Fix edge case in range syntax sugar

Handle special case where the range first character in the range is lowercase and the second is uppercase. This is necessary because uppercase letters come before lowercase letters in the ASCII table, and lets us support ranges like `a-Z`. Signed-off-by: Nick Hale <[email protected]>
acorn-io · Oct 17, 2023 · 23c6764 · 23c6764
1 parent 87ccaa2
commit 23c6764
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Showing 2 changed files with 36 additions and 12 deletions.
diff --git a/pkg/secrets/generate.go b/pkg/secrets/generate.go
@@ -4,6 +4,7 @@ import (
 	"crypto/rand"
 	"math/big"
 	"sort"
+	"unicode"
 
 	"k8s.io/apimachinery/pkg/util/sets"
 )
@@ -48,26 +49,41 @@ func inflateRanges(characterSet string) string {
 	)
 	for i := 0; i < len(runeSet); i++ {
 		cur := runeSet[i]
-		if alphanumeric(cur) {
-			// Alphanumeric character detected
-			if i+2 < len(runeSet) && runeSet[i+1] == '-' && alphanumeric(runeSet[i+2]) {
-				// Range detected, convert to full set of characters
-				start, end := cur, runeSet[i+2]
-				if start > end {
-					// Swap start and end if they're out of order
-					start, end = end, start
+		// Alphanumeric character detected
+		if alphanumeric(cur) && (i+2 < len(runeSet) && runeSet[i+1] == '-' && alphanumeric(runeSet[i+2])) {
+			// Range detected, convert to full set of characters
+			start, end := cur, runeSet[i+2]
+			if start > end {
+				// Swap start and end if they're out of order
+				start, end = end, start
+			}
+
+			// Handle special case where the range first character in the range is lowercase and the second is uppercase.
+			// This is necessary because uppercase letters come before lowercase letters in the ASCII table, and lets
+			// us support ranges like `a-Z`.
+			if unicode.IsLower(end) && unicode.IsUpper(start) {
+				for c := start; c <= 'z'; c++ {
+					if alphanumeric(c) {
+						inflated.Insert(c)
+					}
 				}
 
+				for c := 'A'; c <= end; c++ {
+					if alphanumeric(c) {
+						inflated.Insert(c)
+					}
+				}
+			} else {
 				for c := start; c <= end; c++ {
 					if alphanumeric(c) {
 						inflated.Insert(c)
 					}
 				}
-
-				// Skip the next two characters since we've already processed them
-				i += 2
-				continue
 			}
+
+			// Skip the next two characters since we've already processed them
+			i += 2
+			continue
 		}
 
 		inflated.Insert(cur)

diff --git a/pkg/secrets/generate_test.go b/pkg/secrets/generate_test.go
@@ -43,6 +43,14 @@ func TestInflateRanges(t *testing.T) {
 			name: "z-A",
 			want: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
 		},
+		{
+			name: "a-Z",
+			want: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+		},
+		{
+			name: "Z-a",
+			want: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+		},
 		{
 			name: "a-z",
 			want: "abcdefghijklmnopqrstuvwxyz",