feat(cli): prompt for misspelled parameter names (#10350)

* feat(cli): add cliutil/levenshtein package
* feat(cli): attempt to catch misspelled parameter names

cli/cliutil/levenshtein/levenshtein.go

@@ -0,0 +1,99 @@
+package levenshtein
+
+import (
+	"golang.org/x/exp/constraints"
+	"golang.org/x/xerrors"
+)
+
+// Matches returns the closest matches to the needle from the haystack.
+// The maxDistance parameter is the maximum Matches distance to consider.
+// If no matches are found, an empty slice is returned.
+func Matches(needle string, maxDistance int, haystack ...string) (matches []string) {
+	for _, hay := range haystack {
+		if d, err := Distance(needle, hay, maxDistance); err == nil && d <= maxDistance {
+			matches = append(matches, hay)
+		}
+	}
+
+	return matches
+}
+
+var ErrMaxDist = xerrors.New("levenshtein: maxDist exceeded")
+
+// Distance returns the edit distance between a and b using the
+// Wagner-Fischer algorithm.
+// A and B must be less than 255 characters long.
+// maxDist is the maximum distance to consider.
+// A value of -1 for maxDist means no maximum.
+func Distance(a, b string, maxDist int) (int, error) {
+	if len(a) > 255 {
+		return 0, xerrors.Errorf("levenshtein: a must be less than 255 characters long")
+	}
+	if len(b) > 255 {
+		return 0, xerrors.Errorf("levenshtein: b must be less than 255 characters long")
+	}
+	m := uint8(len(a))
+	n := uint8(len(b))
+
+	// Special cases for empty strings
+	if m == 0 {
+		return int(n), nil
+	}
+	if n == 0 {
+		return int(m), nil
+	}
+
+	// Allocate a matrix of size m+1 * n+1
+	d := make([][]uint8, 0)
+	var i, j uint8
+	for i = 0; i < m+1; i++ {
+		di := make([]uint8, n+1)
+		d = append(d, di)
+	}
+
+	// Source prefixes
+	for i = 1; i < m+1; i++ {
+		d[i][0] = i
+	}
+
+	// Target prefixes
+	for j = 1; j < n; j++ {
+		d[0][j] = j // nolint:gosec // this cannot overflow
+	}
+
+	// Compute the distance
+	for j = 0; j < n; j++ {
+		for i = 0; i < m; i++ {
+			var subCost uint8
+			// Equal
+			if a[i] != b[j] {
+				subCost = 1
+			}
+			// Don't forget: matrix is +1 size
+			d[i+1][j+1] = min(
+				d[i][j+1]+1,     // deletion
+				d[i+1][j]+1,     // insertion
+				d[i][j]+subCost, // substitution
+			)
+			// check maxDist on the diagonal
+			if maxDist > -1 && i == j && d[i+1][j+1] > uint8(maxDist) {
+				return int(d[i+1][j+1]), ErrMaxDist
+			}
+		}
+	}
+
+	return int(d[m][n]), nil
+}
+
+func min[T constraints.Ordered](ts ...T) T {
+	if len(ts) == 0 {
+		panic("min: no arguments")
+	}
+	m := ts[0]
+	for _, t := range ts[1:] {
+		if t < m {
+			m = t
+		}
+	}
+	return m
+}

