htmlspecialchars can return non-empty-string

[still-dreaming-1]

https://psalm.dev/r/397951a5d7

The example code shows the issue I am trying to fix. If the code has already done something to guarantee a value is a non-empty-string, there are several built in functions you could pass it to that should then also return a non-empty-string. This will prevent redundant checks and added runtime in projects making use of non-empty-string. This pull request is only changing this one function for now, but if it is accepted I will probably change additional similar functions.

I don't really understand @psalm-flow, hopefully this added @psalm-return does not interfere? Is there a better approach where @psalm-flow could always imply starting from a non-empty-string would return one (again speaking from a place of not understanding @psalm-flow).

I looked for a good place to add tests for this change, but I'm lost on that front. Can someone recommend something, or is this a change that would be overkill to explicitly test?

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/397951a5d7

<?php

/**
 * @param non-empty-string $value
 * @return non-empty-string
 */
function escapeForHtml(string $value): string
{
    return \htmlspecialchars($value);
}

Psalm output (using commit ff0c1ce):

INFO: LessSpecificReturnStatement - 9:12 - The type 'string' is more general than the declared return type 'non-empty-string' for escapeForHtml

INFO: MoreSpecificReturnType - 5:12 - The declared return type 'non-empty-string' for escapeForHtml is more specific than the inferred return type 'string'

[muglug]

Thanks!