Allow //exhaustive:ignore on potential enums (#78)

Fixes #76

comment.go

@@ -29,6 +29,9 @@ type directiveSet int64
 func parseDirectives(commentGroups []*ast.CommentGroup) (directiveSet, error) {
 	var out directiveSet
 	for _, commentGroup := range commentGroups {
+		if commentGroup == nil {
+			continue
+		}
 		for _, comment := range commentGroup.List {
 			commentLine := comment.Text
 			if !strings.HasPrefix(commentLine, exhaustiveComment) {

enum.go

@@ -7,6 +7,7 @@ import (
 	"go/types"
 	"strings"
 
+	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/ast/inspector"
 )
 
@@ -63,16 +64,33 @@ func (em *enumMembers) factString() string {
 	return buf.String()
 }
 
-func findEnums(pkgScopeOnly bool, pkg *types.Package, inspect *inspector.Inspector, info *types.Info) map[enumType]enumMembers {
+func findEnums(pass *analysis.Pass, pkgScopeOnly bool, pkg *types.Package, inspect *inspector.Inspector, info *types.Info) map[enumType]enumMembers {
 	result := make(map[enumType]enumMembers)
 
+	ignoredTypes := findIgnoredTypes(pass, inspect, info)
+
 	inspect.Preorder([]ast.Node{&ast.GenDecl{}}, func(n ast.Node) {
 		gen := n.(*ast.GenDecl)
 		if gen.Tok != token.CONST {
 			return
 		}
+
+		if hasIgnoreDecl(pass, gen.Doc) {
+			return
+		}
+
 		for _, s := range gen.Specs {
-			for _, name := range s.(*ast.ValueSpec).Names {
+			s := s.(*ast.ValueSpec)
+			if hasIgnoreDecl(pass, s.Doc) {
+				continue
+			}
+
+			for _, name := range s.Names {
+
+				if _, ignored := ignoredTypes[info.Defs[name].Type()]; ignored {
+					continue
+				}
+
 				enumTyp, memberName, val, ok := possibleEnumMember(name, info)
 				if !ok {
 					continue
@@ -140,6 +158,32 @@ func possibleEnumMember(constName *ast.Ident, info *types.Info) (et enumType, na
 	return enumType{tn}, obj.Name(), determineConstVal(constName, info), true
 }
 
+func findIgnoredTypes(pass *analysis.Pass, inspect *inspector.Inspector, info *types.Info) map[types.Type]struct{} {
+	ignoredTypes := map[types.Type]struct{}{}
+
+	inspect.Preorder([]ast.Node{&ast.GenDecl{}}, func(n ast.Node) {
+		gen := n.(*ast.GenDecl)
+		if gen.Tok != token.TYPE {
+			return
+		}
+
+		doIgnoreDecl := hasIgnoreDecl(pass, gen.Doc)
+
+		for _, s := range gen.Specs {
+			t := s.(*ast.TypeSpec)
+
+			doIgnoreSpec := doIgnoreDecl || hasIgnoreDecl(pass, t.Doc)
+			if !doIgnoreSpec {
+				continue
+			}
+
+			ignoredTypes[info.Defs[t.Name].Type()] = struct{}{}
+		}
+	})
+
+	return ignoredTypes
+}
+
 func determineConstVal(name *ast.Ident, info *types.Info) constantValue {
 	c := info.ObjectOf(name).(*types.Const)
 	return constantValue(c.Val().ExactString())
@@ -157,6 +201,15 @@ func validBasic(basic *types.Basic) bool {
 	return false
 }
 
+func hasIgnoreDecl(pass *analysis.Pass, doc *ast.CommentGroup) bool {
+	dirs, err := parseDirectives([]*ast.CommentGroup{doc})
+	if err != nil {
+		pass.Report(makeInvalidDirectiveDiagnostic(doc, err))
+		return false
+	}
+	return dirs.has(ignoreDirective)
+}
+
 // validNamedBasic returns whether the type t is a named type whose underlying
 // type is a valid basic type to form an enum. A type that passes this check
 // meets the definition of an enum type.

