Disable `constant()` from the runtime

Summary: Add options to disable the constant method.

Reviewed By: kmeht

Differential Revision: D10112355

fbshipit-source-id: f7fd7d6726822939e59f240bf942e7ef6eafa5fd

hphp/runtime/base/runtime-option.cpp

@@ -434,6 +434,7 @@ uint64_t RuntimeOption::UndefinedConstFallback = 0;
 uint64_t RuntimeOption::DisableAssert = 0;
 bool RuntimeOption::DisallowExecutionOperator = false;
 bool RuntimeOption::DisableVariableVariables = false;
+uint64_t RuntimeOption::DisableConstant = 0;
 
 #ifdef HHVM_DYNAMIC_EXTENSION_DIR
 std::string RuntimeOption::ExtensionDir = HHVM_DYNAMIC_EXTENSION_DIR;
@@ -1226,14 +1227,17 @@ void RuntimeOption::Load(
                  "Hack.Lang.Phpism.DisallowExecutionOperator",
                  DisallowExecutionOperator);
     Config::Bind(DisableVariableVariables, ini, config,
-                  "Hack.Lang.Phpism.DisableVariableVariables",
-                  DisableVariableVariables);
+                 "Hack.Lang.Phpism.DisableVariableVariables",
+                 DisableVariableVariables);
     Config::Bind(DisableDefine, ini, config,
                  "Hack.Lang.Phpism.DisableDefine",
                  DisableDefine);
     Config::Bind(DisableAssert, ini, config,
                  "Hack.Lang.Phpism.DisableAssert",
                  DisableAssert);
+    Config::Bind(DisableConstant, ini, config,
+                 "Hack.Lang.Phpism.DisableConstant",
+                 DisableConstant);
   }
   {
     // Repo

hphp/runtime/base/runtime-option.h

@@ -519,6 +519,10 @@ struct RuntimeOption {
   // Disables PHP's variable variables
   // true => error, false => allows use of variable variables
   static bool DisableVariableVariables;
+  // Disables PHP's constant function
+  // valid values are 0 => enabled (default)
+  // 1 => warning, 2 => error
+  static uint64_t DisableConstant;
   // Disables PHP's define() function
   // valid values are 0 => enabled (default)
   // 1 => warning, 2 => error

hphp/runtime/ext/std/ext_std_misc.cpp

@@ -393,6 +393,13 @@ static Class* getClassByName(const char* name, int len) {
 }
 
 Variant HHVM_FUNCTION(constant, const String& name) {
+  auto const warning = "constant() is deprecated and subject"
+  " to removal from the Hack language";
+  switch (RuntimeOption::DisableConstant) {
+    case 0:  break;
+    case 1:  raise_warning(warning); break;
+    default: raise_error(warning);
+  }
   if (!name.get()) return init_null();
   const char *data = name.data();
   int len = name.length();

hphp/test/slow/phpism/constant.php

@@ -0,0 +1,4 @@
+<?hh
+
+const HELLO = 123;
+echo(constant('HELLO'));

hphp/test/slow/phpism/constant.php.expectf

@@ -0,0 +1,3 @@
+
+Warning: constant() is deprecated and subject to removal from the Hack language in %s on line %d
+123

hphp/test/slow/phpism/constant.php.hphp_opts

@@ -0,0 +1 @@
+-vRuntime.Hack.Lang.Phpism.DisableConstant=1

hphp/test/slow/phpism/constant.php.opts

@@ -0,0 +1 @@
+-vHack.Lang.Phpism.DisableConstant=1

hphp/test/slow/phpism/constant2.php

@@ -0,0 +1,4 @@
+<?hh
+
+const HELLO = 123;
+echo(constant('HELLO'));

hphp/test/slow/phpism/constant2.php.expectf

@@ -0,0 +1,2 @@
+
+Fatal error: constant() is deprecated and subject to removal from the Hack language in %s on line %d

hphp/test/slow/phpism/constant2.php.hphp_opts

@@ -0,0 +1 @@
+-vRuntime.Hack.Lang.Phpism.DisableConstant=2

hphp/test/slow/phpism/constant2.php.opts

@@ -0,0 +1 @@
+-vHack.Lang.Phpism.DisableConstant=2