Tweak OpenAPI spec embedding (again) (#67)

.goreleaser.yml

@@ -3,6 +3,7 @@ env:
 before:
   hooks:
     - go mod download
+    - go generate ./...
 project_name: stripe
 builds:
   - main: ./cmd/stripe/main.go

pkg/spec/spec.go

@@ -1,4 +1,4 @@
-//go:generate go run github.com/shurcooL/vfsgen/cmd/vfsgendev -source="github.com/stripe/stripe-cli/pkg/spec".FS
+//go:generate go run vfsgen.go
 
 package spec
 

pkg/spec/vfsgen.go

@@ -0,0 +1,68 @@
+//+build vfsgen
+
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/shurcooL/vfsgen"
+
+	"github.com/stripe/stripe-cli/pkg/spec"
+)
+
+func main() {
+	// Override all file mod times to be the Unix epoch using modTimeFS.
+	// We do this because vfsgen includes mod times in the output file it
+	// generates, but mod times are not managed by git. As a result, they can
+	// be different depending on the developer's machine. Overriding them to a
+	// fixed value ensures that the generated output will only change when the
+	// contents of the embedded files change.
+	var inputFS http.FileSystem = modTimeFS{
+		fs: spec.FS,
+	}
+	err := vfsgen.Generate(inputFS, vfsgen.Options{
+		PackageName:  "spec",
+		BuildTags:    "!dev",
+		VariableName: "FS",
+	})
+	if err != nil {
+		log.Fatalln(err)
+	}
+}
+
+// modTimeFS is an http.FileSystem wrapper that modifies
+// underlying fs such that all of its file mod times are set to the Unix epoch.
+type modTimeFS struct {
+	fs http.FileSystem
+}
+
+func (fs modTimeFS) Open(name string) (http.File, error) {
+	f, err := fs.fs.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return modTimeFile{f}, nil
+}
+
+type modTimeFile struct {
+	http.File
+}
+
+func (f modTimeFile) Stat() (os.FileInfo, error) {
+	fi, err := f.File.Stat()
+	if err != nil {
+		return nil, err
+	}
+	return modTimeFileInfo{fi}, nil
+}
+
+type modTimeFileInfo struct {
+	os.FileInfo
+}
+
+func (modTimeFileInfo) ModTime() time.Time {
+	return time.Unix(0, 0)
+}