feat(extraction): PHP string/array callables + Ruby lifecycle-hook symbols (#811)

The last two deferred callback-registration shapes from #756, each scoped
to positions where the reference is trustworthy:

PHP — a string is a callable ONLY in a known callable position:
  - string args of core HOFs (usort, array_map, array_filter,
    call_user_func*, preg_replace_callback, spl_autoload_register,
    set_error_handler, … — PHP_CALLABLE_HOFS): ungated (PHP globals are
    referenced cross-file without imports) + resolution unique-or-drop,
    function-kind only ('Cls::m' strings resolve qualified)
  - array callables anywhere in call args: [$this, 'method'] routes through
    the class-scoped this. resolver (parents included); [Foo::class,
    'method'] resolves qualified
  - strings to arbitrary functions: deliberately nothing

Ruby — hook-DSL symbols name a method of the enclosing class:
  (skip_)?(before|after|around)_* / validate / set_callback /
  helper_method / rescue_from(with:) symbols → class-scoped this.<sym>,
  riding the supertype pass so `before_action :authenticate` in a
  controller resolves to ApplicationController's method. `validates`
  (plural) excluded — its symbols name ATTRIBUTES. Class-body-level hooks
  attribute to the CLASS node (the scoped resolvers now accept class-like
  from-nodes).

Also hardened while validating: the this.X supertype pass is now
NODE-anchored — file-anchored class node → implements/extends edge targets
→ contains-anchored member lookup — replacing the name-keyed
getSupertypes walk, which unioned every same-named class's parents (rails
has a dozen `Engine`s) and produced a cross-class wrong edge.

A/B vs main: WordPress +556 (14/14 sampled genuine — [$this,'m'] wiring,
array_map('absint',…), sodium polyfill call_user_func_array dispatch);
rails/rails +385 after the node-anchored fix (16/16 sampled genuine, incl.
inherited hooks across real extends edges); controls byte-stable
(excalidraw 0-delta, redis identical, typeorm keeps its +4 inherited
getters). The only calls-edge deltas anywhere are pre-existing
minified-bundle resolution jitter (wp-tinymce.js single-letter symbols).

Full suite 1391 passed. EXTRACTION_VERSION 21 → 22 (re-index to benefit).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/extraction/extraction-version.ts

@@ -21,4 +21,4 @@
  * turns the re-index hint into noise — keep it honest (see CLAUDE.md, "Honesty
  * in the product is load-bearing").
  */
-export const EXTRACTION_VERSION = 21;
+export const EXTRACTION_VERSION = 22;

src/extraction/function-ref.ts

@@ -25,9 +25,9 @@
  *
  * Deliberately NOT covered (resolving the *dispatch* — `o->cb(x)` → the
  * registered function — needs data-flow through struct fields; a wrong edge
- * is worse than none): indirect-call resolution, PHP string callables,
- * Ruby bare symbols outside `method(:sym)`, and `obj.method` member values
- * where `obj` isn't `this`/`self`.
+ * is worse than none): indirect-call resolution and `obj.method` member
+ * values where `obj` isn't `this`/`self` (the receiver's type is statically
+ * unknowable without local data-flow).
  */
 
 import type { Node as SyntaxNode } from 'web-tree-sitter';
@@ -45,6 +45,15 @@ export interface FnRefCandidate {
    * C++'s flush policy keys on it.
    */
   explicitRef: boolean;
+  /**
+   * Skip the same-file/import name gate for this candidate. Set for PHP
+   * string callables in known HOF positions: PHP global functions are
+   * referenced cross-file WITHOUT imports (global namespace), so the gate
+   * can't see them — the strong positional prior (a string argument to
+   * `usort`/`array_map`/…) plus resolution's unique-or-drop rule carry the
+   * precision instead.
+   */
+  skipGate?: boolean;
 }
 
