Add a compatibility "cached" key to the array returned by proc_get_status()

Users who previously would've relied on proc_get_status() failing after
calling it more than one time can now check the "cached" key to see
whether the result was cached. If it is cached, it would've previously
returned a failure in the form of a -1 exit code and the status booleans
all being false.

Author: nielsdos

UPGRADING

@@ -27,9 +27,12 @@ PHP 8.3 UPGRADE NOTES
   . Class constants can now be accessed dynamically using the C::{$name} syntax.
     RFC: https://wiki.php.net/rfc/dynamic_class_constant_fetch
   . Executing proc_get_status() multiple times will now always return the right
-    value. Previously, only the first call of the function returned the right
-    value. Executing proc_close() after proc_get_status() will now also return
-    the right exit code. Previously this would return -1.
+    value on posix systems. Previously, only the first call of the function
+    returned the right value. Executing proc_close() after proc_get_status() will
+    now also return the right exit code. Previously this would return -1.
+    Internally, this works by caching the result on posix systems. If you want
+    the old behaviour, you can check the "cached" key in the array returned by
+    proc_get_status() to check whether the result was cached.
 
 ========================================
 2. New Features

ext/standard/proc_open.c

@@ -404,6 +404,10 @@ PHP_FUNCTION(proc_get_status)
 	running = wstatus == STILL_ACTIVE;
 	exitcode = running ? -1 : wstatus;
 
+	/* The status is always available on Windows and will always read the same,
+	 * even if the child has already exited. This is because the result stays available
+	 * until the child handle is closed. Hence no caching is used on Windows. */
+	add_assoc_bool(return_value, "cached", false);
 #elif HAVE_SYS_WAIT_H
 	wait_pid = waitpid_cached(proc, &wstatus, WNOHANG|WUNTRACED);
 
@@ -426,6 +430,8 @@ PHP_FUNCTION(proc_get_status)
 		 * looking for either does not exist or is not a child of this process */
 		running = 0;
 	}
+
+	add_assoc_bool(return_value, "cached", proc->has_stored_exit_wait_status);
 #endif
 
 	add_assoc_bool(return_value, "running", running);

ext/standard/tests/general_functions/bug39322.phpt

@@ -24,11 +24,13 @@ echo "Done!\n";
 
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["command"]=>
   string(14) "/bin/sleep 120"
   ["pid"]=>
   int(%d)
+  ["cached"]=>
+  bool(false)
   ["running"]=>
   bool(false)
   ["signaled"]=>

ext/standard/tests/general_functions/gh10239_2.phpt

@@ -13,11 +13,13 @@ var_dump(proc_get_status($p));
 var_dump(proc_get_status($p));
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["command"]=>
   string(5) "false"
   ["pid"]=>
   int(%d)
+  ["cached"]=>
+  bool(true)
   ["running"]=>
   bool(false)
   ["signaled"]=>
@@ -31,11 +33,13 @@ array(8) {
   ["stopsig"]=>
   int(0)
 }
-array(8) {
+array(9) {
   ["command"]=>
   string(5) "false"
   ["pid"]=>
   int(%d)
+  ["cached"]=>
+  bool(true)
   ["running"]=>
   bool(false)
   ["signaled"]=>

ext/standard/tests/general_functions/proc_open02.phpt

@@ -32,11 +32,13 @@ echo "Done!\n";
 ?>
 --EXPECTF--
 bool(true)
-array(8) {
+array(9) {
   ["command"]=>
   string(10) "/bin/sleep"
   ["pid"]=>
   int(%d)
+  ["cached"]=>
+  bool(false)
   ["running"]=>
   bool(true)
   ["signaled"]=>
@@ -51,11 +53,13 @@ array(8) {
   int(0)
 }
 bool(true)
-array(8) {
+array(9) {
   ["command"]=>
   string(10) "/bin/sleep"
   ["pid"]=>
   int(%d)
+  ["cached"]=>
+  bool(false)
   ["running"]=>
   bool(false)
   ["signaled"]=>