Ruby: allow speculative container qname resolution

Author: asgerf

ruby/ql/lib/codeql/ruby/ast/internal/Module.qll

@@ -1,4 +1,5 @@
 private import codeql.ruby.AST
+private import Scope as Scope
 
 // Names of built-in modules and classes
 private string builtin() {
@@ -16,6 +17,8 @@ private module Cached {
     TResolved(string qName) {
       qName = builtin()
       or
+      qName = getAnAssumedGlobalConst()
+      or
       qName = namespaceDeclaration(_)
     } or
     TUnresolved(Namespace n) { not exists(namespaceDeclaration(n)) }
@@ -65,7 +68,7 @@ private module Cached {
     (
       m = resolveConstantReadAccess(c.getReceiver())
       or
-      m = enclosingModule(c).getModule() and
+      m = enclosingModuleNoBlock(c).getModule() and
       c.getReceiver() instanceof SelfVariableAccess
     ) and
     result = resolveConstantReadAccess(c.getAnArgument())
@@ -388,11 +391,27 @@ private module ResolveImpl {
     result = resolveConstantWriteAccessRec(c, _, _)
   }
 
+  /**
+   * Gets the name of a constant `C` that we assume to be defined in the top-level because
+   * it is referenced in a way that can only resolve to a top-level constant.
+   */
+  string getAnAssumedGlobalConst() {
+    exists(ConstantAccess access |
+      not exists(access.getScopeExpr()) and
+      result = access.getName()
+    |
+      access.hasGlobalScope()
+      or
+      // At the top-level but not inside a block
+      enclosingModuleNoBlock(access) instanceof Toplevel
+    )
+  }
+
   pragma[nomagic]
   private string isDefinedConstantNonRec(string container, string name) {
     result = resolveConstantWriteAccessNonRec(_, container, name)
     or
-    result = builtin() and
+    result = [builtin(), getAnAssumedGlobalConst()] and
     name = result and
     container = "Object"
   }
@@ -447,7 +466,7 @@ private module ResolveImpl {
       result = resolveConstantReadAccess(this.getReceiver(), _)
       or
       exists(ModuleBase encl |
-        encl = enclosingModule(this) and
+        encl = enclosingModuleNoBlock(this) and
         result = [qualifiedModuleNameNonRec(encl, _, _), qualifiedModuleNameRec(encl, _, _)]
       |
         this.getReceiver() instanceof SelfVariableAccess
@@ -495,23 +514,31 @@ private module ResolveImpl {
 private import ResolveImpl
 
 /**
- * A variant of AstNode::getEnclosingModule that excludes
+ * Gets an enclosing scope of `scope`, stopping at the first module or block.
+ *
+ * Includes `scope` itself and the final module/block.
+ */
+private Scope enclosingScopesNoBlock(Scope scope) {
+  result = scope
+  or
+  not scope instanceof ModuleBase and
+  not scope instanceof Block and
+  result = enclosingScopesNoBlock(scope.getOuterScope())
+}
+
+/**
+ * A variant of `AstNode::getEnclosingModule` that excludes
  * results that are enclosed in a block. This is a bit wrong because
  * it could lead to false negatives. However, `include` statements in
  * blocks are very rare in normal code. The majority of cases are in calls
  * to methods like `module_eval` and `Rspec.describe` / `Rspec.context`. These
  * methods evaluate the block in the context of some other module/class instead of
  * the enclosing one.
  */
-private ModuleBase enclosingModule(AstNode node) {
-  result = node.getParent()
-  or
-  exists(AstNode mid |
-    result = enclosingModule(mid) and
-    mid = node.getParent() and
-    not mid instanceof ModuleBase and
-    not mid instanceof Block
-  )
+private ModuleBase enclosingModuleNoBlock(Stmt node) {
+  // Note: don't rely on AstNode.getParent() here.
+  // Instead use Scope.getOuterScope() to correctly handle the scoping of things like Namespace.getScopeExpr().
+  result = enclosingScopesNoBlock(Scope::scopeOfInclSynth(node))
 }
 
 private Module getAncestors(Module m) {

ruby/ql/test/library-tests/modules/ancestors.expected

@@ -1,6 +1,14 @@
 #-----| Class
 #-----| super -> Module
 
+#-----| EsotericInstanceMethods
+
+#-----| MyStruct
+
+#-----| Struct
+
+#-----| UnresolvedNamespace
+
 #-----| BasicObject
 
 #-----| Complex
@@ -244,8 +252,8 @@ unresolved_subclass.rb:
 #    1| ResolvableBaseClass
 #-----| super -> Object
 
-#    4| ...::Subclass1
+#    4| UnresolvedNamespace::Subclass1
 #-----| super -> ResolvableBaseClass
 