 /** How to pull candidate value nodes out of a dispatched container node. */
@@ -252,16 +261,30 @@ const CSHARP_SPEC: FnRefSpec = {
 
 const RUBY_SPEC: FnRefSpec = {
   // Bare identifiers in Ruby args are method CALLS or locals, never function
-  // values — only the `method(:name)` idiom (and `&method(:name)`) qualifies.
+  // values — only the `method(:name)` idiom (and `&method(:name)`) plus
+  // hook-DSL symbols (`before_action :authenticate`) qualify.
   idTypes: new Set<string>(),
   dispatch: new Map<string, CaptureRule>([
     ['argument_list', { mode: 'args' }],
     ['pair', { mode: 'value', field: 'value' }],
   ]),
   layers: new Map<string, string | null>([['block_argument', null]]),
-  special: new Set(['call']),
+  special: new Set(['call', 'simple_symbol']),
 };
 
+/**
+ * Rails/ActiveSupport-style hook DSLs whose symbol arguments name a method of
+ * the enclosing class: lifecycle callbacks (`before_action`, `after_save`,
+ * `around_create`, `skip_before_action`…), `validate :method`, `set_callback`,
+ * `helper_method`, and `rescue_from(..., with: :handler)`. NOT `validates`
+ * (plural) — its symbols name ATTRIBUTES, not methods.
+ */
+const RUBY_HOOK_RE = /^(skip_)?(before|after|around)_[a-z_]+$/;
+const RUBY_HOOK_NAMES = new Set(['validate', 'set_callback', 'helper_method', 'rescue_from']);
+function isRubyHookCall(name: string): boolean {
+  return RUBY_HOOK_RE.test(name) || RUBY_HOOK_NAMES.has(name);
+}
+
 const SWIFT_SPEC: FnRefSpec = {
   idTypes: new Set(['simple_identifier']),
   dispatch: new Map<string, CaptureRule>([
@@ -316,9 +339,39 @@ const PASCAL_SPEC: FnRefSpec = {
 };
 
 /**
- * Capture specs by language. PHP is deliberately absent: its first-class
- * callable `fn(...)` already extracts as a `calls` edge, and string callables
- * (`'fn_name'`) are a precision risk left for a follow-up.
+ * PHP core functions whose string arguments are CALLABLES — the positional
+ * prior that makes a bare string trustworthy as a function reference.
+ * Deliberately core-PHP only; framework registries (WordPress `add_action`)
+ * belong in a frameworks/ resolver if ever added.
+ */
+const PHP_CALLABLE_HOFS = new Set([
+  'array_map', 'array_filter', 'array_walk', 'array_walk_recursive', 'array_reduce',
+  'usort', 'uasort', 'uksort',
+  'array_udiff', 'array_udiff_assoc', 'array_uintersect', 'array_uintersect_assoc',
+  'call_user_func', 'call_user_func_array',
+  'forward_static_call', 'forward_static_call_array',
+  'preg_replace_callback', 'preg_replace_callback_array',
+  'register_shutdown_function', 'register_tick_function',
+  'set_error_handler', 'set_exception_handler', 'spl_autoload_register',
+  'ob_start', 'iterator_apply', 'header_register_callback',
+  'is_callable',
+]);
+
+const PHP_SPEC: FnRefSpec = {
+  // PHP has no bare-identifier function values (the first-class callable
+  // `fn(...)` already extracts as a `calls` edge). What qualifies:
+  //  - a string argument to a known callable-taking core function
+  //    (`usort($a, 'cmp_items')`) — see PHP_CALLABLE_HOFS
+  //  - array callables: `[$this, 'method']` (class-scoped) and
+  //    `[Foo::class, 'method']` (qualified), in any call's arguments
+  idTypes: new Set<string>(),
+  dispatch: new Map<string, CaptureRule>([['arguments', { mode: 'args' }]]),
+  layers: new Map<string, string | null>([['argument', null]]),
+  special: new Set(['encapsed_string', 'string', 'array_creation_expression']),
+};
+
+/**
+ * Capture specs by language.
  */
 export const FN_REF_SPECS: Record<string, FnRefSpec | undefined> = {
   c: cFamilySpec(),
@@ -334,6 +387,7 @@ export const FN_REF_SPECS: Record<string, FnRefSpec | undefined> = {
   java: JAVA_SPEC,
   kotlin: KOTLIN_SPEC,
   csharp: CSHARP_SPEC,
+  php: PHP_SPEC,
   ruby: RUBY_SPEC,
   swift: SWIFT_SPEC,
   scala: SCALA_SPEC,
@@ -441,7 +495,7 @@ export function captureFnRefCandidates(
     // flush, where file scope is known) drops bare ids outside file-scope
     // initializer tables.
     const explicitRef = !spec.idTypes.has(v.type);
-    for (const { name, node } of normalizeValue(v, spec, source, 0)) {
+    for (const { name, node, skipGate } of normalizeValue(v, spec, source, 0)) {
       if (!name || NAME_STOPLIST.has(name)) continue;
       out.push({
         name,
@@ -449,12 +503,20 @@ export function captureFnRefCandidates(
         column: node.startPosition.column,
         mode: rule.mode,
         explicitRef,
+        skipGate,
       });
     }
   }
   return out;
 }
 
