PhpStorm won't open xdebug profiler snapshot file - php

Question

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Ignore this post. A much simpler statement of this issue can be found at PHP auto_prepend_file causes xdebug profiler to fail
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Original Post (and updates)
When I try to open an xdebug profiler snapshot within PhpStorm using:
menu bar >> Tools >> Analyze xdebug profiler snapshot...
I select the file xDebug created but I'm faced with this error:
Error: Incorrect profiler snapshot format: Incorrect name format
I did not rename the snapshot. It is the default name: cachegrind.out.8008
php.ini
<!-- language:lang-none -->
[xdebug]
zend_extension="php_xdebug-2.5.5-5.6-vc11.dll"
xdebug.remote_enable=1
xdebug.remote_host=localhost
xdebug.remote_port=9000
xdebug.remote_autostart=1
xdebug.profiler_enable=1
xdebug.profiler_output_dir="C:\websites\xdebug"
; xdebug.profiler_output_name= ; Commented out to allow default name
xdebug.idekey=PHPSTORM
Why won't PhpStorm open the snapshot? Should I set a custom xdebug.profiler_output_name option?
Update
I closed all my projects, upgraded from PhpStorm 2017.1.4 to 2017.2, restarted Apache, deleted the old snapshots and created a new one. The new one opens without trouble.
Update 2
Seems that if I run a file from the command line by calling >php script.php, the generated snapshot can be opened. If I run the same file from the browser (meaning I go through the Apache webserver: localhost/script.php) the snapshot cannot be opened.
Update 3
I also notice that when I execute from the browser, I can't delete the snapshot until I force-stop the Apache process. The PHP file I'm profiling has no instructions: just <?php. Below are the two snapshots created:
When executed from the command line (PhpStorm opens this file without problem):
version: 1
creator: xdebug 2.5.5 (PHP 5.6.1-dev)
cmd: C:\path\to\script.php
part: 1
positions: line
events: Time
fl=(1) C:\path\to\script.php
fn=(1) {main}
summary: 0
1 0
When executed from the browser (PhpStorm cannot open this snapshot):
version: 1
creator: xdebug 2.5.5 (PHP 5.6.1-dev)
cmd: C:\path\to\script.php
part: 1
positions: line
events: Time
fl=(2) C:\path\to\script.php
fn=(1)
summary: 0
1 0
Update 4
The culprit is the auto_prepend_file ini setting. I had the following set in Apache Vhosts:
php_value auto_prepend_file "C:\path\to\init.php"
This file is run before Apache executes the script that was called from the browser. When I run the script from the command line, this setting (which is in my Apache Vhosts config) never takes effect so init.php doesn't run. Conversely, if I move the setting to php.ini where it also affects command-line execution, then snapshots generated from the command-line also stop working.
If I remove the auto_prepend_file setting, the generated profiler snapshot can be open without problem in PhpStorm. Of course this isn't a fix since I need the auto_prepend_file to execute for my application to work properly.