feat: tiered caching state upgrader

feat: tiered caching state upgrader

Author: vaishakdinesh

internal/services/tiered_cache/migration/v500/handler.go

@@ -0,0 +1,88 @@
+package v500
+
+import (
+	"context"
+
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/resource"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-log/tflog"
+)
+
+// UpgradeFromV0 handles state upgrades from v4 SDKv2 provider (schema_version=0) to v5 (version=500).
+//
+// This performs the transformation from v4 → v5 format:
+// - cache_type="smart" → value="on"
+// - cache_type="off" → value="off"
+// - cache_type="generic" → value="off" (argo_tiered_caching with value="on" is created from config)
+func UpgradeFromV0(ctx context.Context, req resource.UpgradeStateRequest, resp *resource.UpgradeStateResponse) {
+	tflog.Info(ctx, "Upgrading tiered_cache state from v4 SDKv2 provider (schema_version=0)")
+
+	// Parse v4 state using v4 model
+	var v4State SourceTieredCacheModel
+	resp.Diagnostics.Append(req.State.Get(ctx, &v4State)...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	// Transform v4 → v5
+	v5State, transformDiags := Transform(ctx, v4State)
+	resp.Diagnostics.Append(transformDiags...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	// Write transformed state
+	resp.Diagnostics.Append(resp.State.Set(ctx, v5State)...)
+	tflog.Info(ctx, "State upgrade from v4 to v5 completed successfully")
+}
+
+// UpgradeFromV1 handles state upgrades from v5 Plugin Framework provider (version=1) to v5 (version=500).
+//
+// This is a no-op upgrade since the schema is compatible - just bumps the version.
+// This handler is only triggered when TF_MIG_TEST=1 (GetSchemaVersion returns 500).
+func UpgradeFromV1(ctx context.Context, req resource.UpgradeStateRequest, resp *resource.UpgradeStateResponse) {
+	tflog.Info(ctx, "Upgrading tiered_cache state from version=1 to version=500 (no-op)")
+
+	// CRITICAL: For no-op upgrades, copy raw state directly
+	// This preserves all state data without any transformation
+	resp.State.Raw = req.State.Raw
+
+	tflog.Info(ctx, "State version bump from 1 to 500 completed")
+}
+
+// Transform converts source (legacy v4) state to target (current v5) state.
+// This function handles the cache_type to value transformation.
+func Transform(ctx context.Context, source SourceTieredCacheModel) (*TargetTieredCacheModel, diag.Diagnostics) {
+	var diags diag.Diagnostics
+
+	// Transform cache_type to value
+	var newValue string
+	cacheType := source.CacheType.ValueString()
+	switch cacheType {
+	case "smart":
+		newValue = "on"
+	case "off":
+		newValue = "off"
+	case "generic":
+		// generic means argo tiered caching is ON and tiered caching is OFF
+		// tf-migrate creates both cloudflare_tiered_cache (value=off) and cloudflare_argo_tiered_caching (value=on)
+		// The argo_tiered_caching resource will be created on apply from the config (not from state upgrade)
+		newValue = "off"
+	default:
+		// For unknown values (e.g., variable references), preserve as-is
+		// The value will be validated by the schema validator
+		newValue = cacheType
+	}
+
+	// Create the target state
+	target := &TargetTieredCacheModel{
+		ID:         source.ID,
+		ZoneID:     source.ZoneID,
+		Value:      types.StringValue(newValue),
+		Editable:   source.Editable,
+		ModifiedOn: source.ModifiedOn,
+	}
+
+	return target, diags
+}