cli/cliutil/levenshtein/levenshtein_test.go

@@ -0,0 +1,194 @@
+package levenshtein_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/cli/cliutil/levenshtein"
+)
+
+func Test_Levenshtein_Matches(t *testing.T) {
+	t.Parallel()
+	for _, tt := range []struct {
+		Name        string
+		Needle      string
+		MaxDistance int
+		Haystack    []string
+		Expected    []string
+	}{
+		{
+			Name:        "empty",
+			Needle:      "",
+			MaxDistance: 0,
+			Haystack:    []string{},
+			Expected:    []string{},
+		},
+		{
+			Name:        "empty haystack",
+			Needle:      "foo",
+			MaxDistance: 0,
+			Haystack:    []string{},
+			Expected:    []string{},
+		},
+		{
+			Name:        "empty needle",
+			Needle:      "",
+			MaxDistance: 0,
+			Haystack:    []string{"foo"},
+			Expected:    []string{},
+		},
+		{
+			Name:        "exact match distance 0",
+			Needle:      "foo",
+			MaxDistance: 0,
+			Haystack:    []string{"foo", "fob"},
+			Expected:    []string{"foo"},
+		},
+		{
+			Name:        "exact match distance 1",
+			Needle:      "foo",
+			MaxDistance: 1,
+			Haystack:    []string{"foo", "bar"},
+			Expected:    []string{"foo"},
+		},
+		{
+			Name:        "not found",
+			Needle:      "foo",
+			MaxDistance: 1,
+			Haystack:    []string{"bar"},
+			Expected:    []string{},
+		},
+		{
+			Name:        "1 deletion",
+			Needle:      "foo",
+			MaxDistance: 1,
+			Haystack:    []string{"bar", "fo"},
+			Expected:    []string{"fo"},
+		},
+		{
+			Name:        "one deletion, two matches",
+			Needle:      "foo",
+			MaxDistance: 1,
+			Haystack:    []string{"bar", "fo", "fou"},
+			Expected:    []string{"fo", "fou"},
+		},
+		{
+			Name:        "one deletion, one addition",
+			Needle:      "foo",
+			MaxDistance: 1,
+			Haystack:    []string{"bar", "fo", "fou", "f"},
+			Expected:    []string{"fo", "fou"},
+		},
+		{
+			Name:        "distance 2",
+			Needle:      "foo",
+			MaxDistance: 2,
+			Haystack:    []string{"bar", "boo", "boof"},
+			Expected:    []string{"boo", "boof"},
+		},
+		{
+			Name:        "longer input",
+			Needle:      "kuberenetes",
+			MaxDistance: 5,
+			Haystack:    []string{"kubernetes", "kubeconfig", "kubectl", "kube"},
+			Expected:    []string{"kubernetes"},
+		},
+	} {
+		tt := tt
+		t.Run(tt.Name, func(t *testing.T) {
+			t.Parallel()
+			actual := levenshtein.Matches(tt.Needle, tt.MaxDistance, tt.Haystack...)
+			require.ElementsMatch(t, tt.Expected, actual)
+		})
+	}
+}
+
+func Test_Levenshtein_Distance(t *testing.T) {
+	t.Parallel()
+
+	for _, tt := range []struct {
+		Name     string
+		A        string
+		B        string
+		MaxDist  int
+		Expected int
+		Error    string
+	}{
+		{
+			Name:     "empty",
+			A:        "",
+			B:        "",
+			MaxDist:  -1,
+			Expected: 0,
+		},
+		{
+			Name:     "a empty",
+			A:        "",
+			B:        "foo",
+			MaxDist:  -1,
+			Expected: 3,
+		},
+		{
+			Name:     "b empty",
+			A:        "foo",
+			B:        "",
+			MaxDist:  -1,
+			Expected: 3,
+		},
+		{
+			Name:     "a is b",
+			A:        "foo",
+			B:        "foo",
+			MaxDist:  -1,
+			Expected: 0,
+		},
+		{
+			Name:     "one addition",
+			A:        "foo",
+			B:        "fooo",
+			MaxDist:  -1,
+			Expected: 1,
+		},
+		{
+			Name:     "one deletion",
+			A:        "fooo",
+			B:        "foo",
+			MaxDist:  -1,
+			Expected: 1,
+		},
+		{
+			Name:     "one substitution",
+			A:        "foo",
+			B:        "fou",
+			MaxDist:  -1,
+			Expected: 1,
+		},
+		{
+			Name:     "different strings entirely",
+			A:        "foo",
+			B:        "bar",
+			MaxDist:  -1,
+			Expected: 3,
+		},
+		{
+			Name:    "different strings, max distance 2",
+			A:       "foo",
+			B:       "bar",
+			MaxDist: 2,
+			Error:   levenshtein.ErrMaxDist.Error(),
+		},
+	} {
+		tt := tt
+		t.Run(tt.Name, func(t *testing.T) {
+			t.Parallel()
+			actual, err := levenshtein.Distance(tt.A, tt.B, tt.MaxDist)
+			if tt.Error == "" {
+				require.NoError(t, err)
+				require.Equal(t, tt.Expected, actual)
+			} else {
+				require.EqualError(t, err, tt.Error)
+			}
+		})
+	}
+}