+/** One normalized function-value: its name, source node, and gate policy. */
+interface NormalizedRef {
+  name: string;
+  node: SyntaxNode;
+  skipGate?: boolean;
+}
+
 /**
  * Normalize one value expression to zero or more function names. Recursion is
  * bounded (wrapper layers only); anything that isn't a recognized
@@ -465,7 +527,7 @@ function normalizeValue(
   spec: FnRefSpec,
   source: string,
   depth: number
-): Array<{ name: string; node: SyntaxNode }> {
+): NormalizedRef[] {
   if (depth > 4) return [];
   const type = node.type;
 
@@ -497,7 +559,7 @@ function normalizeValue(
       const inner = getChildByField(node, layerField);
       return inner ? normalizeValue(inner, spec, source, depth + 1) : [];
     }
-    const results: Array<{ name: string; node: SyntaxNode }> = [];
+    const results: NormalizedRef[] = [];
     for (let i = 0; i < node.namedChildCount; i++) {
       const child = node.namedChild(i);
       if (child) results.push(...normalizeValue(child, spec, source, depth + 1));
@@ -551,7 +613,7 @@ function normalizeSpecial(
   node: SyntaxNode,
   type: string,
   source: string
-): Array<{ name: string; node: SyntaxNode }> {
+): NormalizedRef[] {
   switch (type) {
     // Java method references. Receiver decides the resolution route (#808):
     //   `this::run0` / `super::close` → `this.<m>` (class-scoped resolver;
@@ -683,7 +745,99 @@ function normalizeSpecial(
       return isThisReceiver ? [{ name: getNodeText(name, source), node: name }] : [];
     }
 
