Prepare Sandwich Hime v1 release candidate source

sando/api_contract_test.go

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package sando
+
+import (
+	"fmt"
+	"go/ast"
+	"go/importer"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"os"
+	"sort"
+	"strings"
+	"testing"
+)
+
+func TestV1PublicAPIContract(t *testing.T) {
+	t.Parallel()
+	entries, err := os.ReadDir(".")
+	if err != nil {
+		t.Fatal(err)
+	}
+	fileSet := token.NewFileSet()
+	var files []*ast.File
+	for _, entry := range entries {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".go") || strings.HasSuffix(entry.Name(), "_test.go") {
+			continue
+		}
+		file, err := parser.ParseFile(fileSet, entry.Name(), nil, 0)
+		if err != nil {
+			t.Fatalf("parse %s: %v", entry.Name(), err)
+		}
+		files = append(files, file)
+	}
+	configuration := types.Config{Importer: importer.Default()}
+	checked, err := configuration.Check("gamertan.com/sandwich-hime/sando", fileSet, files, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	qualifier := func(pkg *types.Package) string {
+		if pkg == nil || pkg.Path() == checked.Path() {
+			return ""
+		}
+		return pkg.Name()
+	}
+	var actual []string
+	for _, name := range checked.Scope().Names() {
+		if !token.IsExported(name) {
+			continue
+		}
+		object := checked.Scope().Lookup(name)
+		switch object := object.(type) {
+		case *types.Const:
+			actual = append(actual, fmt.Sprintf("const %s = %s", object.Name(), object.Val().ExactString()))
+		case *types.TypeName:
+			named, ok := object.Type().(*types.Named)
+			if !ok {
+				actual = append(actual, types.ObjectString(object, qualifier))
+				break
+			}
+			if structure, ok := named.Underlying().(*types.Struct); ok {
+				var fields []string
+				for index := 0; index < structure.NumFields(); index++ {
+					field := structure.Field(index)
+					if field.Exported() {
+						fields = append(fields, field.Name()+" "+types.TypeString(field.Type(), qualifier))
+					}
+				}
+				if len(fields) == 0 {
+					actual = append(actual, "type "+object.Name()+" struct{ /* opaque */ }")
+				} else {
+					actual = append(actual, "type "+object.Name()+" struct{"+strings.Join(fields, "; ")+"}")
+				}
+			} else {
+				actual = append(actual, types.ObjectString(object, qualifier))
+			}
+		default:
+			actual = append(actual, types.ObjectString(object, qualifier))
+		}
+		typeName, ok := object.(*types.TypeName)
+		if !ok {
+			continue
+		}
+		named, ok := typeName.Type().(*types.Named)
+		if !ok {
+			continue
+		}
+		for index := 0; index < named.NumMethods(); index++ {
+			method := named.Method(index)
+			if method.Exported() {
+				actual = append(actual, types.ObjectString(method, qualifier))
+			}
+		}
+	}
+	sort.Strings(actual)
+	got := strings.Join(actual, "\n") + "\n"
+	want, err := os.ReadFile("testdata/public-api-v1.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	want = []byte(strings.TrimPrefix(string(want), "# SPDX-License-Identifier: Apache-2.0\n\n"))
+	if string(want) != got {
+		t.Fatalf("v1 public API drifted\n--- committed contract ---\n%s--- observed API ---\n%s", want, got)
+	}
+}