command: Add vars to get command (and refactor it)

internal/command/arguments/get.go

@@ -0,0 +1,54 @@
+// Copyright IBM Corp. 2014, 2026
+// SPDX-License-Identifier: BUSL-1.1
+
+package arguments
+
+import (
+	"github.com/hashicorp/terraform/internal/tfdiags"
+)
+
+// Get represents the command-line arguments for the get command.
+type Get struct {
+	// Vars are the variable-related flags (-var, -var-file).
+	Vars *Vars
+
+	// Update, if true, checks already-downloaded modules for available
+	// updates and installs the newest versions available.
+	Update bool
+
+	// TestDirectory is the Terraform test directory.
+	TestDirectory string
+}
+
+// ParseGet processes CLI arguments, returning a Get value and diagnostics.
+// If errors are encountered, a Get value is still returned representing
+// the best effort interpretation of the arguments.
+func ParseGet(args []string) (*Get, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+	get := &Get{
+		Vars: &Vars{},
+	}
+
+	cmdFlags := extendedFlagSet("get", nil, nil, get.Vars)
+	cmdFlags.BoolVar(&get.Update, "update", false, "update")
+	cmdFlags.StringVar(&get.TestDirectory, "test-directory", "tests", "test-directory")
+
+	if err := cmdFlags.Parse(args); err != nil {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Failed to parse command-line flags",
+			err.Error(),
+		))
+	}
+
+	args = cmdFlags.Args()
+	if len(args) > 0 {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Too many command line arguments",
+			"Expected no positional arguments. Did you mean to use -chdir?",
+		))
+	}
+
+	return get, diags
+}

internal/command/arguments/get_test.go

@@ -0,0 +1,161 @@
+// Copyright IBM Corp. 2014, 2026
+// SPDX-License-Identifier: BUSL-1.1
+
+package arguments
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+
+	"github.com/hashicorp/terraform/internal/tfdiags"
+)
+
+func TestParseGet_valid(t *testing.T) {
+	testCases := map[string]struct {
+		args []string
+		want *Get
+	}{
+		"defaults": {
+			nil,
+			&Get{
+				Vars:          &Vars{},
+				TestDirectory: "tests",
+			},
+		},
+		"update": {
+			[]string{"-update"},
+			&Get{
+				Vars:          &Vars{},
+				Update:        true,
+				TestDirectory: "tests",
+			},
+		},
+		"test-directory": {
+			[]string{"-test-directory", "custom-tests"},
+			&Get{
+				Vars:          &Vars{},
+				TestDirectory: "custom-tests",
+			},
+		},
+		"all options": {
+			[]string{
+				"-update",
+				"-test-directory", "custom-tests",
+			},
+			&Get{
+				Vars:          &Vars{},
+				Update:        true,
+				TestDirectory: "custom-tests",
+			},
+		},
+	}
+
+	cmpOpts := cmp.Options{cmpopts.IgnoreUnexported(Vars{})}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			got, diags := ParseGet(tc.args)
+			if len(diags) > 0 {
+				t.Fatalf("unexpected diags: %v", diags)
+			}
+			if diff := cmp.Diff(tc.want, got, cmpOpts); diff != "" {
+				t.Fatalf("unexpected result\n got: %#v\nwant: %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestParseGet_vars(t *testing.T) {
+	testCases := map[string]struct {
+		args []string
+		want []FlagNameValue
+	}{
+		"var": {
+			args: []string{"-var", "foo=bar"},
+			want: []FlagNameValue{
+				{Name: "-var", Value: "foo=bar"},
+			},
+		},
+		"var-file": {
+			args: []string{"-var-file", "cool.tfvars"},
+			want: []FlagNameValue{
+				{Name: "-var-file", Value: "cool.tfvars"},
+			},
+		},
+		"both": {
+			args: []string{
+				"-var", "foo=bar",
+				"-var-file", "cool.tfvars",
+				"-var", "boop=beep",
+			},
+			want: []FlagNameValue{
+				{Name: "-var", Value: "foo=bar"},
+				{Name: "-var-file", Value: "cool.tfvars"},
+				{Name: "-var", Value: "boop=beep"},
+			},
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			got, diags := ParseGet(tc.args)
+			if len(diags) > 0 {
+				t.Fatalf("unexpected diags: %v", diags)
+			}
+			if vars := got.Vars.All(); !cmp.Equal(vars, tc.want) {
+				t.Fatalf("unexpected vars: %#v", vars)
+			}
+		})
+	}
+}
+
+func TestParseGet_invalid(t *testing.T) {
+	testCases := map[string]struct {
+		args      []string
+		want      *Get
+		wantDiags tfdiags.Diagnostics
+	}{
+		"unknown flag": {
+			[]string{"-boop"},
+			&Get{
+				Vars:          &Vars{},
+				TestDirectory: "tests",
+			},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Failed to parse command-line flags",
+					"flag provided but not defined: -boop",
+				),
+			},
+		},
+		"too many arguments": {
+			[]string{"foo", "bar"},
+			&Get{
+				Vars:          &Vars{},
+				TestDirectory: "tests",
+			},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Too many command line arguments",
+					"Expected no positional arguments. Did you mean to use -chdir?",
+				),
+			},
+		},
+	}
+
+	cmpOpts := cmp.Options{cmpopts.IgnoreUnexported(Vars{})}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			got, gotDiags := ParseGet(tc.args)
+			if diff := cmp.Diff(tc.want, got, cmpOpts); diff != "" {
+				t.Fatalf("unexpected result\n got: %#v\nwant: %#v", got, tc.want)
+			}
+			tfdiags.AssertDiagnosticsMatch(t, gotDiags, tc.wantDiags)
+		})
+	}
+}