-#    7| ...::Subclass2
-#-----| super -> Object
+#    7| UnresolvedNamespace::Subclass2
+#-----| super -> UnresolvedNamespace::Subclass1

ruby/ql/test/library-tests/modules/callgraph.expected

@@ -281,6 +281,7 @@ getTarget
 | private.rb:104:1:104:20 | call to new | calls.rb:117:5:117:16 | new |
 | private.rb:104:1:104:28 | call to call_m1 | private.rb:91:3:93:5 | call_m1 |
 | private.rb:105:1:105:20 | call to new | calls.rb:117:5:117:16 | new |
+| toplevel_self_singleton.rb:18:12:22:1 | call to new | calls.rb:117:5:117:16 | new |
 | toplevel_self_singleton.rb:30:13:30:19 | call to call_me | toplevel_self_singleton.rb:26:9:27:11 | call_me |
 | toplevel_self_singleton.rb:31:13:31:20 | call to call_you | toplevel_self_singleton.rb:29:9:32:11 | call_you |
 unresolvedCall
@@ -372,7 +373,6 @@ unresolvedCall
 | toplevel_self_singleton.rb:8:1:16:3 | call to do_something |
 | toplevel_self_singleton.rb:10:9:10:27 | call to ab_singleton_method |
 | toplevel_self_singleton.rb:14:9:14:27 | call to ab_singleton_method |
-| toplevel_self_singleton.rb:18:12:22:1 | call to new |
 | toplevel_self_singleton.rb:20:9:20:27 | call to ab_singleton_method |
 privateMethod
 | calls.rb:1:1:3:3 | foo |

ruby/ql/test/library-tests/modules/methods.expected

@@ -602,12 +602,12 @@ lookupMethod
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass | new | calls.rb:117:5:117:16 | new |
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass | puts | calls.rb:102:5:102:30 | puts |
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass | to_s | calls.rb:172:5:173:7 | to_s |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 | new | calls.rb:117:5:117:16 | new |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 | puts | calls.rb:102:5:102:30 | puts |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 | to_s | calls.rb:172:5:173:7 | to_s |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 | new | calls.rb:117:5:117:16 | new |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 | puts | calls.rb:102:5:102:30 | puts |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 | to_s | calls.rb:172:5:173:7 | to_s |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 | new | calls.rb:117:5:117:16 | new |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 | puts | calls.rb:102:5:102:30 | puts |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 | to_s | calls.rb:172:5:173:7 | to_s |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 | new | calls.rb:117:5:117:16 | new |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 | puts | calls.rb:102:5:102:30 | puts |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 | to_s | calls.rb:172:5:173:7 | to_s |
 enclosingMethod
 | calls.rb:2:5:2:14 | call to puts | calls.rb:1:1:3:3 | foo |
 | calls.rb:2:5:2:14 | self | calls.rb:1:1:3:3 | foo |

