levenshtein: do not panic

johnstcn · johnstcn · commit f74d0e88a7e6 · 2023-10-27T00:17:33.000-04:00
diff --git a/cli/cliutil/levenshtein/levenshtein.go b/cli/cliutil/levenshtein/levenshtein.go
@@ -10,7 +10,7 @@ import (
 // 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 Distance(needle, hay) <= maxDistance {
+		if d, err := Distance(needle, hay); err == nil && d <= maxDistance {
 			matches = append(matches, hay)
 		}
 	}
@@ -21,19 +21,22 @@ func Matches(needle string, maxDistance int, haystack ...string) (matches []stri
 // Distance returns the edit distance between a and b using the
 // Wagner-Fischer algorithm.
 // A and B must be less than 255 characters long.
-func Distance(a, b string) int {
-	if len(a) > 255 || len(b) > 255 {
-		panic(xerrors.Errorf("levenshtein: strings too long: %q, %q", a, b))
+func Distance(a, b string) (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)
+		return int(n), nil
 	}
 	if n == 0 {
-		return int(m)
+		return int(m), nil
 	}
 
 	// Allocate a matrix of size m+1 * n+1
@@ -71,7 +74,7 @@ func Distance(a, b string) int {
 		}
 	}
 
-	return int(d[m][n])
+	return int(d[m][n]), nil
 }
 
 func min[T constraints.Ordered](ts ...T) T {
diff --git a/cli/cliutil/levenshtein/levenshtein_test.go b/cli/cliutil/levenshtein/levenshtein_test.go
@@ -158,7 +158,8 @@ func Test_Levenshtein_Distance(t *testing.T) {
 		tt := tt
 		t.Run(tt.Name, func(t *testing.T) {
 			t.Parallel()
-			actual := levenshtein.Distance(tt.A, tt.B)
+			actual, err := levenshtein.Distance(tt.A, tt.B)
+			require.NoError(t, err)
 			require.Equal(t, tt.Expected, actual)
 		})
 	}

Original file line number	Diff line number	Diff line change
`@@ -10,7 +10,7 @@ import (`
`10`	`10`	`// If no matches are found, an empty slice is returned.`
`11`	`11`	`func Matches(needle string, maxDistance int, haystack ...string) (matches []string) {`
`12`	`12`	`for _, hay := range haystack {`
`13`		`- if Distance(needle, hay) <= maxDistance {`
	`13`	`+ if d, err := Distance(needle, hay); err == nil && d <= maxDistance {`
`14`	`14`	`matches = append(matches, hay)`
`15`	`15`	`}`
`16`	`16`	`}`
`@@ -21,19 +21,22 @@ func Matches(needle string, maxDistance int, haystack ...string) (matches []stri`
`21`	`21`	`// Distance returns the edit distance between a and b using the`
`22`	`22`	`// Wagner-Fischer algorithm.`
`23`	`23`	`// A and B must be less than 255 characters long.`
`24`		`-func Distance(a, b string) int {`
`25`		`- if len(a) > 255 \|\| len(b) > 255 {`
`26`		`- panic(xerrors.Errorf("levenshtein: strings too long: %q, %q", a, b))`
	`24`	`+func Distance(a, b string) (int, error) {`
	`25`	`+ if len(a) > 255 {`
	`26`	`+ return 0, xerrors.Errorf("levenshtein: a must be less than 255 characters long")`
	`27`	`+ }`
	`28`	`+ if len(b) > 255 {`
	`29`	`+ return 0, xerrors.Errorf("levenshtein: b must be less than 255 characters long")`
`27`	`30`	`}`
`28`	`31`	`m := uint8(len(a))`
`29`	`32`	`n := uint8(len(b))`
`30`	`33`
`31`	`34`	`// Special cases for empty strings`
`32`	`35`	`if m == 0 {`
`33`		`- return int(n)`
	`36`	`+ return int(n), nil`
`34`	`37`	`}`
`35`	`38`	`if n == 0 {`
`36`		`- return int(m)`
	`39`	`+ return int(m), nil`
`37`	`40`	`}`
`38`	`41`
`39`	`42`	`// Allocate a matrix of size m+1 * n+1`
`@@ -71,7 +74,7 @@ func Distance(a, b string) int {`
`71`	`74`	`}`
`72`	`75`	`}`
`73`	`76`
`74`		`- return int(d[m][n])`
	`77`	`+ return int(d[m][n]), nil`
`75`	`78`	`}`
`76`	`79`
`77`	`80`	`func min[T constraints.Ordered](ts ...T) T {`