gopls/internal/settings: add ui.newGoFileHeader option

Toggles auto-completion of copyright comment and package clause for newly created Go files.

Fixes golang/go#74825

Change-Id: Ia08697ab885568a44ffeab5e379c61a57f9ff266
Reviewed-on: https://go-review.googlesource.com/c/tools/+/694275
Reviewed-by: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>
Commit-Queue: Alan Donovan <[email protected]>

Author: skewb1k

gopls/doc/release/v0.21.0.md

@@ -3,6 +3,10 @@ title: "Gopls release v0.21.0 (forthcoming)"
 ---
 
 ## Configuration changes
+
+- The new `newGoFileHeader` option allows toggling automatic insertion of the copyright comment
+  and package declaration in a newly created Go file.
+
 ## Web-based features
 ## Editing features
 ## Analysis features

gopls/doc/settings.md

@@ -261,6 +261,14 @@ By default, all modifiers are enabled.
 
 Default: `{}`.
 
+<a id='newGoFileHeader'></a>
+### `newGoFileHeader bool`
+
+newGoFileHeader enables automatic insertion of the copyright comment
+and package declaration in a newly created Go file.
+
+Default: `true`.
+
 <a id='completion'></a>
 ## Completion
 

gopls/internal/doc/api.json

@@ -2037,6 +2037,20 @@
 				"Hierarchy": "ui",
 				"DeprecationMessage": ""
 			},
+			{
+				"Name": "newGoFileHeader",
+				"Type": "bool",
+				"Doc": "newGoFileHeader enables automatic insertion of the copyright comment\nand package declaration in a newly created Go file.\n",
+				"EnumKeys": {
+					"ValueType": "",
+					"Keys": null
+				},
+				"EnumValues": null,
+				"Default": "true",
+				"Status": "",
+				"Hierarchy": "ui",
+				"DeprecationMessage": ""
+			},
 			{
 				"Name": "local",
 				"Type": "string",

gopls/internal/golang/completion/newfile.go

@@ -16,8 +16,11 @@ import (
 	"golang.org/x/tools/gopls/internal/protocol"
 )
 
-// NewFile returns a document change to complete an empty Go source file.
+// NewFile returns a document change to complete an empty Go source file. Document change may be nil.
 func NewFile(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle) (*protocol.DocumentChange, error) {
+	if !snapshot.Options().NewGoFileHeader {
+		return nil, nil
+	}
 	content, err := fh.Content()
 	if err != nil {
 		return nil, err

gopls/internal/server/workspace.go

@@ -163,7 +163,9 @@ func (s *server) DidCreateFiles(ctx context.Context, params *protocol.CreateFile
 				// any error, including "it's not a new file"
 				continue
 			}
-			allChanges = append(allChanges, *change)
+			if change != nil {
+				allChanges = append(allChanges, *change)
+			}
 		default:
 		}
 	}

gopls/internal/settings/default.go

@@ -132,6 +132,7 @@ func DefaultOptions(overrides ...func(*Options)) *Options {
 						CodeLensVendor:            true,
 						CodeLensRunGovulncheck:    false, // TODO(hyangah): enable
 					},
+					NewGoFileHeader: true,
 				},
 			},
 			InternalOptions: InternalOptions{

gopls/internal/settings/settings.go

@@ -246,6 +246,10 @@ type UIOptions struct {
 	// disabling modifiers by setting each value to false.
 	// By default, all modifiers are enabled.
 	SemanticTokenModifiers map[string]bool `status:"experimental"`
+
+	// NewGoFileHeader enables automatic insertion of the copyright comment
+	// and package declaration in a newly created Go file.
+	NewGoFileHeader bool
 }
 
 // A CodeLensSource identifies an (algorithmic) source of code lenses.
@@ -1287,6 +1291,9 @@ func (o *Options) setOne(name string, value any) (applied []CounterPath, _ error
 	case "semanticTokenModifiers":
 		return setBoolMap(&o.SemanticTokenModifiers, value)
 
+	case "newGoFileHeader":
+		return setBool(&o.NewGoFileHeader, value)
+
 	case "expandWorkspaceToModule":
 		// See golang/go#63536: we can consider deprecating
 		// expandWorkspaceToModule, but probably need to change the default