enum_test.go

@@ -96,7 +96,7 @@ func TestFindEnums(t *testing.T) {
 
 	for _, pkgOnly := range [...]bool{false, true} {
 		t.Run(fmt.Sprint("pkgOnly", pkgOnly), func(t *testing.T) {
-			result := findEnums(pkgOnly, testdataEnumPkg.Types, inspect, testdataEnumPkg.TypesInfo)
+			result := findEnums(nil, pkgOnly, testdataEnumPkg.Types, inspect, testdataEnumPkg.TypesInfo)
 			checkEnums(t, transform(result), pkgOnly)
 		})
 	}
@@ -366,6 +366,66 @@ func checkEnums(t *testing.T, got []checkEnum, pkgOnly bool) {
 				`1`: {"Float64B"},
 			},
 		}},
+		{"DeclGroupIgnoredEnum", enumMembers{
+			[]string{"DeclGroupIgnoredMemberC"},
+			map[string]token.Pos{
+				"DeclGroupIgnoredMemberC": 0,
+			},
+			map[string]constantValue{
+				"DeclGroupIgnoredMemberC": `3`,
+			},
+			map[constantValue][]string{
+				`3`: {"DeclGroupIgnoredMemberC"},
+			},
+		}},
+		{"DeclIgnoredEnum", enumMembers{
+			[]string{"DeclIgnoredMemberB"},
+			map[string]token.Pos{
+				"DeclIgnoredMemberB": 0,
+			},
+			map[string]constantValue{
+				"DeclIgnoredMemberB": `2`,
+			},
+			map[constantValue][]string{
+				`2`: {"DeclIgnoredMemberB"},
+			},
+		}},
+		{"DeclTypeInnerNotIgnore", enumMembers{
+			[]string{"DeclTypeInnerNotIgnoreMember"},
+			map[string]token.Pos{
+				"DeclTypeInnerNotIgnoreMember": 0,
+			},
+			map[string]constantValue{
+				"DeclTypeInnerNotIgnoreMember": `5`,
+			},
+			map[constantValue][]string{
+				`5`: {"DeclTypeInnerNotIgnoreMember"},
+			},
+		}},
+		{"DeclTypeIgnoredValue", enumMembers{
+			[]string{"DeclTypeNotIgnoredValue"},
+			map[string]token.Pos{
+				"DeclTypeNotIgnoredValue": 0,
+			},
+			map[string]constantValue{
+				"DeclTypeNotIgnoredValue": `1`,
+			},
+			map[constantValue][]string{
+				`1`: {"DeclTypeNotIgnoredValue"},
+			},
+		}},
+		{"DeclTypePartialIgnore", enumMembers{
+			[]string{"DeclTypePartialIgnoreNotIgnored"},
+			map[string]token.Pos{
+				"DeclTypePartialIgnoreNotIgnored": 0,
+			},
+			map[string]constantValue{
+				"DeclTypePartialIgnoreNotIgnored": `2`,
+			},
+			map[constantValue][]string{
+				`2`: {"DeclTypePartialIgnoreNotIgnored"},
+			},
+		}},
 	}
 
 	for _, c := range wantPkg {

exhaustive.go

@@ -108,7 +108,7 @@ var Analyzer = &analysis.Analyzer{
 func run(pass *analysis.Pass) (interface{}, error) {
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 
-	for typ, members := range findEnums(fPackageScopeOnly, pass.Pkg, inspect, pass.TypesInfo) {
+	for typ, members := range findEnums(pass, fPackageScopeOnly, pass.Pkg, inspect, pass.TypesInfo) {
 		exportFact(pass, typ, members)
 	}
 

testdata/src/enum/enum.go

@@ -86,3 +86,56 @@ const (
 )
 
 func (WithMethod) String() string { return "whatever" }
+
+type DeclGroupIgnoredEnum int // want DeclGroupIgnoredEnum:"^DeclGroupIgnoredMemberC$"
+
+//exhaustive:ignore
+const (
+	DeclGroupIgnoredMemberA DeclGroupIgnoredEnum = 1
+	DeclGroupIgnoredMemberB DeclGroupIgnoredEnum = 2
+)
+
+const DeclGroupIgnoredMemberC DeclGroupIgnoredEnum = 3
+
+type DeclIgnoredEnum int // want DeclIgnoredEnum:"^DeclIgnoredMemberB$"
+
+//exhaustive:ignore
+const DeclIgnoredMemberA DeclIgnoredEnum = 1
+
+const DeclIgnoredMemberB DeclIgnoredEnum = 2
+
+//exhaustive:ignore
+type DeclTypeIgnoredEnum int
+
+const (
+	DeclTypeIgnoredMemberA DeclTypeIgnoredEnum = 1
+	DeclTypeIgnoredMemberB DeclTypeIgnoredEnum = 2
+)
+
+type (
+	//exhaustive:ignore
+	DeclTypeInnerIgnore    int
+	DeclTypeInnerNotIgnore int // want DeclTypeInnerNotIgnore:"^DeclTypeInnerNotIgnoreMember$"
+)
+
+const (
+	DeclTypeInnerIgnoreMemberA   DeclTypeInnerIgnore    = 3
+	DeclTypeInnerIgnoreMemberB   DeclTypeInnerIgnore    = 4
+	DeclTypeInnerNotIgnoreMember DeclTypeInnerNotIgnore = 5
+)
+
+type DeclTypeIgnoredValue int // want DeclTypeIgnoredValue:"^DeclTypeNotIgnoredValue$"
+
+const (
+	DeclTypeNotIgnoredValue DeclTypeIgnoredValue = 1
+	//exhaustive:ignore
+	DeclTypeIsIgnoredValue DeclTypeIgnoredValue = 2
+)
+
+type DeclTypePartialIgnore int // want DeclTypePartialIgnore:"^DeclTypePartialIgnoreNotIgnored$"
+
+const (
+	//exhaustive:ignore
+	DeclTypePartialIgnoreIgnored    DeclTypePartialIgnore = 1
+	DeclTypePartialIgnoreNotIgnored DeclTypePartialIgnore = 2
+)