Add psalm

[vv12131415]

Description
since there is phpstan used in this repo. I would like to suggest to use psalm.
It also has baseline like phpstan

[Tobion]

What's the point of using psalm and phpstan or psalm over phpstan?

[vv12131415]

psalm over phpstan
No, it's psalm AND phpstan

It will add more types (type inference) to the code.

[Tobion]

@vladyslavstartsev can you give some concrete examples where this would help?
See also phpstan/phpstan#2223

[vv12131415]

okey, I've finally got some time to explain
let's see what phpstan is telling us about AppendStream

                -
                        message: "#^Property GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:\\$seekable has no typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Property GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:\\$current has no typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Property GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:\\$pos has no typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Method GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:addStream\\(\\) has no return typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Method GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:detach\\(\\) should return resource\\|null but return statement is missing\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Method GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:rewind\\(\\) has no return typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

                -
                        message: "#^Method GuzzleHttp\\\\Psr7\\\\AppendStream\\:\\:seek\\(\\) has no return typehint specified\\.$#"
                        count: 1
                        path: src/AppendStream.php

when we run the same analysis in psalm, here is our output

ERROR: MissingPropertyType - src/AppendStream.php:19:13 - Property GuzzleHttp\Psr7\AppendStream::$seekable does not have a declared type - consider bool (see https://psalm.dev/045)
    private $seekable = true;


ERROR: MissingPropertyType - src/AppendStream.php:20:13 - Property GuzzleHttp\Psr7\AppendStream::$current does not have a declared type - consider int (see https://psalm.dev/045)
    private $current = 0;


ERROR: MissingPropertyType - src/AppendStream.php:21:13 - Property GuzzleHttp\Psr7\AppendStream::$pos does not have a declared type - consider int (see https://psalm.dev/045)
    private $pos = 0;


ERROR: MissingReturnType - src/AppendStream.php:55:21 - Method GuzzleHttp\Psr7\AppendStream::addStream does not have a return type, expecting void (see https://psalm.dev/050)
    public function addStream(StreamInterface $stream)


ERROR: MixedInferredReturnType - src/AppendStream.php:110:21 - Could not verify return type 'int' for GuzzleHttp\Psr7\AppendStream::tell (see https://psalm.dev/047)
    public function tell()


ERROR: MixedArrayOffset - src/AppendStream.php:142:14 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
             $this->streams[$this->current]->eof());


ERROR: MissingReturnType - src/AppendStream.php:145:21 - Method GuzzleHttp\Psr7\AppendStream::rewind does not have a return type, expecting void (see https://psalm.dev/050)
    public function rewind()


ERROR: MissingReturnType - src/AppendStream.php:155:21 - Method GuzzleHttp\Psr7\AppendStream::seek does not have a return type, expecting void (see https://psalm.dev/050)
    public function seek($offset, $whence = SEEK_SET)


ERROR: MixedArrayOffset - src/AppendStream.php:199:36 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
            if ($progressToNext || $this->streams[$this->current]->eof()) {


ERROR: MixedOperand - src/AppendStream.php:204:17 - Left operand cannot be mixed (see https://psalm.dev/059)
                $this->current++;


ERROR: MixedArrayOffset - src/AppendStream.php:207:23 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
            $result = $this->streams[$this->current]->read($remaining);


ERROR: MixedOperand - src/AppendStream.php:219:9 - Left operand cannot be mixed (see https://psalm.dev/059)
        $this->pos += strlen($buffer);


ERROR: MixedInferredReturnType - src/AppendStream.php:234:21 - Could not verify return type 'bool' for GuzzleHttp\Psr7\AppendStream::isSeekable (see https://psalm.dev/047)
    public function isSeekable()

if we remove same issues that was found by phpstan. Here are extra issue found

ERROR: MixedInferredReturnType - src/AppendStream.php:110:21 - Could not verify return type 'int' for GuzzleHttp\Psr7\AppendStream::tell (see https://psalm.dev/047)
    public function tell()

ERROR: MixedArrayOffset - src/AppendStream.php:142:14 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
             $this->streams[$this->current]->eof());

ERROR: MixedArrayOffset - src/AppendStream.php:199:36 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
            if ($progressToNext || $this->streams[$this->current]->eof()) {


ERROR: MixedOperand - src/AppendStream.php:204:17 - Left operand cannot be mixed (see https://psalm.dev/059)
                $this->current++;


ERROR: MixedArrayOffset - src/AppendStream.php:207:23 - Cannot access value on variable $this->streams using mixed offset (see https://psalm.dev/031)
            $result = $this->streams[$this->current]->read($remaining);


ERROR: MixedOperand - src/AppendStream.php:219:9 - Left operand cannot be mixed (see https://psalm.dev/059)
        $this->pos += strlen($buffer);


ERROR: MixedInferredReturnType - src/AppendStream.php:234:21 - Could not verify return type 'bool' for GuzzleHttp\Psr7\AppendStream::isSeekable (see https://psalm.dev/047)
    public function isSeekable()

I've used current master (3472035ddb363a8452bc6999eeb92a92985879d7), so the lines may change

So with psalm we will have extra type errors found.

---

The link you gave. phpstan and psalm can read each other tool specific annotations (@phpstan-param and @psalm-param, also psalm can read PhpStorm annotations see https://psalm.dev/docs/running_psalm/configuration/#allowphpstormgenerics) so this is not an issue anymore.
But there is still a problem in writing it (annotations) 2 times. The 1st one is for SA tool, and the second one is for IDE (PhpStorm upvote for the support https://youtrack.jetbrains.com/issues/WI?q=sort%20by:%20votes%20State:%20-Fixed%20State:%20-Obsolete%20%20State:%20-Verified%20State:%20-Declined%20%20State:%20-Backlog%20State:%20-Workaround%20State:%20-Duplicate%20sort%20by:%20updated%20). BUT most of the times (80%) one time is enough.

[vv12131415]

@Tobion what's your opinion?

[Tobion]

The psalm errors you listed are already reported by phpstan, just with a different wording.
For example

ERROR: MixedOperand - src/AppendStream.php:219:9 - Left operand cannot be mixed (see >https://psalm.dev/059)
$this->pos += strlen($buffer);

in phpstan is reported that there is no type specified for AppendStream::$pos.

To me there is no point in using phpstan and psalm at the same time. If you find concrete examples where it would help please open a PR.
For the time being it's more important to fix the existing phpstan warnings, which I started in #333. Feel free to also help in this regard. Thanks.