Double quote usage

[kynx]

Squiz.Strings.DoubleQuoteUsage.ContainsVar prevents strings containing variables. This doesn't match the examples in the documentation and, given that PHP7s interpolation uses less memory than concatenation, probably isn't intended.

This PR adds an exclude for that check and tries to make the docs a little more exact.

[geerteltink]

... given that PHP7s interpolation uses less memory than concatenation ...

I completely missed that part. Here's an in depth review: https://blog.blackfire.io/php-7-performance-improvements-encapsed-strings-optimization.html

[geerteltink]

Change to: "Invalid: There are no variables or control characters inside double quote strings."

[geerteltink]

Maybe we should remove this example as interpolation would be better. In this case it would end up the same as the first example: "Hello There\n";

[geerteltink]

You need to update test/expected-report.txt as the report is different after changing the rules. Not sure how I did it, but I guess I ran the tests and just copy pasted phpcs.log into that file.

[kynx]

Thanks for the review @xtreamwayz . It'd be worth keeping an eye on squizlabs/PHP_CodeSniffer#2259 for a more comprehensive sniff.

[geerteltink]

I saw that this morning. Looks like it's just an idea. No PR yet.

[Xerkus]

I believe our rule is that double quoted string can not contain vars or other variable interpolation and sprintf should be used instead for reasons related to QA and not performance.
This coding standard rule reflects the rule we've been following in our reviews, so I say it should stay.

[weierophinney]

I believe our rule is that double quoted string can not contain vars or other variable interpolation and sprintf should be used instead for reasons related to QA and not performance.
This coding standard rule reflects the rule we've been following in our reviews, so I say it should stay.

The main reasons I've advocated usage of sprintf() are:

• performance
• readability

Both of these were informed by performance of previous PHP versions with regards to string interpolation. Interpolation was known to be slow, and escaping rules tend to get messy. Concatenation is predictable, but hard to read. sprintf() semantics are relatively easy to understand, and generally performant, making it a good solution to these problems. (For the record, str_replace() using named placeholders is also quite performant.)

However, if PHP 7 solves most of the performance issues, string interpolation would likely be a viable choice again. As such, I've got an open question to Julien Pauli asking what the performance differences are between the two approaches.

[weierophinney]

This repository has been closed and moved to laminas/laminas-coding-standard; a new issue has been opened at laminas/laminas-coding-standard#4.

[weierophinney]

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