Remove deprecated WaitableWaitHandle::getStackTrace()

WaitableWaitHandle::getStackTrace() is not used anymore. The stack trace
is computed on the PHP side using the provided reflection API.

hphp/idl/asio.idl.json

@@ -398,19 +398,6 @@
                     },
                     "args": [
                     ]
-                },
-                {
-                    "name": "getStackTrace",
-                    "desc": "Get stack trace of this wait handle",
-                    "flags": [
-                        "HasDocComment"
-                    ],
-                    "return": {
-                        "type": "VariantVec",
-                        "desc": "An array of WaitableWaitHandles representing full stack trace, starting with this wait handle"
-                    },
-                    "args": [
-                    ]
                 }
             ],
             "consts": [

hphp/runtime/ext/asio/waitable_wait_handle.cpp

@@ -83,58 +83,6 @@ Array c_WaitableWaitHandle::t_getparents() {
   return result;
 }
 
-Array c_WaitableWaitHandle::t_getstacktrace() {
-  // no parent data available if finished
-  if (isFinished()) {
-    return Array::Create();
-  }
-
-  /**
-   * At this point, we have an unfinished wait handle and by definition, all
-   * recursive parents are unfinished as well. Let's walk thru them up the
-   * stack and populate the output array. One particularly tricky case is to
-   * correctly follow cross-context boundaries. Sometimes, a wait handle
-   * originally created in the parent context gets imported and following
-   * its original parents may skip one or more context boundaries. To avoid
-   * this, only parents from the same context are considered. A condition
-   * where no such parent exists indicates a wait handle that was join()-ed
-   * from the parent context.
-   */
-  AsioSession* session = AsioSession::Get();
-  Array result = Array::Create(this);
-  c_WaitableWaitHandle* curr = this;
-
-  while (true) {
-    // find parent in the same context (context may be null)
-    context_idx_t ctx_idx = curr->getContextIdx();
-    curr = curr->getParentInContext(ctx_idx);
-
-    // continue up the stack within the same context
-    if (curr) {
-      result.append(curr);
-      continue;
-    }
-
-    // the whole dependency chain is outside of context
-    if (!ctx_idx) {
-      return result;
-    }
-
-    // cross the boundary; keep crossing until non-empty context is found
-    do {
-      --ctx_idx;
-      result.append(null_variant);
-    } while (ctx_idx && !(curr = session->getContext(ctx_idx)->getCurrent()));
-
-    // all contexts processed
-    if (!ctx_idx) {
-      return result;
-    }
-
-    result.append(curr);
-  }
-}
-
 c_BlockableWaitHandle* c_WaitableWaitHandle::addParent(c_BlockableWaitHandle* parent) {
   c_BlockableWaitHandle* prev = m_firstParent;
   m_firstParent = parent;
@@ -179,16 +127,6 @@ void c_WaitableWaitHandle::setException(ObjectData* exception) {
   }
 }
 
-c_BlockableWaitHandle* c_WaitableWaitHandle::getParentInContext(context_idx_t ctx_idx) {
-  c_BlockableWaitHandle* parent = m_firstParent;
-
-  while (parent && parent->getContextIdx() != ctx_idx) {
-    parent = parent->getNextParent();
-  }
-
-  return parent;
-}
-
 // throws on context depth level overflows and cross-context cycles
 void c_WaitableWaitHandle::join() {
   AsioSession* session = AsioSession::Get();

hphp/runtime/ext/ext_asio.h

@@ -192,7 +192,6 @@ class c_WaitableWaitHandle : public c_WaitHandle {
   public: int t_getcontextidx();
   public: Object t_getcreator();
   public: Array t_getparents();
-  public: Array t_getstacktrace();
 
 
  public:
@@ -213,7 +212,6 @@ class c_WaitableWaitHandle : public c_WaitHandle {
   bool isInContext() { return getContextIdx(); }
 
   c_BlockableWaitHandle* getFirstParent() { return m_firstParent; }
-  c_BlockableWaitHandle* getParentInContext(context_idx_t ctx_idx);
 
   virtual c_WaitableWaitHandle* getChild();
   bool hasCycle(c_WaitableWaitHandle* start);

hphp/system/class_map.cpp

@@ -24828,11 +24828,6 @@ const char *g_class_map[] = {
   (const char *)0x20 /* KindOfArray */, NULL,
   NULL,
   NULL,
-  (const char *)0x10006040, "getStackTrace", "", (const char*)0, (const char*)0,
-  "/**\n * ( excerpt from\n * http://php.net/manual/en/waitablewaithandle.getstacktrace.php )\n *\n * Get stack trace of this wait handle\n *\n * @return     vector  An array of WaitableWaitHandles representing full\n *                     stack trace, starting with this wait handle\n */",
-  (const char *)0x20 /* KindOfArray */, NULL,
-  NULL,
-  NULL,
   NULL,
   NULL,
   NULL,