Fixes rjeczalik#44: Fix problem generating an interface in same packa…

…ge as impl

Modify generator to detect if the dependency matches the new interface's
package name and if so, skip adding the dependency (so skip import).

Also, when generating the parameter package names, if the package matches
the new interface's package then make the package blank.

cmd/interfacer/main.go

@@ -58,13 +58,22 @@ func run() error {
 	if *output == "" {
 		return errors.New("empty -o flag value; see -help for details")
 	}
+	packageName := ""
+	interfaceName := ""
+	if i := strings.IndexRune(*as, '.'); i != -1 {
+		packageName = (*as)[:i]
+		interfaceName = (*as)[i+1:]
+	} else {
+		interfaceName = *as
+	}
 	q, err := interfaces.ParseQuery(*query)
 	if err != nil {
 		return err
 	}
 	opts := &interfaces.Options{
-		Query:      q,
-		Unexported: *all,
+		Query:       q,
+		Unexported:  *all,
+		PackageName: packageName,
 	}
 	i, err := interfaces.NewWithOptions(opts)
 	if err != nil {
@@ -75,12 +84,8 @@ func run() error {
 		Deps:      i.Deps(),
 		Interface: i,
 	}
-	if i := strings.IndexRune(*as, '.'); i != -1 {
-		v.PackageName = (*as)[:i]
-		v.InterfaceName = (*as)[i+1:]
-	} else {
-		v.InterfaceName = *as
-	}
+	v.PackageName = packageName
+	v.InterfaceName = interfaceName
 	var buf bytes.Buffer
 	if err := tmpl.Execute(&buf, v); err != nil {
 		return err

interface.go

@@ -57,7 +57,9 @@ func (i Interface) Deps() []string {
 	}
 	deps := make([]string, 0, len(pkgs))
 	for pkg := range pkgs {
-		deps = append(deps, pkg)
+		if pkg != "" {
+			deps = append(deps, pkg)
+		}
 	}
 	sort.Strings(deps)
 	return deps
@@ -133,11 +135,11 @@ func buildInterfaceForPkg(pkg *packages.Package, opts *Options) (Interface, erro
 		}
 		for i := range fn.Ins {
 			fn.Ins[i] = newType(ins.At(i))
-			fixup(&fn.Ins[i], opts.Query)
+			fixup(&fn.Ins[i], opts)
 		}
 		for i := range fn.Outs {
 			fn.Outs[i] = newType(outs.At(i))
-			fixup(&fn.Outs[i], opts.Query)
+			fixup(&fn.Outs[i], opts)
 		}
 		inter = append(inter, fn)
 	}

options.go

@@ -42,9 +42,10 @@ func (q *Query) valid() error {
 
 // Options is used for altering behavior of New() function.
 type Options struct {
-	Query      *Query         // a named type
-	Context    *build.Context // build context; see go/build godoc for details
-	Unexported bool           // whether to include unexported methods
+	Query       *Query         // a named type
+	PackageName string         // name of package to generate interface for
+	Context     *build.Context // build context; see go/build godoc for details
+	Unexported  bool           // whether to include unexported methods
 
 	CSVHeader  []string
 	CSVRecord  []string

type.go

@@ -124,7 +124,10 @@ func (typ *Type) setFromComposite(t compositeType, depth int, orig types.Type) {
 	typ.setFromType(t.Elem(), depth+1, orig)
 }
 
-func fixup(typ *Type, q *Query) {
+func fixup(typ *Type, opts *Options) {
+	query := opts.Query
+	packageName := opts.PackageName
+
 	// Hacky fixup for renaming:
 	//
 	//   GeoAdd(string, []*github.com/go-redis/redis.GeoLocation) *redis.IntCmd
@@ -137,20 +140,25 @@ func fixup(typ *Type, q *Query) {
 
 	// when include other package struct
 	if typ.ImportPath != "" && typ.IsComposite {
-		if typ.ImportPath == q.Package {
+		if typ.ImportPath == query.Package {
 			typ.Name = strings.Replace(typ.Name, typ.ImportPath, typ.Package, -1)
 		}
 
-		if typ.ImportPath != q.Package {
+		if typ.ImportPath != query.Package {
 			pkgIdx := strings.LastIndex(typ.ImportPath, typ.Package)
 			if 0 < pkgIdx {
 				typ.Name = strings.Replace(typ.Name, typ.ImportPath[:pkgIdx], "", -1)
 			}
 		}
 	}
 
-	typ.Name = strings.Replace(typ.Name, q.Package, path.Base(q.Package), -1)
+	typ.Name = strings.Replace(typ.Name, query.Package, path.Base(query.Package), -1)
 	typ.ImportPath = trimVendorPath(typ.ImportPath)
+
+	if typ.Package == packageName {
+		typ.Package = ""
+		typ.ImportPath = ""
+	}
 }
 
 // trimVendorPath removes the vendor dir prefix from a package path.