Merge pull request #18448 from github/tausbn/python-add-type-annotation-metrics-query

Python: Add metrics query for type annotations

python/ql/src/Metrics/Internal/TypeAnnotations.ql

@@ -0,0 +1,108 @@
+/**
+ * @name Type metrics
+ * @description Counts of various kinds of type annotations in Python code.
+ * @kind table
+ * @id py/type-metrics
+ */
+
+import python
+
+class BuiltinType extends Name {
+  BuiltinType() { this.getId() in ["int", "float", "str", "bool", "bytes", "None"] }
+}
+
+newtype TAnnotatable =
+  TAnnotatedFunction(FunctionExpr f) { exists(f.getReturns()) } or
+  TAnnotatedParameter(Parameter p) { exists(p.getAnnotation()) } or
+  TAnnotatedAssignment(AnnAssign a) { exists(a.getAnnotation()) }
+
+abstract class Annotatable extends TAnnotatable {
+  string toString() { result = "Annotatable" }
+
+  abstract Expr getAnnotation();
+}
+
+class AnnotatedFunction extends TAnnotatedFunction, Annotatable {
+  FunctionExpr function;
+
+  AnnotatedFunction() { this = TAnnotatedFunction(function) }
+
+  override Expr getAnnotation() { result = function.getReturns() }
+}
+
+class AnnotatedParameter extends TAnnotatedParameter, Annotatable {
+  Parameter parameter;
+
+  AnnotatedParameter() { this = TAnnotatedParameter(parameter) }
+
+  override Expr getAnnotation() { result = parameter.getAnnotation() }
+}
+
+class AnnotatedAssignment extends TAnnotatedAssignment, Annotatable {
+  AnnAssign assignment;
+
+  AnnotatedAssignment() { this = TAnnotatedAssignment(assignment) }
+
+  override Expr getAnnotation() { result = assignment.getAnnotation() }
+}
+
+/** Holds if `e` is a forward declaration of a type. */
+predicate is_forward_declaration(Expr e) { e instanceof StringLiteral }
+
+/** Holds if `e` is a type that may be difficult to analyze. */
+predicate is_complex_type(Expr e) {
+  e instanceof Subscript and not is_optional_type(e)
+  or
+  e instanceof Tuple
+  or
+  e instanceof List
+}
+
+/** Holds if `e` is a type of the form `Optional[...]`. */
+predicate is_optional_type(Subscript e) { e.getObject().(Name).getId() = "Optional" }
+
+/** Holds if `e` is a simple type, that is either an identifier (excluding built-in types) or an attribute of a simple type. */
+predicate is_simple_type(Expr e) {
+  e instanceof Name and not e instanceof BuiltinType
+  or
+  is_simple_type(e.(Attribute).getObject())
+}
+
+/** Holds if `e` is a built-in type. */
+predicate is_builtin_type(Expr e) { e instanceof BuiltinType }
+
+predicate type_count(
+  string kind, int total, int built_in_count, int forward_declaration_count, int simple_type_count,
+  int complex_type_count, int optional_type_count
+) {
+  kind = "Parameter annotation" and
+  total = count(AnnotatedParameter p) and
+  built_in_count = count(AnnotatedParameter p | is_builtin_type(p.getAnnotation())) and
+  forward_declaration_count =
+    count(AnnotatedParameter p | is_forward_declaration(p.getAnnotation())) and
+  simple_type_count = count(AnnotatedParameter p | is_simple_type(p.getAnnotation())) and
+  complex_type_count = count(AnnotatedParameter p | is_complex_type(p.getAnnotation())) and
+  optional_type_count = count(AnnotatedParameter p | is_optional_type(p.getAnnotation()))
+  or
+  kind = "Return type annotation" and
+  total = count(AnnotatedFunction f) and
+  built_in_count = count(AnnotatedFunction f | is_builtin_type(f.getAnnotation())) and
+  forward_declaration_count = count(AnnotatedFunction f | is_forward_declaration(f.getAnnotation())) and
+  simple_type_count = count(AnnotatedFunction f | is_simple_type(f.getAnnotation())) and
+  complex_type_count = count(AnnotatedFunction f | is_complex_type(f.getAnnotation())) and
+  optional_type_count = count(AnnotatedFunction f | is_optional_type(f.getAnnotation()))
+  or
+  kind = "Annotated assignment" and
+  total = count(AnnotatedAssignment a) and
+  built_in_count = count(AnnotatedAssignment a | is_builtin_type(a.getAnnotation())) and
+  forward_declaration_count =
+    count(AnnotatedAssignment a | is_forward_declaration(a.getAnnotation())) and
+  simple_type_count = count(AnnotatedAssignment a | is_simple_type(a.getAnnotation())) and
+  complex_type_count = count(AnnotatedAssignment a | is_complex_type(a.getAnnotation())) and
+  optional_type_count = count(AnnotatedAssignment a | is_optional_type(a.getAnnotation()))
+}
+
+from
+  string message, int total, int built_in, int forward_decl, int simple, int complex, int optional
+where type_count(message, total, built_in, forward_decl, simple, complex, optional)
+select message, total, built_in, forward_decl, simple, complex, optional