refactor state-pull command argument parsing

internal/command/arguments/state_pull.go

@@ -0,0 +1,32 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package arguments
+
+import (
+	"github.com/hashicorp/terraform/internal/tfdiags"
+)
+
+// StatePull represents the command-line arguments for the state pull command.
+type StatePull struct {
+}
+
+// ParseStatePull processes CLI arguments, returning a StatePull value and
+// diagnostics. If errors are encountered, a StatePull value is still returned
+// representing the best effort interpretation of the arguments.
+func ParseStatePull(args []string) (*StatePull, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+	pull := &StatePull{}
+
+	cmdFlags := defaultFlagSet("state pull")
+
+	if err := cmdFlags.Parse(args); err != nil {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Failed to parse command-line flags",
+			err.Error(),
+		))
+	}
+
+	return pull, diags
+}

internal/command/arguments/state_pull_test.go

@@ -0,0 +1,64 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package arguments
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/internal/tfdiags"
+)
+
+func TestParseStatePull_valid(t *testing.T) {
+	testCases := map[string]struct {
+		args []string
+		want *StatePull
+	}{
+		"defaults": {
+			nil,
+			&StatePull{},
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			got, diags := ParseStatePull(tc.args)
+			if len(diags) > 0 {
+				t.Fatalf("unexpected diags: %v", diags)
+			}
+			if *got != *tc.want {
+				t.Fatalf("unexpected result\n got: %#v\nwant: %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestParseStatePull_invalid(t *testing.T) {
+	testCases := map[string]struct {
+		args      []string
+		want      *StatePull
+		wantDiags tfdiags.Diagnostics
+	}{
+		"unknown flag": {
+			[]string{"-boop"},
+			&StatePull{},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Failed to parse command-line flags",
+					"flag provided but not defined: -boop",
+				),
+			},
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			got, gotDiags := ParseStatePull(tc.args)
+			if *got != *tc.want {
+				t.Fatalf("unexpected result\n got: %#v\nwant: %#v", got, tc.want)
+			}
+			tfdiags.AssertDiagnosticsMatch(t, gotDiags, tc.wantDiags)
+		})
+	}
+}

internal/command/state_pull.go

@@ -21,10 +21,9 @@ type StatePullCommand struct {
 }
 
 func (c *StatePullCommand) Run(args []string) int {
-	args = c.Meta.process(args)
-	cmdFlags := c.Meta.defaultFlagSet("state pull")
-	if err := cmdFlags.Parse(args); err != nil {
-		c.Ui.Error(fmt.Sprintf("Error parsing command-line flags: %s\n", err.Error()))
+	_, diags := arguments.ParseStatePull(c.Meta.process(args))
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}