Merge pull request #17357 from smowton/smowton/feature/go-indistinguishable-types

Go: extract and expose struct tags, interface method IDs

Author: smowton

go/downgrades/4bd57e093275e5e892dfb16b55ed4bd76ea662be/go.dbscheme

@@ -0,0 +1,5 @@
+description: Remove component-tags and interface-method-id tables
+compatibility: full
+
+struct_tags.rel: delete
+interface_private_method_ids.rel: delete

go/downgrades/4bd57e093275e5e892dfb16b55ed4bd76ea662be/old.dbscheme

@@ -410,7 +410,7 @@ func AddDefaultSnippet(snippet string) bool {
 
 // PrintDbScheme prints the schema of this database to the writer `w`
 func PrintDbScheme(w io.Writer) {
-	fmt.Fprintf(w, "/** Auto-generated dbscheme; do not edit. */\n\n")
+	fmt.Fprintf(w, "/** Auto-generated dbscheme; do not edit. Run `make gen` in directory `go/` to regenerate. */\n\n")
 	for _, snippet := range defaultSnippets {
 		fmt.Fprintf(w, "%s\n", snippet)
 	}

go/downgrades/4bd57e093275e5e892dfb16b55ed4bd76ea662be/upgrade.properties

@@ -1150,6 +1150,20 @@ var ComponentTypesTable = NewTable("component_types",
 	EntityColumn(TypeType, "tp"),
 ).KeySet("parent", "index")
 
+// StructTagsTable is the table associating struct types with their component types' tags
+var StructTagsTable = NewTable("struct_tags",
+	EntityColumn(StructType, "parent"),
+	IntColumn("index"),
+	StringColumn("tag"),
+).KeySet("parent", "index")
+
+// InterfacePrivateMethodIdsTable is the table associating interface types with the indices and ids of their private methods.
+var InterfacePrivateMethodIdsTable = NewTable("interface_private_method_ids",
+	EntityColumn(InterfaceType, "interface"),
+	IntColumn("index"),
+	StringColumn("id"),
+).KeySet("interface", "index")
+
 // ArrayLengthTable is the table associating array types with their length (represented as a string
 // since Go array lengths are 64-bit and hence do not always fit into a QL integer)
 var ArrayLengthTable = NewTable("array_length",

go/extractor/dbscheme/dbscheme.go

@@ -1624,6 +1624,9 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 					name = ""
 				}
 				extractComponentType(tw, lbl, i, name, field.Type())
+				if tp.Tag(i) != "" {
+					dbscheme.StructTagsTable.Emit(tw, lbl, i, tp.Tag(i))
+				}
 			}
 		case *types.Pointer:
 			kind = dbscheme.PointerType.Index()
@@ -1641,6 +1644,10 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 				extractMethod(tw, meth)
 
 				extractComponentType(tw, lbl, i, meth.Name(), meth.Type())
+
+				if !meth.Exported() {
+					dbscheme.InterfacePrivateMethodIdsTable.Emit(tw, lbl, i, meth.Id())
+				}
 			}
 			for i := 0; i < tp.NumEmbeddeds(); i++ {
 				component := tp.EmbeddedType(i)

go/extractor/dbscheme/tables.go

@@ -0,0 +1,5 @@
+---
+category: minorAnalysis
+---
+* Added member predicates `StructTag.hasOwnFieldWithTag` and `Field.getTag`, which enable CodeQL queries to examine struct field tags.
+* Added member predicate `InterfaceType.hasPrivateMethodWithQualifiedName`, which enables CodeQL queries to distinguish interfaces with matching non-exported method names that are declared in different packages, and are therefore incompatible.

go/extractor/extractor.go

@@ -1,4 +1,4 @@
-/** Auto-generated dbscheme; do not edit. */
+/** Auto-generated dbscheme; do not edit. Run `make gen` in directory `go/` to regenerate. */
 
 
 /** Duplicate code **/
@@ -207,6 +207,12 @@ underlying_type(unique int named: @namedtype ref, int tp: @type ref);
 #keyset[parent, index]
 component_types(int parent: @compositetype ref, int index: int ref, string name: string ref, int tp: @type ref);
 
+#keyset[parent, index]
+struct_tags(int parent: @structtype ref, int index: int ref, string tag: string ref);
+
+#keyset[interface, index]
+interface_private_method_ids(int interface: @interfacetype ref, int index: int ref, string id: string ref);
+
 array_length(unique int tp: @arraytype ref, string len: string ref);
 
 type_objects(unique int tp: @type ref, int object: @object ref);