Merge "Add type hints to mk2rbc"

mk2rbc/mk2rbc.go

@@ -407,6 +407,8 @@ type parseContext struct {
 	dependentModules map[string]*moduleInfo
 	soongNamespaces  map[string]map[string]bool
 	includeTops      []string
+	typeHints        map[string]starlarkType
+	atTopOfMakefile  bool
 }
 
 func newParseContext(ss *StarlarkScript, nodes []mkparser.Node) *parseContext {
@@ -450,6 +452,8 @@ func newParseContext(ss *StarlarkScript, nodes []mkparser.Node) *parseContext {
 		dependentModules: make(map[string]*moduleInfo),
 		soongNamespaces:  make(map[string]map[string]bool),
 		includeTops:      []string{},
+		typeHints:        make(map[string]starlarkType),
+		atTopOfMakefile:  true,
 	}
 	ctx.pushVarAssignments()
 	for _, item := range predefined {
@@ -1680,7 +1684,8 @@ func (ctx *parseContext) handleSimpleStatement(node mkparser.Node) []starlarkNod
 	// Clear the includeTops after each non-comment statement
 	// so that include annotations placed on certain statements don't apply
 	// globally for the rest of the makefile was well.
-	if _, wasComment := node.(*mkparser.Comment); !wasComment && len(ctx.includeTops) > 0 {
+	if _, wasComment := node.(*mkparser.Comment); !wasComment {
+		ctx.atTopOfMakefile = false
 		ctx.includeTops = []string{}
 	}
 
@@ -1690,6 +1695,12 @@ func (ctx *parseContext) handleSimpleStatement(node mkparser.Node) []starlarkNod
 	return result
 }
 
+// The types allowed in a type_hint
+var typeHintMap = map[string]starlarkType{
+	"string": starlarkTypeString,
+	"list":   starlarkTypeList,
+}
+
 // Processes annotation. An annotation is a comment that starts with #RBC# and provides
 // a conversion hint -- say, where to look for the dynamically calculated inherit/include
 // paths. Returns true if the comment was a successfully-handled annotation.
@@ -1714,6 +1725,35 @@ func (ctx *parseContext) maybeHandleAnnotation(cnode *mkparser.Comment) (starlar
 		}
 		ctx.includeTops = append(ctx.includeTops, p)
 		return nil, true
+	} else if p, ok := maybeTrim(annotation, "type_hint"); ok {
+		// Type hints must come at the beginning the file, to avoid confusion
+		// if a type hint was specified later and thus only takes effect for half
+		// of the file.
+		if !ctx.atTopOfMakefile {
+			return ctx.newBadNode(cnode, "type_hint annotations must come before the first Makefile statement"), true
+		}
+
+		parts := strings.Fields(p)
+		if len(parts) <= 1 {
+			return ctx.newBadNode(cnode, "Invalid type_hint annotation: %s. Must be a variable type followed by a list of variables of that type", p), true
+		}
+
+		var varType starlarkType
+		if varType, ok = typeHintMap[parts[0]]; !ok {
+			varType = starlarkTypeUnknown
+		}
+		if varType == starlarkTypeUnknown {
+			return ctx.newBadNode(cnode, "Invalid type_hint annotation. Only list/string types are accepted, found %s", parts[0]), true
+		}
+
+		for _, name := range parts[1:] {
+			// Don't allow duplicate type hints
+			if _, ok := ctx.typeHints[name]; ok {
+				return ctx.newBadNode(cnode, "Duplicate type hint for variable %s", name), true
+			}
+			ctx.typeHints[name] = varType
+		}
+		return nil, true
 	}
 	return ctx.newBadNode(cnode, "unsupported annotation %s", cnode.Comment), true
 }

mk2rbc/mk2rbc_test.go

@@ -1404,6 +1404,53 @@ def init(g, handle):
     pass
   if int("100%s" % g.get("MY_VAR", "")) >= 10:
     pass
+`,
+	},
+	{
+		desc:   "Type hints",
+		mkname: "product.mk",
+		in: `
+# Test type hints
+#RBC# type_hint list MY_VAR MY_VAR_2
+# Unsupported type
+#RBC# type_hint bool MY_VAR_3
+# Invalid syntax
+#RBC# type_hint list
+# Duplicated variable
+#RBC# type_hint list MY_VAR_2
+#RBC# type_hint list my-local-var-with-dashes
+
+MY_VAR := foo
+MY_VAR_UNHINTED := foo
+
+# Vars set after other statements still get the hint
+MY_VAR_2 := foo
+
+# You can't specify a type hint after the first statement
+#RBC# type_hint list MY_VAR_4
+MY_VAR_4 := foo
+
+my-local-var-with-dashes := foo
+`,
+		expected: `# Test type hints
+# Unsupported type
+load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+  rblf.mk2rbc_error("product.mk:5", "Invalid type_hint annotation. Only list/string types are accepted, found bool")
+  # Invalid syntax
+  rblf.mk2rbc_error("product.mk:7", "Invalid type_hint annotation: list. Must be a variable type followed by a list of variables of that type")
+  # Duplicated variable
+  rblf.mk2rbc_error("product.mk:9", "Duplicate type hint for variable MY_VAR_2")
+  g["MY_VAR"] = ["foo"]
+  g["MY_VAR_UNHINTED"] = "foo"
+  # Vars set after other statements still get the hint
+  g["MY_VAR_2"] = ["foo"]
+  # You can't specify a type hint after the first statement
+  rblf.mk2rbc_error("product.mk:19", "type_hint annotations must come before the first Makefile statement")
+  g["MY_VAR_4"] = "foo"
+  _my_local_var_with_dashes = ["foo"]
 `,
 	},
 }

mk2rbc/variable.go

@@ -291,6 +291,12 @@ var presetVariables = map[string]bool{
 // addVariable returns a variable with a given name. A variable is
 // added if it does not exist yet.
 func (ctx *parseContext) addVariable(name string) variable {
+	// Get the hintType before potentially changing the variable name
+	var hintType starlarkType
+	var ok bool
+	if hintType, ok = ctx.typeHints[name]; !ok {
+		hintType = starlarkTypeUnknown
+	}
 	// Heuristics: if variable's name is all lowercase, consider it local
 	// string variable.
 	isLocalVariable := name == strings.ToLower(name)
@@ -301,8 +307,8 @@ func (ctx *parseContext) addVariable(name string) variable {
 	}
 	v, found := ctx.variables[name]
 	if !found {
-		_, preset := presetVariables[name]
 		if vi, found := KnownVariables[name]; found {
+			_, preset := presetVariables[name]
 			switch vi.class {
 			case VarClassConfig:
 				v = &productConfigVariable{baseVariable{nam: name, typ: vi.valueType, preset: preset}}
@@ -310,10 +316,10 @@ func (ctx *parseContext) addVariable(name string) variable {
 				v = &otherGlobalVariable{baseVariable{nam: name, typ: vi.valueType, preset: preset}}
 			}
 		} else if isLocalVariable {
-			v = &localVariable{baseVariable{nam: name, typ: starlarkTypeUnknown}}
+			v = &localVariable{baseVariable{nam: name, typ: hintType}}
 		} else {
-			vt := starlarkTypeUnknown
-			if strings.HasPrefix(name, "LOCAL_") {
+			vt := hintType
+			if strings.HasPrefix(name, "LOCAL_") && vt == starlarkTypeUnknown {
 				// Heuristics: local variables that contribute to corresponding config variables
 				if cfgVarName, found := localProductConfigVariables[name]; found {
 					vi, found2 := KnownVariables[cfgVarName]