[c#] create implicit ctor for field inits

joernio · Jan 6, 2025 · a8b16ea · a8b16ea
1 parent ec2b517
commit a8b16ea
Show file tree

Hide file tree

Showing 2 changed files with 52 additions and 11 deletions.
diff --git a/...src2cpg/src/main/scala/io/joern/csharpsrc2cpg/astcreation/AstForDeclarationsCreator.scala b/...src2cpg/src/main/scala/io/joern/csharpsrc2cpg/astcreation/AstForDeclarationsCreator.scala
@@ -1,6 +1,7 @@
 package io.joern.csharpsrc2cpg.astcreation
 
 import io.joern.csharpsrc2cpg.CSharpModifiers
+import io.joern.csharpsrc2cpg.astcreation.AstParseLevel.FULL_AST
 import io.joern.csharpsrc2cpg.astcreation.BuiltinTypes.DotNetTypeMap
 import io.joern.csharpsrc2cpg.datastructures.*
 import io.joern.csharpsrc2cpg.parser.DotNetJsonAst.*
@@ -70,11 +71,9 @@ trait AstForDeclarationsCreator(implicit withSchemaValidation: ValidationMode) {
       typeDeclNode(classDecl, name, fullName, relativeFileName, code(classDecl), inherits = inheritsFromTypeFullName)
     scope.pushNewScope(TypeScope(fullName))
     val modifiers = astForModifiers(classDecl)
-    val members   = astForMembers(classDecl.json(ParserKeys.Members).arr.map(createDotNetNodeInfo).toSeq)
-
-    // TODO: Check if any explicit constructor / static constructor decls exists,
-    //  if it doesn't, need to add in default constructor and static constructor and
-    //  pull all field initializations into them.
+    val members = astForMembers(classDecl.json(ParserKeys.Members).arr.map(createDotNetNodeInfo).toSeq)
+      ++ addConstructorWithFieldInitializationsIfNeeded(fullName)
+    // TODO: do the same for static fields
 
     scope.popScope()
     val typeDeclAst = Ast(typeDecl)
@@ -84,6 +83,50 @@ trait AstForDeclarationsCreator(implicit withSchemaValidation: ValidationMode) {
     Seq(typeDeclAst)
   }
 
+  private def addConstructorWithFieldInitializationsIfNeeded(typeDeclFullName: String): Seq[Ast] = {
+    val dynamicFields = scope.getFieldsInScope.filter(f => !f.isStatic && f.isInitialized)
+    val hasExplicitCtor =
+      scope.tryResolveTypeReference(typeDeclFullName).exists(_.methods.exists(_.name == Defines.ConstructorMethodName))
+    // We should only create the constructor when we are the FULL_AST parseLevel. Otherwise, hasExplicitCtor will
+    // not be accurate.
+    val shouldBuildCtor = dynamicFields.nonEmpty && !hasExplicitCtor && parseLevel == FULL_AST
+
+    if (shouldBuildCtor) {
+      val methodReturn = newMethodReturnNode(BuiltinTypes.Void, None, None, None)
+      val signature    = composeMethodLikeSignature(BuiltinTypes.Void, Seq.empty)
+      val modifiers    = Seq(newModifierNode(ModifierTypes.CONSTRUCTOR), newModifierNode(ModifierTypes.INTERNAL))
+      val name         = Defines.ConstructorMethodName
+      val fullName     = composeMethodFullName(typeDeclFullName, name, signature)
+
+      val body = {
+        scope.pushNewScope(MethodScope(fullName))
+        val fieldInitAssignmentAsts = astVariableDeclarationForInitializedFields(dynamicFields)
+        scope.popScope()
+        Ast(NewBlock().typeFullName(Defines.Any)).withChildren(fieldInitAssignmentAsts)
+      }
+
+      val methodNode_ = NewMethod()
+        .name(name)
+        .fullName(fullName)
+        .signature(signature)
+        .filename(relativeFileName)
+
+      val parameterNodes = Seq(
+        NewMethodParameterIn()
+          .name("this")
+          .code("this")
+          .typeFullName(typeDeclFullName)
+          .evaluationStrategy(EvaluationStrategies.BY_SHARING.name)
+          .isVariadic(false)
+          .index(0)
+      )
+
+      methodAst(methodNode_, parameterNodes.map(Ast(_)), body, methodReturn, modifiers) :: Nil
+    } else {
+      Seq.empty
+    }
+  }
+
   protected def astForRecordDeclaration(recordDecl: DotNetNodeInfo): Seq[Ast] = {
     val name     = nameFromNode(recordDecl)
     val fullName = astFullName(recordDecl)

diff --git a/...ntends/csharpsrc2cpg/src/test/scala/io/joern/csharpsrc2cpg/querying/ast/MemberTests.scala b/...ntends/csharpsrc2cpg/src/test/scala/io/joern/csharpsrc2cpg/querying/ast/MemberTests.scala
@@ -101,8 +101,7 @@ class MemberTests extends CSharpCode2CpgFixture {
       }
     }
 
-    // TODO: Not supported yet.
-    "have a constructor" ignore {
+    "have a constructor" in {
       inside(cpg.typeDecl.nameExact("Car").method.nameExact(Defines.ConstructorMethodName).l) {
         case ctor :: Nil =>
           ctor.fullName shouldBe s"Car.${Defines.ConstructorMethodName}:void()"
@@ -113,12 +112,11 @@ class MemberTests extends CSharpCode2CpgFixture {
       }
     }
 
-    // TODO: Not supported yet.
-    "have the member initialization inside the constructor" ignore {
+    "have the member initialization inside the constructor" in {
       inside(cpg.method.fullNameExact(s"Car.${Defines.ConstructorMethodName}:void()").body.assignment.l) {
         case assignment :: Nil =>
-          assignment.target.code shouldBe "Car.nonInitMaxSpeed"
-          assignment.source.code shouldBe "200"
+          assignment.target.code shouldBe "color"
+          assignment.source.code shouldBe "\"red\""
         case xs =>
           fail(s"Expected single assignment inside the constructor, but got $xs")
       }