internal/command/get.go

@@ -5,9 +5,9 @@ package command
 
 import (
 	"context"
-	"fmt"
 	"strings"
 
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/tfdiags"
 )
 
@@ -18,16 +18,26 @@ type GetCommand struct {
 }
 
 func (c *GetCommand) Run(args []string) int {
-	var update bool
-	var testsDirectory string
-
-	args = c.Meta.process(args)
-	cmdFlags := c.Meta.defaultFlagSet("get")
-	cmdFlags.BoolVar(&update, "update", false, "update")
-	cmdFlags.StringVar(&testsDirectory, "test-directory", "tests", "test-directory")
-	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
-	if err := cmdFlags.Parse(args); err != nil {
-		c.Ui.Error(fmt.Sprintf("Error parsing command-line flags: %s\n", err.Error()))
+	parsedArgs, diags := arguments.ParseGet(c.Meta.process(args))
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
+		return 1
+	}
+
+	loader, err := c.initConfigLoader()
+	if err != nil {
+		diags = diags.Append(err)
+		c.showDiagnostics(diags)
+		return 1
+	}
+
+	var varDiags tfdiags.Diagnostics
+	c.VariableValues, varDiags = parsedArgs.Vars.CollectValues(func(filename string, src []byte) {
+		loader.Parser().ForceFileSource(filename, src)
+	})
+	diags = diags.Append(varDiags)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 
@@ -35,7 +45,7 @@ func (c *GetCommand) Run(args []string) int {
 	ctx, done := c.InterruptibleContext(c.CommandContext())
 	defer done()
 
-	path, err := ModulePath(cmdFlags.Args())
+	path, err := ModulePath(nil)
 	if err != nil {
 		c.Ui.Error(err.Error())
 		return 1
@@ -43,7 +53,8 @@ func (c *GetCommand) Run(args []string) int {
 
 	path = c.normalizePath(path)
 
-	abort, diags := getModules(ctx, &c.Meta, path, testsDirectory, update)
+	abort, moreDiags := getModules(ctx, &c.Meta, path, parsedArgs.TestDirectory, parsedArgs.Update)
+	diags = diags.Append(moreDiags)
 	c.showDiagnostics(diags)
 	if abort || diags.HasErrors() {
 		return 1
@@ -75,7 +86,16 @@ Options:
 
   -no-color             Disable text coloring in the output.
 
-  -test-directory=path	Set the Terraform test directory, defaults to "tests".
+  -test-directory=path  Set the Terraform test directory, defaults to "tests".
+
+  -var 'foo=bar'        Set a value for one of the input variables in the root
+                        module of the configuration. Use this option more than
+                        once to set more than one variable.
+
+  -var-file=filename    Load variable values from the given file, in addition
+                        to the default files terraform.tfvars and *.auto.tfvars.
+                        Use this option more than once to include more than one
+                        variables file.
 
 `
 	return strings.TrimSpace(helpText)