./vendor/bin/psalm implode_strings.php
ERROR: InvalidArgument - somefile.php:3:14 - Argument 1 of implode expects `string`, `array` provided (see https://psalm.dev/004)

Inspirations

There are two main inspirations for Psalm:

  • Etsy's Phan, which uses nikic's php-ast extension to create an abstract syntax tree
  • Facebook's Hack, a PHP-like language that supports many advanced typing features natively, so docblocks aren't necessary.

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