+    // PHP string callable — trustworthy ONLY as an argument to a known
+    // callable-taking core function (`usort($a, 'cmp_items')`). PHP global
+    // functions are referenced cross-file without imports, so these skip the
+    // name gate and rely on resolution's unique-or-drop rule. A
+    // `'Cls::method'` string becomes a qualified candidate.
+    case 'encapsed_string':
+    case 'string': {
+      const callee = phpEnclosingCallName(node);
+      if (!callee || !PHP_CALLABLE_HOFS.has(callee)) return [];
+      const content = phpStringContent(node, source);
+      if (!content) return [];
+      if (/^[A-Za-z_][A-Za-z0-9_]*$/.test(content)) {
+        return [{ name: content, node, skipGate: true }];
+      }
+      if (/^[A-Za-z_][A-Za-z0-9_]*::[A-Za-z_][A-Za-z0-9_]*$/.test(content)) {
+        return [{ name: content, node, skipGate: true }];
+      }
+      return [];
+    }
+
+    // PHP array callables, valid in ANY call's arguments (the shape itself is
+    // unambiguous): `[$this, 'method']` → class-scoped `this.method`;
+    // `[Foo::class, 'method']` → qualified `Foo::method`.
+    case 'array_creation_expression': {
+      if (node.namedChildCount !== 2) return [];
+      const recv = node.namedChild(0)?.namedChild(0);
+      const strEl = node.namedChild(1)?.namedChild(0);
+      if (!recv || !strEl) return [];
+      if (strEl.type !== 'encapsed_string' && strEl.type !== 'string') return [];
+      const member = phpStringContent(strEl, source);
+      if (!member || !/^[A-Za-z_][A-Za-z0-9_]*$/.test(member)) return [];
+      if (recv.type === 'variable_name' && getNodeText(recv, source) === '$this') {
+        return [{ name: `this.${member}`, node: strEl }];
+      }
+      if (recv.type === 'class_constant_access_expression') {
+        const cls = recv.namedChild(0);
+        const kw = recv.namedChild(1);
+        if (cls && kw && getNodeText(kw, source) === 'class') {
+          return [{ name: `${getNodeText(cls, source)}::${member}`, node: strEl }];
+        }
+      }
+      return [];
+    }
+
+    // Ruby hook-DSL symbols (`before_action :authenticate`,
+    // `rescue_from E, with: :render_404`): the symbol names a method of the
+    // ENCLOSING class — route through the class-scoped `this.` resolver
+    // (which also walks superclasses, covering ApplicationController-style
+    // inheritance). Symbols under any other call yield nothing.
+    case 'simple_symbol': {
+      const call = rubyEnclosingCall(node);
+      if (!call) return [];
+      const method = getChildByField(call, 'method');
+      if (!method || !isRubyHookCall(getNodeText(method, source))) return [];
+      const sym = getNodeText(node, source).replace(/^:/, '');
+      if (!/^[A-Za-z_][A-Za-z0-9_?!]*$/.test(sym)) return [];
+      return [{ name: `this.${sym}`, node }];
+    }
+
     default:
       return [];
   }
 }
+
+/** Content of a PHP string literal node (single- or double-quoted). */
+function phpStringContent(node: SyntaxNode, source: string): string | null {
+  for (let i = 0; i < node.namedChildCount; i++) {
+    const child = node.namedChild(i);
+    if (child?.type === 'string_content') return getNodeText(child, source).trim();
+  }
+  return null;
+}
+
+/** The function name of the PHP call whose arguments contain `node`, if any. */
+function phpEnclosingCallName(node: SyntaxNode): string | null {
+  let cur: SyntaxNode | null = node.parent;
+  for (let hops = 0; cur && hops < 4; hops++, cur = cur.parent) {
+    if (cur.type === 'function_call_expression') {
+      const fn = getChildByField(cur, 'function');
+      return fn ? fn.text : null;
+    }
+    if (cur.type === 'member_call_expression' || cur.type === 'scoped_call_expression') {
+      return null; // method calls aren't core HOFs
+    }
+  }
+  return null;
+}
+
+/** The Ruby `call` node whose argument_list (or keyword pair) contains `node`. */
+function rubyEnclosingCall(node: SyntaxNode): SyntaxNode | null {
+  let cur: SyntaxNode | null = node.parent;
+  for (let hops = 0; cur && hops < 4; hops++, cur = cur.parent) {
+    if (cur.type === 'call') return cur;
+  }
+  return null;
+}

src/extraction/tree-sitter.ts

@@ -454,15 +454,18 @@ export class TreeSitterExtractor {
     // segment — the simple name Java/Kotlin code uses in `OtherClass::method`
     // references.
     const SIMPLE_NAME = /^[A-Za-z_$][A-Za-z0-9_$]*$/;
-    const DOTTED_NAME = /^[A-Za-z_$][A-Za-z0-9_$.]*\.([A-Za-z_$][A-Za-z0-9_$]*)$/;
+    // JVM imports are dotted (`com.example.OtherClass`); PHP `use` imports
+    // are backslashed (`App\Services\Mailer`). Both contribute their last
+    // segment — the simple name code uses to reference them.
+    const QUALIFIED_IMPORT = /^[A-Za-z_$][A-Za-z0-9_$.\\]*[.\\]([A-Za-z_$][A-Za-z0-9_$]*)$/;
     const importedNames = new Set<string>();
     for (const r of this.unresolvedReferences) {
       if (r.referenceKind !== 'imports') continue;
       if (SIMPLE_NAME.test(r.referenceName)) {
         importedNames.add(r.referenceName);
       } else {
-        const dotted = r.referenceName.match(DOTTED_NAME);
-        if (dotted) importedNames.add(dotted[1]!);
+        const qualified = r.referenceName.match(QUALIFIED_IMPORT);
+        if (qualified) importedNames.add(qualified[1]!);
       }
     }
 