ruby/ql/test/library-tests/modules/modules.expected

@@ -35,14 +35,18 @@ getModule
 | file://:0:0:0:0 | BasicObject |
 | file://:0:0:0:0 | Class |
 | file://:0:0:0:0 | Complex |
+| file://:0:0:0:0 | EsotericInstanceMethods |
 | file://:0:0:0:0 | FalseClass |
 | file://:0:0:0:0 | Float |
+| file://:0:0:0:0 | MyStruct |
 | file://:0:0:0:0 | NilClass |
 | file://:0:0:0:0 | Numeric |
 | file://:0:0:0:0 | Proc |
 | file://:0:0:0:0 | Rational |
+| file://:0:0:0:0 | Struct |
 | file://:0:0:0:0 | Symbol |
 | file://:0:0:0:0 | TrueClass |
+| file://:0:0:0:0 | UnresolvedNamespace |
 | hello.rb:1:1:8:3 | EnglishWords |
 | hello.rb:11:1:16:3 | Greeting |
 | hello.rb:18:1:22:3 | HelloWorld |
@@ -86,8 +90,8 @@ getModule
 | toplevel_self_singleton.rb:2:5:5:7 | A::B |
 | toplevel_self_singleton.rb:24:1:34:3 | Good |
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 |
 getADeclaration
 | calls.rb:21:1:34:3 | M | calls.rb:21:1:34:3 | M |
 | calls.rb:43:1:58:3 | C | calls.rb:43:1:58:3 | C |
@@ -181,8 +185,8 @@ getADeclaration
 | toplevel_self_singleton.rb:2:5:5:7 | A::B | toplevel_self_singleton.rb:2:5:5:7 | B |
 | toplevel_self_singleton.rb:24:1:34:3 | Good | toplevel_self_singleton.rb:24:1:34:3 | Good |
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 | unresolved_subclass.rb:4:1:5:3 | Subclass1 |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 | unresolved_subclass.rb:7:1:8:3 | Subclass2 |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 | unresolved_subclass.rb:4:1:5:3 | Subclass1 |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 | unresolved_subclass.rb:7:1:8:3 | Subclass2 |
 getSuperClass
 | calls.rb:43:1:58:3 | C | calls.rb:115:1:118:3 | Object |
 | calls.rb:65:1:69:3 | D | calls.rb:43:1:58:3 | C |
@@ -239,8 +243,8 @@ getSuperClass
 | private.rb:96:1:102:3 | PrivateOverride2 | private.rb:82:1:94:3 | PrivateOverride1 |
 | toplevel_self_singleton.rb:2:5:5:7 | A::B | calls.rb:115:1:118:3 | Object |
 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass | calls.rb:115:1:118:3 | Object |
-| unresolved_subclass.rb:4:1:5:3 | ...::Subclass1 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass |
-| unresolved_subclass.rb:7:1:8:3 | ...::Subclass2 | calls.rb:115:1:118:3 | Object |
+| unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 | unresolved_subclass.rb:1:1:2:3 | ResolvableBaseClass |
+| unresolved_subclass.rb:7:1:8:3 | UnresolvedNamespace::Subclass2 | unresolved_subclass.rb:4:1:5:3 | UnresolvedNamespace::Subclass1 |
 getAPrependedModule
 | calls.rb:115:1:118:3 | Object | calls.rb:171:1:174:3 | A |
 | calls.rb:171:1:174:3 | A | toplevel_self_singleton.rb:2:5:5:7 | A::B |
@@ -318,6 +322,11 @@ resolveConstantReadAccess
 | calls.rb:471:5:471:11 | Array | Array |
 | calls.rb:477:5:477:9 | Class | Class |
 | calls.rb:483:5:483:11 | Array | Array |
+| calls.rb:490:1:490:23 | EsotericInstanceMethods | EsotericInstanceMethods |
+| calls.rb:491:1:491:23 | EsotericInstanceMethods | EsotericInstanceMethods |
+| calls.rb:492:1:492:23 | EsotericInstanceMethods | EsotericInstanceMethods |
+| calls.rb:493:1:493:23 | EsotericInstanceMethods | EsotericInstanceMethods |
+| calls.rb:494:1:494:23 | EsotericInstanceMethods | EsotericInstanceMethods |
 | calls.rb:504:1:504:21 | ExtendSingletonMethod | ExtendSingletonMethod |
 | calls.rb:507:12:507:32 | ExtendSingletonMethod | ExtendSingletonMethod |
 | calls.rb:510:1:510:22 | ExtendSingletonMethod2 | ExtendSingletonMethod2 |
@@ -383,7 +392,12 @@ resolveConstantReadAccess
 | private.rb:100:7:100:22 | PrivateOverride1 | PrivateOverride1 |
 | private.rb:104:1:104:16 | PrivateOverride2 | PrivateOverride2 |
 | private.rb:105:1:105:16 | PrivateOverride2 | PrivateOverride2 |
+| toplevel_self_singleton.rb:18:12:18:17 | Struct | Struct |
+| unresolved_subclass.rb:4:7:4:25 | UnresolvedNamespace | UnresolvedNamespace |
 | unresolved_subclass.rb:4:40:4:58 | ResolvableBaseClass | ResolvableBaseClass |
+| unresolved_subclass.rb:7:7:7:25 | UnresolvedNamespace | UnresolvedNamespace |
+| unresolved_subclass.rb:7:40:7:58 | UnresolvedNamespace | UnresolvedNamespace |
+| unresolved_subclass.rb:7:40:7:69 | Subclass1 | UnresolvedNamespace::Subclass1 |
 resolveConstantWriteAccess
 | calls.rb:21:1:34:3 | M | M |
 | calls.rb:43:1:58:3 | C | C |

ruby/ql/test/library-tests/modules/superclasses.expected

@@ -1,6 +1,14 @@
 #-----| Class
 #-----|  -> Module
 
+#-----| EsotericInstanceMethods
+
+#-----| MyStruct
+
+#-----| Struct
+
+#-----| UnresolvedNamespace
+
 #-----| BasicObject
 
 #-----| Complex
@@ -235,8 +243,8 @@ unresolved_subclass.rb:
 #    1| ResolvableBaseClass
 #-----|  -> Object
 
-#    4| ...::Subclass1
+#    4| UnresolvedNamespace::Subclass1
 #-----|  -> ResolvableBaseClass
 
-#    7| ...::Subclass2
-#-----|  -> Object
+#    7| UnresolvedNamespace::Subclass2
+#-----|  -> UnresolvedNamespace::Subclass1