feat(generate): Avoid generating empty Go imports (#3135)

* Avoid generating empty Go imports statement

Maybe fixes #3134

* Remove `import ()` from `testdata` golden files

Author: mikeschinkel

examples/jets/postgresql/models.go

@@ -209,6 +209,7 @@ func generate(req *plugin.GenerateRequest, options *opts.Options, enums []Enum,
 		"comment":    sdk.DoubleSlashComment,
 		"escape":     sdk.EscapeBacktick,
 		"imports":    i.Imports,
+		"hasImports": i.HasImports,
 		"hasPrefix":  strings.HasPrefix,
 
 		// These methods are Go specific, they do not belong in the codegen package

internal/codegen/golang/gen.go

@@ -75,6 +75,11 @@ func (i *importer) usesType(typ string) bool {
 	return false
 }
 
+func (i *importer) HasImports(filename string) bool {
+	imports := i.Imports(filename)
+	return len(imports[0]) != 0 || len(imports[1]) != 0
+}
+
 func (i *importer) Imports(filename string) [][]ImportSpec {
 	dbFileName := "db.go"
 	if i.Options.OutputDbFileName != "" {

internal/codegen/golang/imports.go

@@ -9,12 +9,14 @@
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
 
 {{template "dbCode" . }}
 {{end}}
@@ -40,12 +42,14 @@ import (
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
 
 {{template "interfaceCode" . }}
 {{end}}
@@ -69,12 +73,14 @@ import (
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
 
 {{template "modelsCode" . }}
 {{end}}
@@ -167,12 +173,14 @@ type {{.Name}} struct { {{- range .Fields}}
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
 
 {{template "queryCode" . }}
 {{end}}
@@ -196,12 +204,14 @@ import (
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
 
 {{template "copyfromCode" . }}
 {{end}}
@@ -225,12 +235,15 @@ import (
 
 package {{.Package}}
 
+{{ if hasImports .SourceName }}
 import (
 	{{range imports .SourceName}}
 	{{range .}}{{.}}
 	{{end}}
 	{{end}}
 )
+{{end}}
+
 {{template "batchCode" . }}
 {{end}}