@@ -497,7 +500,9 @@ export class TreeSitterExtractor {
       //    (constant-expression context — see FnRefSpec.ungatedModes).
       //  - everything else: name ∈ same-file functions/methods ∪ imports.
       if (!c.name.startsWith('this.')) {
-        const skipGate = ungated?.has(c.mode) === true && atFileScope;
+        const skipGate =
+          (ungated?.has(c.mode) === true && atFileScope) ||
+          c.skipGate === true; // PHP HOF-position string callables (see FnRefCandidate.skipGate)
         if (!skipGate) {
           if (c.name.includes('::')) {
             const scopeName = c.name.slice(0, c.name.indexOf('::'));

src/resolution/index.ts

@@ -1212,9 +1212,17 @@ export class ReferenceResolver {
     if (!member) return null;
     const fromNode = this.queries.getNodeById(ref.fromNodeId);
     if (!fromNode) return null;
-    const sep = fromNode.qualifiedName.lastIndexOf('::');
-    if (sep <= 0) return null; // not inside a class scope
-    const classPrefix = fromNode.qualifiedName.slice(0, sep);
+    // A hook declared at class-body level (Ruby `before_action :authenticate`)
+    // attributes to the CLASS node itself — its qualified name IS the scope.
+    // For members, strip the member segment.
+    let classPrefix: string;
+    if (SUPERTYPE_BEARING_KINDS.has(fromNode.kind) || fromNode.kind === 'module') {
+      classPrefix = fromNode.qualifiedName;
+    } else {
+      const sep = fromNode.qualifiedName.lastIndexOf('::');
+      if (sep <= 0) return null; // not inside a class scope
+      classPrefix = fromNode.qualifiedName.slice(0, sep);
+    }
     const candidates = this.context
       .getNodesByQualifiedName(`${classPrefix}::${member}`)
       .filter(
@@ -1260,38 +1268,72 @@ export class ReferenceResolver {
       const member = ref.referenceName.slice('this.'.length);
       const fromNode = this.queries.getNodeById(ref.fromNodeId);
       if (!fromNode || !member) continue;
-      const sep = fromNode.qualifiedName.lastIndexOf('::');
-      if (sep <= 0) continue;
-      const classPrefix = fromNode.qualifiedName.slice(0, sep);
-      const className = classPrefix.includes('::')
-        ? classPrefix.slice(classPrefix.lastIndexOf('::') + 2)
-        : classPrefix;
+      // Class-body-level hooks (Ruby) attribute to the CLASS node itself.
+      let className: string;
+      if (SUPERTYPE_BEARING_KINDS.has(fromNode.kind) || fromNode.kind === 'module') {
+        className = fromNode.name;
+      } else {
+        const sep = fromNode.qualifiedName.lastIndexOf('::');
+        if (sep <= 0) continue;
+        const classPrefix = fromNode.qualifiedName.slice(0, sep);
+        className = classPrefix.includes('::')
+          ? classPrefix.slice(classPrefix.lastIndexOf('::') + 2)
+          : classPrefix;
+      }
 
