gopls/internal/settings: remove support for "allowModfileModifications"

That no tests fail when this setting is removed is evidence enough that
it is unsupported. Additionally, this was one of the final pins holding
together some of the unnecessary complexity of the gocommand package,
which subsequent CLs will untangle.

Fixes golang/go#65546

Change-Id: I8efececfd743d898c5f72c6a2d2a416e023ee3bc
Reviewed-on: https://go-review.googlesource.com/c/tools/+/579435
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>

Author: findleyr

gopls/doc/settings.md

@@ -108,15 +108,6 @@ gopls has to do to keep your workspace up to date.
 
 Default: `true`.
 
-#### **allowModfileModifications** *bool*
-
-**This setting is experimental and may be deleted.**
-
-allowModfileModifications disables -mod=readonly, allowing imports from
-out-of-scope modules. This option will eventually be removed.
-
-Default: `false`.
-
 #### **allowImplicitNetworkAccess** *bool*
 
 **This setting is experimental and may be deleted.**

gopls/internal/cache/snapshot.go

@@ -502,7 +502,6 @@ func (s *Snapshot) RunGoModUpdateCommands(ctx context.Context, wd string, run fu
 // TODO(adonovan): simplify cleanup mechanism. It's hard to see, but
 // it used only after call to tempModFile.
 func (s *Snapshot) goCommandInvocation(ctx context.Context, flags InvocationFlags, inv *gocommand.Invocation) (tmpURI protocol.DocumentURI, updatedInv *gocommand.Invocation, cleanup func(), err error) {
-	allowModfileModificationOption := s.Options().AllowModfileModifications
 	allowNetworkOption := s.Options().AllowImplicitNetworkAccess
 
 	// TODO(rfindley): it's not clear that this is doing the right thing.
@@ -555,17 +554,10 @@ func (s *Snapshot) goCommandInvocation(ctx context.Context, flags InvocationFlag
 	// (As noted in various TODOs throughout this function, this is very
 	// confusing and not obviously correct, but tests pass and we will eventually
 	// rewrite this entire function.)
-	if inv.ModFlag == "" {
-		switch mode {
-		case LoadWorkspace, Normal:
-			if allowModfileModificationOption {
-				inv.ModFlag = mutableModFlag
-			}
-		case WriteTemporaryModFile:
-			inv.ModFlag = mutableModFlag
-			// -mod must be readonly when using go.work files - see issue #48941
-			inv.Env = append(inv.Env, "GOWORK=off")
-		}
+	if inv.ModFlag == "" && mode == WriteTemporaryModFile {
+		inv.ModFlag = mutableModFlag
+		// -mod must be readonly when using go.work files - see issue #48941
+		inv.Env = append(inv.Env, "GOWORK=off")
 	}
 
 	// TODO(rfindley): if inv.ModFlag was already set to "mod", we may not have

gopls/internal/settings/api_json.go

@@ -123,10 +123,6 @@ type BuildOptions struct {
 	// gopls has to do to keep your workspace up to date.
 	ExpandWorkspaceToModule bool `status:"experimental"`
 
-	// AllowModfileModifications disables -mod=readonly, allowing imports from
-	// out-of-scope modules. This option will eventually be removed.
-	AllowModfileModifications bool `status:"experimental"`
-
 	// AllowImplicitNetworkAccess disables GOPROXY=off, allowing implicit module
 	// downloads rather than requiring user action. This option will eventually
 	// be removed.
@@ -986,8 +982,7 @@ func (o *Options) set(name string, value interface{}, seen map[string]struct{})
 		result.deprecated("")
 
 	case "allowModfileModifications":
-		result.softErrorf("gopls setting \"allowModfileModifications\" is deprecated.\nPlease comment on https://go.dev/issue/65546 if this impacts your workflow.")
-		result.setBool(&o.AllowModfileModifications)
+		result.deprecated("")
 
 	case "allowImplicitNetworkAccess":
 		result.setBool(&o.AllowImplicitNetworkAccess)