bug(indexer): parameter extraction is broken in 5 languages (Ruby, PHP ×2, JavaScript, C++) — functions get no Parameter nodes #1527

Collected from a parser audit; these all break parameter extraction, so the affected functions get no Parameter nodes and no HAS_PARAMETER edges. Filing together because they share one root theme and one test surface. All reproduced.

(The Python case is separate and larger — see the annotated-parameter issue filed alongside this.)

1. Ruby — args is always [] for every method

tools/languages/ruby.py:183-191. _parse_method_parameters scans method_node.children for identifier, but parameters live inside a method_parameters child; the only direct identifier child is the method name, which the code explicitly skips.

def add(a, b)  ->  args: []

No Ruby function anywhere gets parameter edges.

2. PHP — emits parameters, but the indexer reads args

tools/languages/php.py:245. Extraction works; the key is wrong.

public function add(int $x, string $y)
  ->  {"parameters": ["$x", "$y"]}     # no "args" key

graph_builder.py:296 and writer.py:339 both read item.get("args", []), so params_batch stays empty. java.py:360, scala.py:197 and solidity.py:373 all emit both keys — PHP is the outlier.

3. PHP — promoted-constructor and variadic parameters dropped

tools/languages/php.py:225. The guard if "variable_name" in child.type or "simple_parameter" in child.type does not substring-match property_promotion_parameter or variadic_parameter.

__construct(private string $dsn)  ->  parameters: []
all(...$filters)                  ->  parameters: []

Promoted constructors are the standard PHP 8 idiom. Their types also never enter var_type_map, degrading $this->x receiver inference.

4. JavaScript — destructured and rest parameters dropped

tools/languages/javascript.py:351-368. _extract_parameters handles only identifier, assignment_pattern and rest_pattern, and the rest_pattern branch reads a field (argument) that node type does not have. object_pattern and array_pattern are unhandled.

function f(a, {b, c}, [d], ...rest)  ->  args: ["a"]      # 3 of 4 lost
const g = ({x}) => x                 ->  args: []

Destructured props are the dominant React idiom, so function Button({label}) yields no parameters at all.

5. C++ — lambda parameters always empty

tools/languages/cpp.py:452. Lines 448-450 correctly walk lambda_expression → lambda_declarator → parameters, then 452 unconditionally overwrites params_node with lambda_node.child_by_field_name('parameters'), which is None. Even restored, line 461 filters for p.type == 'identifier' over a parameter_list of parameter_declaration nodes.

auto f = [](int a, int b){...}  ->  args: []

Suggested fix

Each is independent and local. A shared regression test asserting "declared parameter count == extracted args count" across one fixture per language would catch all five and prevent recurrence — the current fixtures do not assert on parameter counts.

_{From a parser audit of tools/languages/. All five reproduced by running the parsers directly.}