toml: fix invalid exception by erroring on duplicate keys in inline table (#26177)

Author: larpon

vlib/toml/parser/parser.v

@@ -818,19 +818,24 @@ pub fn (mut p Parser) inline_table(mut tbl map[string]ast.Value) ! {
 							p.check_immutable(left_most)!
 						}
 					}
+					key_str := key.str()
+					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'inserting @6 "${key_str}" = ${val} into ${ptr_str(t)}')
 					unsafe {
-						util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'inserting @6 "${key}" = ${val} into ${ptr_str(t)}')
-						t[key.str()] = val
+						if _ := t[key_str] {
+							return error(@MOD + '.' + @STRUCT + '.' + @FN +
+								' key "${key_str}" is already initialized with a value. At "${p.tok.kind}" "${p.tok.lit}" in this (excerpt): "...${p.excerpt()}..."')
+						}
+						t[key_str] = val
 					}
 				} else {
 					p.ignore_while(space_formatting)
 					key, val := p.key_value()!
 					key_str := key.str()
+					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'inserting @5 "${key_str}" = ${val} into ${ptr_str(tbl)}')
 					if _ := tbl[key_str] {
 						return error(@MOD + '.' + @STRUCT + '.' + @FN +
 							' key "${key_str}" is already initialized with a value. At "${p.tok.kind}" "${p.tok.lit}" in this (excerpt): "...${p.excerpt()}..."')
 					}
-					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'inserting @5 "${key_str}" = ${val} into ${ptr_str(tbl)}')
 					tbl[key_str] = val
 				}
 				previous_token_was_value = true

vlib/toml/tests/toml_lang_test.v

@@ -24,7 +24,6 @@ const valid_exceptions = [
 // NOTE: entries in this list are tests of invalid TOML that should have the parser fail, but currently does not.
 const invalid_exceptions = [
 	'do_not_remove',
-	'inline-table/duplicate-key-02.toml',
 	'string/multiline-escape-space-02.toml',
 	'string/missing-quotes-array.toml',
 	'table/append-with-dotted-keys-05.toml',