Java: Add some dispatch examples to the external flow step test.

Author: michaelnebel

java/ql/test/library-tests/dataflow/external-models/C.java

@@ -56,6 +56,24 @@ void fooLibrary() {
     lib.apiStepArgQualGeneratedIgnored(arg1);
   }
 
+  void fooPossibleLibraryDispatch(Library lib) {
+    Object arg1 = new Object();
+
+    lib.id(arg1);
+  }
+
+  void fooExplicitDispatch() {
+    Object arg1 = new Object();
+
+    MyLibrary lib = new MyLibrary();
+
+    lib.id(arg1);
+  }
+
+  void fooGeneric(MyGenericLibrary<String> lib) {
+    lib.get();
+  }
+
   Object stepArgRes(Object x) {
     return null;
   }
@@ -73,4 +91,18 @@ void stepQualArg(Object out) {}
   Object stepArgResGenerated(Object x) {
     return null;
   }
+
+  class MyLibrary extends Library {
+    @Override
+    // Bad implementation of the id function.
+    public Object id(Object x) {
+      return null;
+    }
+  }
+
+  public class MyGenericLibrary<T> {
+    public T get() {
+      return null;
+    }
+  }
 }

java/ql/test/library-tests/dataflow/external-models/steps.ext.yml

@@ -9,11 +9,13 @@ extensions:
       - ["my.qltest", "C", False, "stepQualRes", "()", "", "Argument[this]", "ReturnValue", "taint", "manual"]
       - ["my.qltest", "C", False, "stepQualArg", "(Object)", "", "Argument[this]", "Argument[0]", "taint", "manual"]
       - ["my.qltest", "C", False, "stepArgResGenerated", "(Object)", "", "Argument[0]", "ReturnValue", "taint", "df-generated"]
+      - ["my.qltest", "C$MyGenericLibrary", True, "get", "()", "", "Argument[this]", "ReturnValue", "taint", "df-generated"]
       - ["my.qltest.external", "Library", False, "apiStepArgResGenerated", "(Object)", "", "Argument[0]", "ReturnValue", "taint", "df-generated"]
       - ["my.qltest.external", "Library", False, "apiStepArgResGeneratedIgnored", "(Object,Object)", "", "Argument[0]", "ReturnValue", "taint", "df-generated"]
       - ["my.qltest.external", "Library", False, "apiStepArgResGeneratedIgnored", "(Object,Object)", "", "Argument[1]", "ReturnValue", "taint", "manual"]
       - ["my.qltest.external", "Library", False, "apiStepArgQualGenerated", "(Object)", "", "Argument[0]", "Argument[this]", "taint", "df-generated"]
       - ["my.qltest.external", "Library", False, "apiStepArgQualGeneratedIgnored", "(Object)", "", "Argument[0]", "Argument[this]", "taint", "df-generated"]
+      - ["my.qltest.external", "Library", False, "id", "(Object)", "", "Argument[0]", "ReturnValue", "taint", "df-generated"]
   - addsTo:
       pack: codeql/java-all
       extensible: neutralModel

java/ql/test/library-tests/dataflow/external-models/stubs/Library.java

@@ -16,4 +16,8 @@ public Object apiStepArgQualGenerated(Object x) {
   public Object apiStepArgQualGeneratedIgnored(Object x) {
     return null;
   }
+
+  public Object id(Object x) {
+    return null;
+  }
 }