roachpb: remove SetInner in favor of MustSetInner

As of a recent commit, `ErrorDetail.SetInner` became unused, and
we can switch to a `MustSetInner` pattern for `ErrorDetail`. Since
the codegen involved is shared with {Request,Response}Union, those
lose the `SetInner` setter as well; we were always asserting on
the returned bool there anyway so this isn't changing anything.

Release note: None

pkg/kv/kvclient/kvcoord/txn_interceptor_committer.go

@@ -163,7 +163,7 @@ func (tc *txnCommitter) SendLocked(
 			// Make a copy of the EndTxn, since we're going to change it below to
 			// disable the parallel commit.
 			etCpy := *et
-			ba.Requests[len(ba.Requests)-1].SetInner(&etCpy)
+			ba.Requests[len(ba.Requests)-1].MustSetInner(&etCpy)
 			et = &etCpy
 		}
 	}

pkg/kv/kvclient/kvcoord/txn_interceptor_span_refresher.go

@@ -185,7 +185,7 @@ func (sr *txnSpanRefresher) SendLocked(
 			isReissue := et.DeprecatedCanCommitAtHigherTimestamp
 			if isReissue {
 				etCpy := *et
-				ba.Requests[len(ba.Requests)-1].SetInner(&etCpy)
+				ba.Requests[len(ba.Requests)-1].MustSetInner(&etCpy)
 				et = &etCpy
 			}
 			et.DeprecatedCanCommitAtHigherTimestamp = ba.CanForwardReadTimestamp

pkg/roachpb/api.go

@@ -597,26 +597,6 @@ func (sr *ReverseScanResponse) Verify(req Request) error {
 	return nil
 }
 
-// MustSetInner sets the Request contained in the union. It panics if the
-// request is not recognized by the union type. The RequestUnion is reset
-// before being repopulated.
-func (ru *RequestUnion) MustSetInner(args Request) {
-	ru.Reset()
-	if !ru.SetInner(args) {
-		panic(errors.AssertionFailedf("%T excludes %T", ru, args))
-	}
-}
-
-// MustSetInner sets the Response contained in the union. It panics if the
-// response is not recognized by the union type. The ResponseUnion is reset
-// before being repopulated.
-func (ru *ResponseUnion) MustSetInner(reply Response) {
-	ru.Reset()
-	if !ru.SetInner(reply) {
-		panic(errors.AssertionFailedf("%T excludes %T", ru, reply))
-	}
-}
-
 // Method implements the Request interface.
 func (*GetRequest) Method() Method { return Get }
 

pkg/roachpb/api_test.go

@@ -224,7 +224,7 @@ func TestMustSetInner(t *testing.T) {
 	req := RequestUnion{}
 	res := ResponseUnion{}
 
-	// GetRequest is checked first in the generated code for SetInner.
+	// GetRequest is checked first in the generated code for MustSetInner.
 	req.MustSetInner(&GetRequest{})
 	res.MustSetInner(&GetResponse{})
 	req.MustSetInner(&EndTxnRequest{})

pkg/roachpb/errors.go

@@ -219,6 +219,9 @@ func (e *internalError) Error() string {
 }
 
 // ErrorDetailInterface is an interface for each error detail.
+// These must not be implemented by anything other than our protobuf-backed error details
+// as we rely on a 1:1 correspondence between the interface and what can be stored via
+// `Error.SetDetail`.
 type ErrorDetailInterface interface {
 	error
 	protoutil.Message
@@ -307,12 +310,7 @@ func (e *Error) SetDetail(detail ErrorDetailInterface) {
 	} else {
 		e.TransactionRestart = TransactionRestart_NONE
 	}
-	// If the specific error type exists in the detail union, set it.
-	if !e.Detail.SetInner(detail) {
-		if e.TransactionRestart != TransactionRestart_NONE {
-			panic(errors.AssertionFailedf("transactionRestartError %T must be an ErrorDetail", detail))
-		}
-	}
+	e.Detail.MustSetInner(detail)
 	e.checkTxnStatusValid()
 }
 

pkg/roachpb/gen_batch.go

@@ -108,10 +108,11 @@ func (ru %[1]s) GetInner() %[2]s {
 `)
 }
 
-func genSetInner(w io.Writer, unionName, variantName string, variants []variantInfo) {
+func genMustSetInner(w io.Writer, unionName, variantName string, variants []variantInfo) {
 	fmt.Fprintf(w, `
-// SetInner sets the %[2]s in the union.
-func (ru *%[1]s) SetInner(r %[2]s) bool {
+// MustSetInner sets the %[2]s in the union.
+func (ru *%[1]s) MustSetInner(r %[2]s) {
+  ru.Reset()
 	var union is%[1]s_Value
 	switch t := r.(type) {
 `, unionName, variantName)
@@ -123,10 +124,9 @@ func (ru *%[1]s) SetInner(r %[2]s) bool {
 	}
 
 	fmt.Fprint(w, `	default:
-		return false
+		panic(fmt.Sprintf("unsupported type %T for %T", r, ru))
 	}
 	ru.Value = union
-	return true
 }
 `)
 }
@@ -160,10 +160,10 @@ import (
 	genGetInner(f, "RequestUnion", "Request", reqVariants)
 	genGetInner(f, "ResponseUnion", "Response", resVariants)
 
-	// Generate SetInner methods.
-	genSetInner(f, "ErrorDetail", "error", errVariants)
-	genSetInner(f, "RequestUnion", "Request", reqVariants)
-	genSetInner(f, "ResponseUnion", "Response", resVariants)
+	// Generate MustSetInner methods.
+	genMustSetInner(f, "ErrorDetail", "error", errVariants)
+	genMustSetInner(f, "RequestUnion", "Request", reqVariants)
+	genMustSetInner(f, "ResponseUnion", "Response", resVariants)
 
 	fmt.Fprintf(f, `
 type reqCounts [%d]int32