Remove import_${GOOS}.go before building list of packages

Otherwise, old imoprt_${GOOS}.go entries will never go away

Signed-off-by: Ed Warnicke <[email protected]>

main.go

@@ -59,6 +59,24 @@ func main() {
 		exechelper.WithEnvirons(os.Environ()...),
 		exechelper.WithStderr(os.Stderr),
 	}
+
+	// Extract the GOOS
+	goos, ok := os.LookupEnv("GOOS")
+	if !ok {
+		cmdStr := "go env GOOS"
+		goosBytes, GoosErr := exechelper.Output(cmdStr, options...)
+		if GoosErr != nil {
+			log.Fatalf("error extracting GOOS: %+v", GoosErr)
+		}
+		goos = strings.TrimSpace(string(goosBytes))
+	}
+
+	// Compute the filename, and remove any old one *before* we build up the list of packages we need
+	filename := fmt.Sprintf("imports_%s.go", goos)
+	if err := os.Remove(filename); err != nil && !os.IsNotExist(err) {
+		log.Fatalf("unable to remove %s because %+v", filename, err)
+	}
+
 	// Get the module Path and Dir (example: Path: github.com/foo/bar Dir: /home/bob/git/bar)
 	modBytes, err := exechelper.Output(`go list -m -f '{{printf "%s %s" .Path .Dir}}'`, options...)
 	if err != nil {
@@ -91,29 +109,13 @@ func main() {
 	}
 	sort.Strings(input.Packages)
 
-	// Extract the GOOS
-	goos, ok := os.LookupEnv("GOOS")
-	if !ok {
-		cmdStr := "go env GOOS"
-		options := []*exechelper.Option{
-			exechelper.WithStderr(os.Stderr),
-			exechelper.WithStdout(os.Stdout),
-			exechelper.WithEnvirons(os.Environ()...),
-		}
-		goosBytes, GoosErr := exechelper.Output(cmdStr, options...)
-		if GoosErr != nil {
-			log.Fatalf("error extracting GOOS: %+v", GoosErr)
-		}
-		goos = strings.TrimSpace(string(goosBytes))
-	}
-
 	// Create the template
 	tmpl := template.Must(template.New(fmt.Sprintf("imports_%s.go", goos)).Parse(importsGoTmpl))
 
 	// Create the imports.go file
-	f, err := os.Create(fmt.Sprintf("imports_%s.go", goos))
+	f, err := os.Create(filename)
 	if err != nil {
-		log.Fatalf("error creating file: %q: %+v", fmt.Sprintf("imports_%s.go", goos), err)
+		log.Fatalf("error creating file: %q: %+v", filename, err)
 	}
 	defer func() { _ = f.Close() }()
 	if err := tmpl.Execute(f, input); err != nil {