-      // BFS up the supertype graph by simple name.
-      const seen = new Set<string>([className]);
-      let frontier = this.context.getSupertypes?.(className, ref.language) ?? [];
+      // NODE-anchored BFS up the supertype graph: start from the class node
+      // in the ref's own file (never a same-named class elsewhere — rails has
+      // a dozen `Engine`s), follow implements/extends EDGES to supertype
+      // NODES, and look members up through `contains` edges. No name-based
+      // unions anywhere — a name-keyed getSupertypes('Engine') merged every
+      // Engine's parents and produced a cross-class wrong edge on rails.
+      let frontierNodes = this.context
+        .getNodesByName(className)
+        .filter(
+          (n) =>
+            SUPERTYPE_BEARING_KINDS.has(n.kind) &&
+            n.filePath === ref.filePath
+        );
+      if (frontierNodes.length === 0) {
+        // The class itself may be declared in another file (partial/reopened
+        // classes); fall back to same-family nodes of that name.
+        frontierNodes = this.context
+          .getNodesByName(className)
+          .filter(
+            (n) =>
+              SUPERTYPE_BEARING_KINDS.has(n.kind) &&
+              sameLanguageFamily(n.language, ref.language)
+          );
+      }
+      const seenNodes = new Set<string>(frontierNodes.map((n) => n.id));
       let target: Node | null = null;
-      for (let depth = 0; depth < 5 && frontier.length > 0 && !target; depth++) {
-        const next: string[] = [];
-        for (const superName of frontier) {
-          if (seen.has(superName)) continue;
-          seen.add(superName);
-          const members = this.context
-            .getNodesByName(member)
-            .filter(
-              (n) =>
-                (n.kind === 'function' || n.kind === 'method') &&
-                sameLanguageFamily(n.language, ref.language) &&
-                (n.qualifiedName === `${superName}::${member}` ||
-                  n.qualifiedName.endsWith(`::${superName}::${member}`))
-            );
-          if (members.length > 0) {
-            target = members.reduce((a, b) => (a.startLine <= b.startLine ? a : b));
-            break;
+      for (let depth = 0; depth < 5 && frontierNodes.length > 0 && !target; depth++) {
+        const next: Node[] = [];
+        for (const typeNode of frontierNodes) {
+          for (const edge of this.queries.getOutgoingEdges(typeNode.id, ['implements', 'extends'])) {
+            const superNode = this.queries.getNodeById(edge.target);
+            if (!superNode || seenNodes.has(superNode.id)) continue;
+            seenNodes.add(superNode.id);
+            if (!SUPERTYPE_BEARING_KINDS.has(superNode.kind)) continue;
+            // Member lookup anchored on the supertype's contains edges.
+            for (const c of this.queries.getOutgoingEdges(superNode.id, ['contains'])) {
+              const m = this.queries.getNodeById(c.target);
+              if (
+                m &&
+                m.name === member &&
+                (m.kind === 'function' || m.kind === 'method') &&
+                sameLanguageFamily(m.language, ref.language)
+              ) {
+                target = m;
+                break;
+              }
+            }
+            if (target) break;
+            next.push(superNode);
           }
-          next.push(...(this.context.getSupertypes?.(superName, ref.language) ?? []));
+          if (target) break;
         }
-        frontier = next;
+        frontierNodes = next;
       }
 
       if (target) {

src/resolution/name-matcher.ts

@@ -192,12 +192,15 @@ export function matchFunctionRef(
   // A/B finding; same pattern in vendored docopt.py). Python's `self.m`
   // form keeps method targets via its own capture shape. C++ likewise: a
   // bare identifier can only be a FREE function (member values need
-  // `&Cls::method`). Other languages keep method targets: C# method groups,
-  // Swift/Dart implicit-self, Java/Kotlin method references.
+  // `&Cls::method`). PHP string callables name global FUNCTIONS (methods
+  // need the `[$obj, 'm']` array form, which carries its own shape). Other
+  // languages keep method targets: C# method groups, Swift/Dart
+  // implicit-self, Java/Kotlin method references.
   const bareFnOnly =
     ref.language === 'typescript' || ref.language === 'tsx' ||
     ref.language === 'javascript' || ref.language === 'jsx' ||
-    ref.language === 'cpp' || ref.language === 'python';
+    ref.language === 'cpp' || ref.language === 'python' ||
+    ref.language === 'php';
 
   // Qualified member-pointer (`&Widget::on_click` → "Widget::on_click"):
   // resolve the member ON THAT SCOPE — exempt from bareFnOnly (the `&Cls::m`