Bug #75868 [Com]: is_resource() gettype() get_resources() inconsistent result on closed resource

Edit report at https://bugs.php.net/bug.php?id=75868&edit=1 ID: 75868 Comment by: salsi at icosaedro dot it Reported by: bobonov at gmail dot com Summary: is_resource() gettype() get_resources() inconsistent result on closed resource Status: Re-Opened Type: Bug Package: Variables related Operating System: Ubuntu 17.10 PHP Version: 7.2.1 Block user comment: N Private report: N New Comment: For the record, closed resources are "unknown type"s (or "resource (closed)" since PHP 7.2.0) according to gettype() and are not resources at all according to is_resource(), but these values are still reported as resource in the stack trace, for example: <?php // Set a safe environment: error_reporting(-1); // Maps errors to ErrorException. function my_error_handler($errno, $message) { throw new ErrorException($message); } set_error_handler("my_error_handler"); $f = fopen(__FILE__, "r"); fclose($f); fclose($f); # double close -- here fails, as expected ?> displays: PHP Fatal error: Uncaught exception 'ErrorException' with message 'fclose(): 5 is not a valid stream resource' in C:\Users\UmbertoSalsi\Desktop\php\resource.php:7 Stack trace: #0 [internal function]: my_error_handler(2, 'fclose(): 5 is ...', 'C:\\Users\\Umbert...', 13, Array) #1 C:\Users\UmbertoSalsi\Desktop\php\resource.php(13): fclose(Resource id #5) #2 {main} thrown in C:\Users\UmbertoSalsi\Desktop\php\resource.php on line 7 Fatal error: Uncaught exception 'ErrorException' with message 'fclose(): 5 is not a valid stream resource' in C:\Users\UmbertoSalsi\Desktop\php\resource.php:7 Stack trace: #0 [internal function]: my_error_handler(2, 'fclose(): 5 is ...', 'C:\\Users\\Umbert...', 13, Array) #1 C:\Users\UmbertoSalsi\Desktop\php\resource.php(13): fclose(Resource id #5) #2 {main} thrown in C:\Users\UmbertoSalsi\Desktop\php\resource.php on line 7 Note the "fclose(): 5 is not a valid stream resource" and then the following "fclose(Resource id #5)" above: it's all a bit confusing. I still do not understand what a program should do to safely detect the type of a value at runtime. Previous Comments: ------------------------------------------------------------------------ [2018-01-26 08:09:02] bobonov at gmail dot com I do not say that my proposal is correct, probably is deeply wrong. I only see it as the more logical (and probably I'm wrong again). And eventually being the more logical does not imply that is the best solution. A different solution would move the problem in another function. I say that there is a general consistency problem of the results from different function. So if leaving is_resource() untouched is the best solution (why not) the issue is still there. Then if you think that the problem (because I hope you do not deny that there is a consistency problem) is not a problem, then close the bug. ------------------------------------------------------------------------ [2018-01-25 16:00:16] cmb@php.net > I know that is the intend behavior, as clearly reported in the > documentation, but anyway it is a bug. If you insist. ------------------------------------------------------------------------ [2018-01-25 15:19:48] spam2 at rhsoft dot net and how do you imagine is_resource() to be useful when it answers yes ona closed one which can't be used in the next line? changing that would be a regression and break existing code for no purpose ------------------------------------------------------------------------ [2018-01-25 15:16:39] bobonov at gmail dot com In the title I reported it as "inconsistent result on closed resource". I know that is the intend behavior, as clearly reported in the documentation, but anyway it is a bug. While 2 function report it as still a resource, is_resource() say is not a resource. Yes gettype() report it as "resource (closed)" which in my opinion is a strange type since closed denote a status not a variable type, or at least resource type We have 3 different result checking the same variable is_resource() say is a resource gettype() report "resource (closed)" (which in php does not exist) get_resources() which still list it as resource To make more clear the inconsistent type checking by different function for a resource I made a bit more complete script (in which you can see that var_dump() get_resource_type() still see closed one as resource). In particular get_resource_type() give a warning when used to test a non resource type. "PHP Warning: get_resource_type() expects parameter 1 to be resource, string given" So if even the runtime see closed resource as resource... it is a resource <?php function testResource($a) { echo "$a\n"; echo "gettype(): " . gettype($a)."\n"; echo "is_resource():"; var_dump(is_resource($a)); echo "get_resource_type(): " . get_resource_type ( $a )."\n"; echo "get_resources():"; print_r(get_resources()); echo "var_dump():"; var_dump($a); } $a = fopen('http://www.google.com', 'r'); echo "OPEN resource\n"; testResource($a); fclose($a); echo "\n\n\nCLOSED resource\n"; testResource($a); ?> this script will produce the following result: OPEN resource Resource id #6 gettype(): resource is_resource():bool(true) get_resource_type(): stream get_resources():Array ( [1] => Resource id #1 [2] => Resource id #2 [3] => Resource id #3 [4] => Resource id #4 [6] => Resource id #6 ) var_dump():resource(6) of type (stream) CLOSED resource Resource id #6 gettype(): resource (closed) is_resource():bool(false) get_resource_type(): Unknown get_resources():Array ( [1] => Resource id #1 [2] => Resource id #2 [3] => Resource id #3 [4] => Resource id #4 [6] => Resource id #6 ) var_dump():resource(6) of type (Unknown) Probably the correct output (to make everything consistent and logic) for a closed resource should be: gettype(): resource is_resource():bool(true) get_resource_type(): closed var_dump():resource(6) of type (closed) All "resource provider" should change a resource type to closed when *close() is called. ------------------------------------------------------------------------ [2018-01-25 13:41:46] cmb@php.net > Checking the closed resource with: > is_resource() return false. Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php This is documented[1] behavior: | is_resource() is not a strict type-checking method: it will | return FALSE if var is a resource variable that has been closed. [1] <http://www.php.net/manual/en/function.is-resource.php#refsect1-function.is-resource-notes> ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=75868 -- Edit this bug report at https://bugs.php.net/bug.php?id=75868&edit=1