cli/create_test.go

@@ -391,6 +391,31 @@ func TestCreateWithRichParameters(t *testing.T) {
 		}
 		<-doneChan
 	})
+
+	t.Run("WrongParameterName/DidYouMean", func(t *testing.T) {
+		t.Parallel()
+
+		client := coderdtest.New(t, &coderdtest.Options{IncludeProvisionerDaemon: true})
+		owner := coderdtest.CreateFirstUser(t, client)
+		member, _ := coderdtest.CreateAnotherUser(t, client, owner.OrganizationID)
+		version := coderdtest.CreateTemplateVersion(t, client, owner.OrganizationID, echoResponses)
+		coderdtest.AwaitTemplateVersionJobCompleted(t, client, version.ID)
+
+		template := coderdtest.CreateTemplate(t, client, owner.OrganizationID, version.ID)
+
+		wrongFirstParameterName := "frst-prameter"
+		inv, root := clitest.New(t, "create", "my-workspace", "--template", template.Name,
+			"--parameter", fmt.Sprintf("%s=%s", wrongFirstParameterName, firstParameterValue),
+			"--parameter", fmt.Sprintf("%s=%s", secondParameterName, secondParameterValue),
+			"--parameter", fmt.Sprintf("%s=%s", immutableParameterName, immutableParameterValue))
+		clitest.SetupConfig(t, member, root)
+		pty := ptytest.New(t).Attach(inv)
+		inv.Stdout = pty.Output()
+		inv.Stderr = pty.Output()
+		err := inv.Run()
+		assert.ErrorContains(t, err, "parameter \""+wrongFirstParameterName+"\" is not present in the template")
+		assert.ErrorContains(t, err, "Did you mean: "+firstParameterName)
+	})
 }
 
 func TestCreateValidateRichParameters(t *testing.T) {

cli/parameterresolver.go

@@ -2,14 +2,15 @@ package cli
 
 import (
 	"fmt"
+	"strings"
 
 	"golang.org/x/xerrors"
 
-	"github.com/coder/pretty"
-
 	"github.com/coder/coder/v2/cli/clibase"
 	"github.com/coder/coder/v2/cli/cliui"
+	"github.com/coder/coder/v2/cli/cliutil/levenshtein"
 	"github.com/coder/coder/v2/codersdk"
+	"github.com/coder/pretty"
 )
 
 type WorkspaceCLIAction int
@@ -163,7 +164,7 @@ func (pr *ParameterResolver) verifyConstraints(resolved []codersdk.WorkspaceBuil
 	for _, r := range resolved {
 		tvp := findTemplateVersionParameter(r, templateVersionParameters)
 		if tvp == nil {
-			return xerrors.Errorf("parameter %q is not present in the template", r.Name)
+			return templateVersionParametersNotFound(r.Name, templateVersionParameters)
 		}
 
 		if tvp.Ephemeral && !pr.promptBuildOptions && findWorkspaceBuildParameter(tvp.Name, pr.buildOptions) == nil {
@@ -254,3 +255,19 @@ func isValidTemplateParameterOption(buildParameter codersdk.WorkspaceBuildParame
 	}
 	return false
 }
+
+func templateVersionParametersNotFound(unknown string, params []codersdk.TemplateVersionParameter) error {
+	var sb strings.Builder
+	_, _ = sb.WriteString(fmt.Sprintf("parameter %q is not present in the template.", unknown))
+	// Going with a fairly generous edit distance
+	maxDist := len(unknown) / 2
+	var paramNames []string
+	for _, p := range params {
+		paramNames = append(paramNames, p.Name)
+	}
+	matches := levenshtein.Matches(unknown, maxDist, paramNames...)
+	if len(matches) > 0 {
+		_, _ = sb.WriteString(fmt.Sprintf("\nDid you mean: %s", strings.Join(matches, ", ")))
+	}
+	return xerrors.Errorf(sb.String())
+}