From eb1f1136934d0cadbca3d481be08a9aba17558d7 Mon Sep 17 00:00:00 2001
From: CJ Horton <cjhorton@hashicorp.com>
Date: Thu, 13 May 2021 21:14:15 -0700
Subject: [PATCH] backend/remote: validate API version for refresh and replace

---
 internal/backend/remote/backend_apply.go | 32 ++++++++++++++++++++++++
 internal/backend/remote/backend_plan.go  | 16 ++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/internal/backend/remote/backend_apply.go b/internal/backend/remote/backend_apply.go
index 14be147ba..2ec123d30 100644
--- a/internal/backend/remote/backend_apply.go
+++ b/internal/backend/remote/backend_apply.go
@@ -108,6 +108,38 @@ func (b *Remote) opApply(stopCtx, cancelCtx context.Context, op *backend.Operati
 		}
 	}
 
+	if op.PlanMode == plans.RefreshOnlyMode {
+		desiredAPIVersion, _ := version.NewVersion("2.4")
+
+		if parseErr != nil || currentAPIVersion.LessThan(desiredAPIVersion) {
+			diags = diags.Append(tfdiags.Sourceless(
+				tfdiags.Error,
+				"Refresh-only mode is not supported",
+				fmt.Sprintf(
+					`The host %s does not support -refresh-only mode for `+
+						`remote plans.`,
+					b.hostname,
+				),
+			))
+		}
+	}
+
+	if len(op.ForceReplace) != 0 {
+		desiredAPIVersion, _ := version.NewVersion("2.4")
+
+		if parseErr != nil || currentAPIVersion.LessThan(desiredAPIVersion) {
+			diags = diags.Append(tfdiags.Sourceless(
+				tfdiags.Error,
+				"Planning resource replacements is not supported",
+				fmt.Sprintf(
+					`The host %s does not support the -replace option for `+
+						`remote plans.`,
+					b.hostname,
+				),
+			))
+		}
+	}
+
 	if len(op.Targets) != 0 {
 		desiredAPIVersion, _ := version.NewVersion("2.3")
 
diff --git a/internal/backend/remote/backend_plan.go b/internal/backend/remote/backend_plan.go
index 9f208a7fb..430131050 100644
--- a/internal/backend/remote/backend_plan.go
+++ b/internal/backend/remote/backend_plan.go
@@ -146,6 +146,22 @@ func (b *Remote) opPlan(stopCtx, cancelCtx context.Context, op *backend.Operatio
 		}
 	}
 
+	if op.PlanMode == plans.RefreshOnlyMode {
+		desiredAPIVersion, _ := version.NewVersion("2.4")
+
+		if parseErr != nil || currentAPIVersion.LessThan(desiredAPIVersion) {
+			diags = diags.Append(tfdiags.Sourceless(
+				tfdiags.Error,
+				"Refresh-only mode is not supported",
+				fmt.Sprintf(
+					`The host %s does not support -refresh-only mode for `+
+						`remote plans.`,
+					b.hostname,
+				),
+			))
+		}
+	}
+
 	// Return if there are any errors.
 	if diags.HasErrors() {
 		return nil, diags.Err()