Allow select cases to be numbers (flutter#116625) (flutter#120847)

(cherry picked from commit 583a812)

Co-authored-by: Tae Hyung Kim <thkim1011@users.noreply.github.com>

Author: AlexV525

packages/flutter_tools/lib/src/localizations/message_parser.dart

@@ -70,6 +70,7 @@ Map<ST, List<List<ST>>> grammar = <ST, List<List<ST>>>{
   ],
   ST.selectPart: <List<ST>>[
     <ST>[ST.identifier, ST.openBrace, ST.message, ST.closeBrace],
+    <ST>[ST.number, ST.openBrace, ST.message, ST.closeBrace],
     <ST>[ST.other, ST.openBrace, ST.message, ST.closeBrace],
   ],
 };
@@ -415,6 +416,7 @@ class Parser {
         case ST.selectParts:
           if (tokens.isNotEmpty && (
             tokens[0].type == ST.identifier ||
+            tokens[0].type == ST.number ||
             tokens[0].type == ST.other
           )) {
             parseAndConstructNode(ST.selectParts, 0);
@@ -425,8 +427,10 @@ class Parser {
         case ST.selectPart:
           if (tokens.isNotEmpty && tokens[0].type == ST.identifier) {
             parseAndConstructNode(ST.selectPart, 0);
-          } else if (tokens.isNotEmpty && tokens[0].type == ST.other) {
+          } else if (tokens.isNotEmpty && tokens[0].type == ST.number) {
             parseAndConstructNode(ST.selectPart, 1);
+          } else if (tokens.isNotEmpty && tokens[0].type == ST.other) {
+            parseAndConstructNode(ST.selectPart, 2);
           } else {
             throw L10nParserException(
               'ICU Syntax Error: Select parts must be of the form "identifier { message }"',
@@ -588,6 +592,10 @@ class Parser {
       checkExtraRules(syntaxTree);
       return syntaxTree;
     } on L10nParserException catch (error) {
+      // For debugging purposes.
+      if (logger == null) {
+        rethrow;
+      }
       logger?.printError(error.toString());
       return Node(ST.empty, 0, value: '');
     }

packages/flutter_tools/test/general.shard/message_parser_test.dart

@@ -519,4 +519,15 @@ void main() {
         contains(expectedError3),
     )));
   });
+
+  testWithoutContext('parser allows select cases with numbers', () {
+    final Node node = Parser('numberSelect', 'app_en.arb', '{ count, select, 0{none} 100{perfect} other{required!} }').parse();
+    final Node selectExpr = node.children[0];
+    final Node selectParts = selectExpr.children[5];
+    final Node selectPart = selectParts.children[0];
+    expect(selectPart.children[0].value, equals('0'));
+    expect(selectPart.children[1].value, equals('{'));
+    expect(selectPart.children[2].type, equals(ST.message));
+    expect(selectPart.children[3].value, equals('}'));
+  });
 }