Eagerly initialize Environment._globalModules (#952)

We had been lazily initializing this to be more efficient when no
global modules were used, but this meant that the object wasn't shared
with closures created for mixins and functions that were created when
it was still `null`, so later imported forwards weren't visible to
those members.

Author: nex3

CHANGELOG.md

@@ -6,6 +6,9 @@
 * Don't throw errors if the exact same member is loaded or forwarded from
   multiple modules at the same time.
 
+* Fix a bug where imported forwarded members weren't visible in mixins and
+  functions that were defined before the `@import`.
+
 ## 1.25.2
 
 * Fix a bug where, under extremely rare circumstances, a valid variable could

lib/src/async_environment.dart

@@ -40,15 +40,11 @@ class AsyncEnvironment {
   final Map<String, AstNode> _namespaceNodes;
 
   /// The namespaceless modules used in the current scope.
-  ///
-  /// This is `null` if there are no namespaceless modules.
-  Set<Module> _globalModules;
+  final Set<Module> _globalModules;
 
   /// A map from modules in [_globalModules] to the nodes whose spans
   /// indicate where those modules were originally loaded.
-  ///
-  /// This is `null` if there are no namespaceless modules.
-  Map<Module, AstNode> _globalModuleNodes;
+  final Map<Module, AstNode> _globalModuleNodes;
 
   /// The modules forwarded by this module.
   ///
@@ -153,8 +149,8 @@ class AsyncEnvironment {
   AsyncEnvironment({bool sourceMap = false})
       : _modules = {},
         _namespaceNodes = {},
-        _globalModules = null,
-        _globalModuleNodes = null,
+        _globalModules = {},
+        _globalModuleNodes = {},
         _forwardedModules = null,
         _forwardedModuleNodes = null,
         _nestedForwardedModules = null,
@@ -216,8 +212,8 @@ class AsyncEnvironment {
   AsyncEnvironment forImport() => AsyncEnvironment._(
       {},
       {},
-      null,
-      null,
+      {},
+      {},
       null,
       null,
       null,
@@ -240,8 +236,6 @@ class AsyncEnvironment {
   /// with the same name as a variable defined in this environment.
   void addModule(Module module, AstNode nodeWithSpan, {String namespace}) {
     if (namespace == null) {
-      _globalModules ??= {};
-      _globalModuleNodes ??= {};
       _globalModules.add(module);
       _globalModuleNodes[module] = nodeWithSpan;
       _allModules.add(module);
@@ -337,8 +331,6 @@ class AsyncEnvironment {
       var forwarded = module._environment._forwardedModules;
       if (forwarded == null) return;
 
-      _globalModules ??= {};
-      _globalModuleNodes ??= {};
       _forwardedModules ??= [];
       _forwardedModuleNodes ??= {};
 
@@ -487,8 +479,6 @@ class AsyncEnvironment {
   /// required, since some nodes need to do real work to manufacture a source
   /// span.
   AstNode _getVariableNodeFromGlobalModule(String name) {
-    if (_globalModules == null) return null;
-
     // We don't need to worry about multiple modules defining the same variable,
     // because that's already been checked by [getVariable].
     for (var module in _globalModules) {
@@ -558,7 +548,7 @@ class AsyncEnvironment {
 
       // If this module doesn't already contain a variable named [name], try
       // setting it in a global module.
-      if (!_variables.first.containsKey(name) && _globalModules != null) {
+      if (!_variables.first.containsKey(name)) {
         var moduleWithName = _fromOneModule(name, "variable",
             (module) => module.variables.containsKey(name) ? module : null);
         if (moduleWithName != null) {
@@ -861,8 +851,6 @@ class AsyncEnvironment {
       }
     }
 
-    if (_globalModules == null) return null;
-
     T value;
     Object identity;
     for (var module in _globalModules) {

lib/src/environment.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_environment.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: db31838dbc5c44989803274acb581263e98b488d
+// Checksum: df5ee8bde1eec6e47c1d025041921aba01637696
 //
 // ignore_for_file: unused_import
 
@@ -46,15 +46,11 @@ class Environment {
   final Map<String, AstNode> _namespaceNodes;
 
   /// The namespaceless modules used in the current scope.
-  ///
-  /// This is `null` if there are no namespaceless modules.
-  Set<Module<Callable>> _globalModules;
+  final Set<Module<Callable>> _globalModules;
 
   /// A map from modules in [_globalModules] to the nodes whose spans
   /// indicate where those modules were originally loaded.
-  ///
-  /// This is `null` if there are no namespaceless modules.
-  Map<Module<Callable>, AstNode> _globalModuleNodes;
+  final Map<Module<Callable>, AstNode> _globalModuleNodes;
 
   /// The modules forwarded by this module.
   ///
@@ -159,8 +155,8 @@ class Environment {
   Environment({bool sourceMap = false})
       : _modules = {},
         _namespaceNodes = {},
-        _globalModules = null,
-        _globalModuleNodes = null,
+        _globalModules = {},
+        _globalModuleNodes = {},
         _forwardedModules = null,
         _forwardedModuleNodes = null,
         _nestedForwardedModules = null,
@@ -222,8 +218,8 @@ class Environment {
   Environment forImport() => Environment._(
       {},
       {},
-      null,
-      null,
+      {},
+      {},
       null,
       null,
       null,
@@ -247,8 +243,6 @@ class Environment {
   void addModule(Module<Callable> module, AstNode nodeWithSpan,
       {String namespace}) {
     if (namespace == null) {
-      _globalModules ??= {};
-      _globalModuleNodes ??= {};
       _globalModules.add(module);
       _globalModuleNodes[module] = nodeWithSpan;
       _allModules.add(module);
@@ -344,8 +338,6 @@ class Environment {
       var forwarded = module._environment._forwardedModules;
       if (forwarded == null) return;
 
-      _globalModules ??= {};
-      _globalModuleNodes ??= {};
       _forwardedModules ??= [];
       _forwardedModuleNodes ??= {};
 
@@ -494,8 +486,6 @@ class Environment {
   /// required, since some nodes need to do real work to manufacture a source
   /// span.
   AstNode _getVariableNodeFromGlobalModule(String name) {
-    if (_globalModules == null) return null;
-
     // We don't need to worry about multiple modules defining the same variable,
     // because that's already been checked by [getVariable].
     for (var module in _globalModules) {
@@ -565,7 +555,7 @@ class Environment {
 
       // If this module doesn't already contain a variable named [name], try
       // setting it in a global module.
-      if (!_variables.first.containsKey(name) && _globalModules != null) {
+      if (!_variables.first.containsKey(name)) {
         var moduleWithName = _fromOneModule(name, "variable",
             (module) => module.variables.containsKey(name) ? module : null);
         if (moduleWithName != null) {
@@ -867,8 +857,6 @@ class Environment {
       }
     }
 
-    if (_globalModules == null) return null;
-
     T value;
     Object identity;
     for (var module in _globalModules) {