[IPL-7725] Updating calls to the remote HCP Terraform API to retrieve all variables

 accessible to a workspace. This should include:
 - variables declared in the workspace and not overwritten by organization / project varset variables
 - variables inherited from organization / project varsets and not overwritten by workspace variables

Other changes: Adding mocks for new functions in go-tfe after version upgrade

Author: debrin-og

.changes/v1.13/BUG FIXES-20250618-101456.yaml

@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: Retrieve all workspace variables while doing a `terraform import`, include variables inherited from variable sets but not overwritten by the workspace.
+time: 2025-06-18T10:14:56.994302+05:30
+custom:
+    Issue: "37241"

internal/backend/remote/backend_context.go

@@ -113,7 +113,7 @@ func (b *Remote) LocalRun(op *backendrun.Operation) (*backendrun.LocalRun, state
 			log.Printf("[TRACE] skipping retrieving variables from workspace %s/%s (%s), workspace is in Local Execution mode", remoteWorkspaceName, b.organization, remoteWorkspaceID)
 		} else {
 			log.Printf("[TRACE] backend/remote: retrieving variables from workspace %s/%s (%s)", remoteWorkspaceName, b.organization, remoteWorkspaceID)
-			tfeVariables, err := b.client.Variables.List(context.Background(), remoteWorkspaceID, nil)
+			tfeVariables, err := b.client.Variables.ListAll(context.Background(), remoteWorkspaceID, nil)
 			if err != nil && err != tfe.ErrResourceNotFound {
 				diags = diags.Append(fmt.Errorf("error loading variables: %w", err))
 				return nil, nil, diags

internal/cloud/backend_context.go

@@ -111,7 +111,7 @@ func (b *Cloud) LocalRun(op *backendrun.Operation) (*backendrun.LocalRun, statem
 			log.Printf("[TRACE] skipping retrieving variables from workspace %s/%s (%s), workspace is in Local Execution mode", remoteWorkspaceName, b.Organization, remoteWorkspaceID)
 		} else {
 			log.Printf("[TRACE] cloud: retrieving variables from workspace %s/%s (%s)", remoteWorkspaceName, b.Organization, remoteWorkspaceID)
-			tfeVariables, err := b.client.Variables.List(context.Background(), remoteWorkspaceID, nil)
+			tfeVariables, err := b.client.Variables.ListAll(context.Background(), remoteWorkspaceID, nil)
 			if err != nil && err != tfe.ErrResourceNotFound {
 				diags = diags.Append(fmt.Errorf("error loading variables: %w", err))
 				return nil, nil, diags

internal/cloud/tfe_client_mock.go

@@ -1112,6 +1112,11 @@ func newMockRegistryModules(client *MockClient) *MockRegistryModules {
 	}
 }
 
+func (m *MockRegistryModules) ReadTerraformRegistryModule(ctx context.Context, moduleID tfe.RegistryModuleID, version string) (*tfe.TerraformRegistryModule, error) {
+	// TODO implement me
+	panic("implement me")
+}
+
 func (m *MockRegistryModules) List(ctx context.Context, organization string, options *tfe.RegistryModuleListOptions) (*tfe.RegistryModuleList, error) {
 	//TODO implement me
 	panic("implement me")
@@ -1235,6 +1240,11 @@ func newMockRuns(client *MockClient) *MockRuns {
 	}
 }
 
+func (m *MockRuns) ListForOrganization(ctx context.Context, organization string, options *tfe.RunListForOrganizationOptions) (*tfe.OrganizationRunList, error) {
+	// TODO implement me
+	panic("implement me")
+}
+
 func (m *MockRuns) List(ctx context.Context, workspaceID string, options *tfe.RunListOptions) (*tfe.RunList, error) {
 	m.Lock()
 	defer m.Unlock()
@@ -1887,6 +1897,10 @@ func (m *MockVariables) List(ctx context.Context, workspaceID string, options *t
 	return vl, nil
 }
 
+func (m *MockVariables) ListAll(ctx context.Context, workspaceID string, options *tfe.VariableListOptions) (*tfe.VariableList, error) {
+	return m.List(ctx, workspaceID, options)
+}
+
 func (m *MockVariables) Create(ctx context.Context, workspaceID string, options tfe.VariableCreateOptions) (*tfe.Variable, error) {
 	v := &tfe.Variable{
 		ID:       GenerateID("var-"),