Merge pull request github#9398 from github/redsun82/swift-getparent

Swift: simplify `GetImmediateParent.qll`

Author: MathiasVP

swift/codegen/generators/qlgen.py

@@ -119,8 +119,7 @@ def generate(opts, renderer):
     all_imports = ql.ImportList(list(sorted(imports.values())))
     renderer.render(all_imports, include_file)
 
-    renderer.render(ql.GetParentImplementation(classes=classes, imports=[get_import(include_file, opts.swift_dir)]),
-                    out / 'GetImmediateParent.qll')
+    renderer.render(ql.GetParentImplementation(classes), out / 'GetImmediateParent.qll')
 
     renderer.cleanup(existing)
     if opts.ql_format:

swift/codegen/lib/ql.py

@@ -99,4 +99,3 @@ class GetParentImplementation:
     template: ClassVar = 'ql_parent'
 
     classes: List[Class] = field(default_factory=list)
-    imports: List[str] = field(default_factory=list)

swift/codegen/templates/ql_parent.mustache

@@ -1,39 +1,35 @@
 // generated by {{generator}}
 
-{{#imports}}
-import {{.}}
-{{/imports}}
-
-// we are defining this class mainly to leverage existing generation machinery
-// when we generate getters in classes we use the db predicate with `this`. In order to reuse that we need a class here
-// as well
-private class ElementWithChildAccessor extends Element {
-    // why does this look more complicated than it should?
-    // * the none()  simplifies generation, as we can append `or ...` without a special case for the first item
-    // * the `exists` and the `x` variables are there to reuse the same generation done in classes (where the variables
-    //   are used to hide nodes via resolution)
-    Element getAnImmediateChild() {
-      none()
-      {{#classes}}
-      {{#properties}}
-      {{#is_child}}
-      or
-      exists({{type}} {{local_var}}{{#is_repeated}}, int index{{/is_repeated}} | {{tablename}}({{#tableparams}}{{^first}}, {{/first}}{{param}}{{/tableparams}}) and result = {{local_var}})
-      {{/is_child}}
-      {{/properties}}
-      {{/classes}}
-   }
-}
+import codeql.swift.elements.Element
 
 /**
  * Gets any of the "immediate" children of `e`. "Immediate" means not taking into account node resolution: for example
  * if the AST child is the first of a series of conversions that would normally be hidden away, this will select the
  * next conversion down the hidden AST tree instead of the corresponding fully uncoverted node at the bottom.
- * This predicate is mainly intended to be used to test uniqueness of parents.
+ * Outside this module this file is mainly intended to be used to test uniqueness of parents.
  */
 cached
 Element getAnImmediateChild(Element e) {
-   result = e.(ElementWithChildAccessor).getAnImmediateChild()
+  // why does this look more complicated than it should?
+  // * `exists` and the `x` variable are there to reuse the same generation done in classes (where `x` is used to hide
+  //   nodes via resolution)
+  // * none() simplifies generation, as we can append `or ...` without a special case for the first item
+  exists(Element x | result = x and (
+    none()
+    {{#classes}}
+    {{#properties}}
+    {{#is_child}}
+    or
+    {{#is_repeated}}
+    {{tablename}}(e, _, x)
+    {{/is_repeated}}
+    {{^is_repeated}}
+    {{tablename}}(e{{#tableparams}}{{^first}}, {{param}}{{/first}}{{/tableparams}})
+    {{/is_repeated}}
+    {{/is_child}}
+    {{/properties}}
+    {{/classes}}
+  ))
 }
 
 /**

swift/codegen/test/test_qlgen.py

@@ -18,8 +18,8 @@ def run_mock():
 ql_output_path = lambda: paths.swift_dir / "ql/lib/other/path"
 import_file = lambda: stub_path().with_suffix(".qll")
 children_file = lambda: ql_output_path() / "GetImmediateParent.qll"
-stub_import = "stub.path"
-stub_import_prefix = f"{stub_import}."
+stub_import_prefix = "stub.path."
+root_import = stub_import_prefix + "Element"
 gen_import_prefix = "other.path."
 
 
@@ -69,7 +69,7 @@ def generate_classes(opts, renderer):
 def test_empty(opts, input, renderer):
     assert generate(opts, renderer) == {
         import_file(): ql.ImportList(),
-        children_file(): ql.GetParentImplementation(imports=[stub_import]),
+        children_file(): ql.GetParentImplementation(),
     }
 
 
@@ -127,7 +127,6 @@ def test_hierarchy_children(opts, input, renderer):
                  ql.Class(name="D", final=True, bases=["B", "C"],
                           imports=[stub_import_prefix + cls for cls in "BC"]),
                  ],
-        imports=[stub_import],
     )