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I am trying to parse a recursive directory of PHP files using the built in PHP linter, which works like this:

$ php -l good.php
No syntax errors detected in good.php

$ php -l bad.php
PHP Parse error:  syntax error, unexpected ''foo'' (T_CONSTANT_ENCAPSED_STRING), expecting ')' in bad.php on line 3
Errors parsing bad.php

We can see that files which pass linting output a line containing No syntax errors and those which fail linting output a line containing Errors parsing.

I see that I have 12147 PHP files recursively in the current directory, however the PHP linter is only outputting seven lines:

$ find . -name \*.php -print0 | xargs -0 ls -l | wc -l
12147

$ find . -name \*.php -print0 | xargs -0 php -l | wc -l
7

As there were only 7 files parsed by PHP, I can use my head with ls to find some files which have not been parsed:

$ find . -name \*.php -print0 | xargs -0 ls -l | head
-rw-r--r-- 1 dotan dotan      1927 Jan 13 10:13 ./bootstrap/app.php
-rw-r--r-- 1 dotan dotan      1076 Jan 13 10:13 ./bootstrap/autoload.php
-rw-rw-r-- 1 dotan dotan     25620 Mar 12 12:29 ./bootstrap/cache/services.php
-rw-r--r-- 1 dotan dotan      2493 Jan 13 10:13 ./bootstrap/paths.php
-rwxrwxr-x 1 dotan dotan     20008 Mar 12 12:30 ./config/app.php
-rw-r--r-- 1 dotan dotan      3304 Jan 13 10:13 ./config/auth.php
-rw-r--r-- 1 dotan dotan      1819 Jan 13 10:13 ./config/cache.php
-rw-r--r-- 1 dotan dotan      3751 Jan 13 10:13 ./config/cartalyst.sentinel-addons.social.php
-rw-r--r-- 1 dotan dotan      6849 Jan 13 10:13 ./config/cartalyst.sentinel.php
-rw-r--r-- 1 dotan dotan      1020 Jan 13 10:13 ./config/compile.php
xargs: ls: terminated by signal 13

$ find . -name \*.php -print0 | xargs -0 php -l
No syntax errors detected in ./bootstrap/paths.php
No syntax errors detected in ./vendor/watson/validating/src/ValidatingTrait.php
No syntax errors detected in ./vendor/giggsey/libphonenumber-for-php/src/libphonenumber/data/PhoneNumberMetadata_SI.php
No syntax errors detected in ./vendor/php-vcr/php-vcr/src/VCR/Event/BeforePlaybackEvent.php
No syntax errors detected in ./vendor/laravel/framework/src/Illuminate/Support/Facades/Blade.php
No syntax errors detected in ./resources/views/emails/appointment/updated/body.blade.php
No syntax errors detected in ./app/WL/Modules/Location/Commands/RemoveClientLocationCommand.php

Yet, when I try to parse one of those files I see that it does produce the expected output (either passing or failing parsing):

$ php -l ./bootstrap/cache/services.php
No syntax errors detected in ./bootstrap/cache/services.php

I've checked that neither passing nor failing linting is printing the expected lines to stderr:

$ php -l good.php | grep rr
No syntax errors detected in good.php

$ php -l bad.php | grep rr
PHP Parse error:  syntax error, unexpected ''foo'' (T_CONSTANT_ENCAPSED_STRING), expecting ')' in bad.php on line 3
Errors parsing bad.php

What should I check now? My end goal is to lint all the files, then grep for Error parsing to fix those issues.

  • 1
    Can the php -l command take multiple arguments with the syntax php -l file1 file2 file3? xargs would be passing the results of find in batches. – Haxiel Mar 12 at 13:50
  • @Haxiel: Thank you, in fact xargs was batching. Learn something every day! – dotancohen Mar 12 at 14:17
7

To see whether xargs makes a difference, run the command lines that it runs. Here are a couple of ways to see exactly what it runs, while not risking changing what it runs:

  • Write a script called php in a temporary directory and put it at the beginning of $PATH. In this script, log the arguments (and optionally run the real php afterwards).
  • Run the whole command line under a logging mechanism such as strace.

You will find that the command is something like

php -l ./bootstrap/app.php ./bootstrap/autoload.php ./bootstrap/cache/services.php …

The next step is to investigate what this command does.

I'm not familiar with php but I guess it only treats the first file name as a PHP script name, and that in lint mode it simply ignores all subsequent arguments. So you need to run php -l once for each script, 12147 times in total, instead of using xargs's grouping behavior.

The easiest way to do that is

find . -name \*.php -exec php -l {} \;

but this command will always return 0 even if some invocations of php return a nonzero status. While find mostly doesn't need xargs in the 21st century, a benefit of xargs is that it returns a nonzero status if any invocation of the command returns a nonzero status. So run xargs, but tell it to only process one file at a time with the -n option.

find . -name \*.php -print0 | xargs -0 -n 1 php -l
  • As usual, you've hit the nail right on the head. xargs was batching the arguments, and the -n 1 flag was the right solution. In fact I was using -exec to continue working while this question was being resolved, but I prefer xargs as I feel it is a more flexible solution. Thank you. – dotancohen Mar 12 at 14:15

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