Improve constant string union handling for concat and encapsed string #2057
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| foreach ($constantStrings as $constantString) { | ||
| if ($constantString->getValue() === '') { | ||
| $strings[] = $rightStringType; | ||
| if ($combinedConstantStringsCount > 0 && $combinedConstantStringsCount <= 16) { |
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I noticed that there is also CALCULATE_SCALARS_LIMIT in this class, but it was not used here, so I kept the previous limit.
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@schlndh I really like your extension! I think it can afford to be smarter than asking the database for the types, because database will not tell you: SELECT name FROM users
WHERE name IS NOT NULLThat But I have a suggestion - how did you implement the SQL parser? I know from my colleague it's no easy feat. He's been working on it thoroughly for a long time and he's not even finished yet: https://github.com/SQLFTW/sqlftw In any case, I think you should use an existing parser like that, or at very least, you should extract your parser to a separate library. |
| assertType("'.1.'|'.2.'", ".$float."); | ||
| assertType("'..'|'.1.'", ".$bool."); | ||
| assertType("'..'|'.a.'", ".$nullable."); | ||
| assertType("'.a.0.'|'.a.1.'|'.b.0.'|'.b.1.'", ".$str.$int."); |
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Can you please also provide an example where the logic goes over the limit and the type is simplified again? Thank you.
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@ondrejmirtes Thanks.
At some point yes, but unfortunately it's not yet smart enough to handle the example you've given.
I implemented my own recursive descent parser. OFC it does not cover everything, but it's enough to get started. And since my goal is to analyze queries written by people I don't think I have to worry much about supporting 100% of MariaDB syntax. Most queries will be written in a smaller subset of SQL. Currently, it can partially parse SELECT, UPDATE, INSERT, DELETE and TRUNCATE TABLE queries. The parser handles almost everything that the project I work on uses (at least in queries which are known statically - definitely in the hundreds). The two exceptions are But I definitely agree that it's not easy to write a reasonably compatible parser from scratch. Especially for MariaDB which has a seriously lacking documentation. I randomly discovered it recently, but I haven't had the time to look at it yet. From a brief glance it seems that they focus on MySQL, whereas my focus is on MariaDB. So I suspect that I won't be able to use it.
I did look for existing SQL parsers when I started working on it, but the only thing I found at the time was some old library that 1) didn't support more recent features, and 2) it had a terrible AST. If a suitable MariaDB parser becomes available then I would consider switching to it. But for now I have a parser that mostly covers my needs.
I currently don't have any plans to do that. Yes, strictly speaking it would be more useful for the "open-source community". But realistically nobody is going to use it, or even find out about it. So it would just be more work for me. |
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@schlndh It'd be a pity to do this work and only support MariaDB in the end. The work you're doing would also be applicable to other DB engines. It should be possible to have this functionality in PHPStan one day :) |
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@ondrejmirtes For now it's still in very early stage. We'll see how it goes. |
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Thank you! |
The current behavior of concat and encapsed string is inconsistent when it comes to constant string unions: https://phpstan.org/r/05b25994-3e9f-4509-9d42-cc936b6790ad
I wanted it to behave the same. And I would also like to be able to concat/encaps two unions together.
Motivation:
I have an extension that checks SQL queries. Most queries are just simple constant strings. But sometimes there are options to e.g. filter/order by different columns and such. So there are multiple possible SQLs. The changes introduced by this PR should make it a bit easier to write such queries in a way that allows them to be checked. E.g. I often use encapsed string instead of concat, and it can happen that there are two independent "dynamic" parts of the query (e.g. WHERE and ORDER BY, which is why I also want to be able to concat two unions).