#2078 - allow nested list indices in expressions

aws · Feb 27, 2025 · 5cf0511 · 5cf0511
1 parent ef40d0c
commit 5cf0511
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Showing 3 changed files with 146 additions and 9 deletions.
diff --git a/.changelog/2cca370d-5f01-451c-979b-b82c55dcf3ec.json b/.changelog/2cca370d-5f01-451c-979b-b82c55dcf3ec.json
@@ -0,0 +1,9 @@
+{
+    "id": "2cca370d-5f01-451c-979b-b82c55dcf3ec",
+    "type": "bugfix",
+    "description": "#2078 - allow nested list indices in expressions",
+    "collapse": true,
+    "modules": [
+        "feature/dynamodb/expression"
+    ]
+}
diff --git a/feature/dynamodb/expression/operand.go b/feature/dynamodb/expression/operand.go
@@ -172,14 +172,17 @@ func (nb NameBuilder) AppendName(field NameBuilder) NameBuilder {
 		lastLeftName := len(nb.names) - 1
 		firstRightName := lastLeftName + 1
 		if v := names[firstRightName]; len(v) > 0 && v[0] == '[' {
-			if end := strings.Index(v, "]"); end != -1 {
-				names[lastLeftName] += v[0 : end+1]
-				names[firstRightName] = v[end+1:]
-				// Remove the name if it is empty after moving the index.
-				if len(names[firstRightName]) == 0 {
-					copy(names[firstRightName:], names[firstRightName+1:])
-					names[len(names)-1] = ""
-					names = names[:len(names)-1]
+			for v != "" {
+				if end := strings.Index(v, "]"); end != -1 || end == len(v)-1 {
+					names[lastLeftName] += v[0 : end+1]
+					names[firstRightName] = v[end+1:]
+					// Remove the name if it is empty after moving the index.
+					if len(names[firstRightName]) == 0 {
+						copy(names[firstRightName:], names[firstRightName+1:])
+						names[len(names)-1] = ""
+						names = names[:len(names)-1]
+					}
+					v = v[end+1:]
 				}
 			}
 		}
@@ -603,10 +606,45 @@ func (nb NameBuilder) BuildOperand() (Operand, error) {
 			return Operand{}, newInvalidParameterError("BuildOperand", "NameBuilder")
 		}
 
-		if idx := strings.Index(word, "]"); idx != -1 && idx != len(word)-1 {
+		numOpenBrackets := strings.Count(word, "[")
+		numCloseBrackets := strings.Count(word, "]")
+
+		// mismatched brackets
+		if numOpenBrackets != numCloseBrackets {
 			return Operand{}, newInvalidParameterError("BuildOperand", "NameBuilder")
 		}
 
+		openPositions := make([]int, 0, numOpenBrackets)
+		closePositions := make([]int, 0, numCloseBrackets)
+
+		for i, char := range word {
+			if char == '[' {
+				openPositions = append(openPositions, i)
+			} else if char == ']' {
+				closePositions = append(closePositions, i)
+			}
+		}
+
+		for idx := range closePositions {
+			openPosition := openPositions[idx]
+			closePosition := closePositions[idx]
+			if openPosition > closePosition {
+				return Operand{}, newInvalidParameterError("BuildOperand", "NameBuilder")
+			}
+
+			part := word[openPosition+1 : closePosition]
+			if len(part) == 0 {
+				return Operand{}, newInvalidParameterError("BuildOperand", "NameBuilder")
+			}
+
+			for _, c := range []byte(part) {
+				c -= '0'
+				if c < 0 || c > 9 {
+					return Operand{}, newInvalidParameterError("BuildOperand", "NameBuilder")
+				}
+			}
+		}
+
 		if word[len(word)-1] == ']' {
 			for j, char := range word {
 				if char == '[' {

diff --git a/feature/dynamodb/expression/operand_test.go b/feature/dynamodb/expression/operand_test.go
@@ -301,6 +301,96 @@ func TestBuildOperand(t *testing.T) {
 			expected: exprNode{},
 			err:      invalidName,
 		},
+		{
+			name:  "no split name name with nested indices",
+			input: NameNoDotSplit("foo.bar[0][0]"),
+			expected: exprNode{
+				names:   []string{"foo.bar"},
+				fmtExpr: "$n[0][0]",
+			},
+		},
+		{
+			name:  "name with nested indices and property",
+			input: Name("foo[1][2].bar"),
+			expected: exprNode{
+				names:   []string{"foo", "bar"},
+				fmtExpr: "$n[1][2].$n",
+			},
+		},
+		{
+			name:  "names with nested indices",
+			input: Name("foo[1][2].bar[3][4]"),
+			expected: exprNode{
+				names:   []string{"foo", "bar"},
+				fmtExpr: "$n[1][2].$n[3][4]",
+			},
+		},
+		{
+			name:  "very log name with nested indices",
+			input: Name("foo[1][2][3][4][5][6][7][8][9][10].bar[11][12][13][14][15][16][17][18]"),
+			expected: exprNode{
+				names:   []string{"foo", "bar"},
+				fmtExpr: "$n[1][2][3][4][5][6][7][8][9][10].$n[11][12][13][14][15][16][17][18]",
+			},
+		},
+		{
+			name:  "very log name with nested indices",
+			input: Name("foo[1][2][3][4][5][6][7][8][9][10].bar[11][12][13][14][15][16][17][18]"),
+			expected: exprNode{
+				names:   []string{"foo", "bar"},
+				fmtExpr: "$n[1][2][3][4][5][6][7][8][9][10].$n[11][12][13][14][15][16][17][18]",
+			},
+		},
+		{
+			name:     "invalid name when bracket is missing",
+			input:    Name("foo["),
+			expected: exprNode{},
+			err:      invalidName,
+		},
+		{
+			name:     "invalid name when bracket is missing",
+			input:    Name("foo]"),
+			expected: exprNode{},
+			err:      invalidName,
+		},
+		{
+			name:     "invalid name when ending with dot",
+			input:    Name("foo."),
+			expected: exprNode{},
+			err:      invalidName,
+		},
+		{
+			name:     "invalid name when alpha index",
+			input:    Name("foo[a]"),
+			expected: exprNode{},
+			err:      invalidName,
+		},
+		{
+			name:     "invalid name when weird brackets",
+			input:    Name("foo]1["),
+			expected: exprNode{},
+			err:      invalidName,
+		},
+		{
+			name: "no split name append name with nested list index",
+			input: NameNoDotSplit("foo.bar").
+				AppendName(Name("foo.bar")).
+				AppendName(Name("[0][1]")).
+				AppendName(Name("abc123")),
+			expected: exprNode{
+				names:   []string{"foo.bar", "foo", "bar", "abc123"},
+				fmtExpr: "$n.$n.$n[0][1].$n",
+			},
+		},
+		{
+			name: "no split name append name with bad nested list index",
+			input: NameNoDotSplit("foo.bar").
+				AppendName(Name("foo.bar")).
+				AppendName(Name("[0][a]")).
+				AppendName(Name("abc123")),
+			expected: exprNode{},
+			err:      invalidName,
+		},
 	}
 
 	for _, c := range cases {