you called “include*()” or “require*()” on this filename already<\/p><\/blockquote>\n
you called “include*()” or “require*()” on this filename AT THIS SCOPE already<\/p><\/blockquote>\n
What? TWO definitions? Well, yes, dear reader, because most humans will pick the first definition. It appears correct. And for IMP and EXT – by definition – it is correct, since they ignore scope. However, sadly, INC and INT explicitly require scope to be obeyed, and they *require* the second definition to be used.<\/p>\n
Guess which definition PHP uses? Bearing in mind that PHP *treats the include() file differently* depending upon which scope it’s imported at…<\/p>\n
Did you guess the second option? Ha! Wrong!<\/p>\n
And so, in PHP, it’s easy to write something like this:<\/p>\n
\r\nfile 1:\r\nif( !isset( $A) )\r\n $A = \"not blank\"\r\n\r\nfile 2:\r\nrun();\r\nfunction run()\r\n{\r\n require_once 'file 1';\r\n require_once 'file 3';\r\n}\r\n\r\nfile 3:\r\ncrashout();\r\nfunction crashout()\r\n{\r\n require_once 'file 1';\r\n if( isset($A) )\r\n echo \"this will never happen!\";\r\n else\r\n echo \"PHP will claim that A is not set, even though\"\r\n . \" it is explicit set in the file that is explicitly included above!\";\r\n}\r\n<\/pre>\nI bashed my head against a wall with this (kind of) problem until I realised what was going on: PHP has a very poor definition of “a file has already been included”.<\/p>\n
And what the heck can you do to workaround this? Actually, I’m not sure yet. I’ve only recently worked out how and why the runtime does what it does. I’ve not yet worked out a simple approach to PHP programming that avoids the above problems, beyond “never use an include* statement from within a function – never ever, under any circumstances”. At least that forces the behaviour to be predictable (NB: as soon as you do an include* from within a function, each and every one of your PHP scripts will potentially cease to work). But it’s very annoying to be actively prevented from ever doing an INC\/INT\/EXT.<\/p>\n","protected":false},"excerpt":{"rendered":"
(aka “why do my include\/require\/include_once\/require_once files not work \/ seem NOT to be included, even though they are?”) PHP has a mechanism for including files inside each other. The architects of PHP didn’t really think much about what they were doing with a lot of the core language features (witness the foolishness over Register Globals), […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[55,20],"tags":[],"_links":{"self":[{"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/posts\/568"}],"collection":[{"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/comments?post=568"}],"version-history":[{"count":0,"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/posts\/568\/revisions"}],"wp:attachment":[{"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/media?parent=568"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/categories?post=568"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/new.t-machine.org\/index.php\/wp-json\/wp\/v2\/tags?post=568"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}