fix: propagate return value modifications

[pdelewski]

Without additional echo call in helloWorld, code for main looks as follows
$_main: ; (lines=4, args=0, vars=0, tmps=1) ; (after optimizer) ; /Users/pdelewski/Projects/php-auto/test3.php:1-8 0000 INIT_FCALL 1 112 string("var_dump") 0001 SEND_VAL int(1) 1 0002 DO_ICALL 0003 RETURN int(1)

which means that call to helloWorld has been optimized out and in result hooks are not invoked

[brettmc]

It seems like whether a call is optimized away is out of our control, so do we need a warning in the documentation about this? Is there a good guide already in existence on when this might happen, that we could link to?

[pdelewski]

It seems like whether a call is optimized away is out of our control, so do we need a warning in the documentation about this? Is there a good guide already in existence on when this might happen, that we could link to?

Don't know about guide. Will try to figure out whether observer api can do something about it.

[brettmc]

@pdelewski I think it's ok for now to just add a one-line warning to the usage section of readme, then I'll merge it.

[pdelewski]

@pdelewski I think it's ok for now to just add a one-line warning to the usage section of readme, then I'll merge it.

@brettmc ok, done.