module T::Private::Methods

def self._check_final_ancestors(target, target_ancestors, source_method_names)
  if !module_with_final?(target)
    return
  end
  # use reverse_each to check farther-up ancestors first, for better error messages. we could avoid this if we were on
  # the version of ruby that adds the optional argument to method_defined? that allows you to exclude ancestors.
  target_ancestors.reverse_each do |ancestor|
    source_method_names.each do |method_name|
      # the usage of method_owner_and_name_to_key(ancestor, method_name) instead of
      # method_to_key(ancestor.instance_method(method_name)) is not (just) an optimization, but also required for
      # correctness, since ancestor.method_defined?(method_name) may return true even if method_name is not defined
      # directly on ancestor but instead an ancestor of ancestor.
      if ancestor.method_defined?(method_name) && final_method?(method_owner_and_name_to_key(ancestor, method_name))
        raise(
          "The method `#{method_name}` on #{ancestor} was declared as final and cannot be " +
          (target == ancestor ? "redefined" : "overridden in #{target}")
        )
      end
    end
  end
end

def self._handle_missing_method_signature(receiver, original_method, callee)
  method_sig = T::Private::Methods.signature_for_method(original_method)
  if !method_sig
    raise "`sig` not present for method `#{callee}` on #{receiver.inspect} but you're trying to run it anyways. " \
      "This should only be executed if you used `alias_method` to grab a handle to a method after `sig`ing it, but that clearly isn't what you are doing. " \
      "Maybe look to see if an exception was thrown in your `sig` lambda or somehow else your `sig` wasn't actually applied to the method."
  end
  if receiver.class <= original_method.owner
    receiving_class = receiver.class
  elsif receiver.singleton_class <= original_method.owner
    receiving_class = receiver.singleton_class
  elsif receiver.is_a?(Module) && receiver <= original_method.owner
    receiving_class = receiver
  else
    raise "#{receiver} is not related to #{original_method} - how did we get here?"
  end
  # Check for a case where `alias` or `alias_method` was called for a
  # method which had already had a `sig` applied. In that case, we want
  # to avoid hitting this slow path again, by moving to a faster validator
  # just like we did or will for the original method.
  #
  # If this isn't an `alias` or `alias_method` case, we're probably in the
  # middle of some metaprogramming using a Method object, e.g. a pattern like
  # `arr.map(&method(:foo))`. There's nothing really we can do to optimize
  # that here.
  receiving_method = receiving_class.instance_method(callee)
  if receiving_method != original_method && receiving_method.original_name == original_method.name
    aliasing_mod = receiving_method.owner
    method_sig = method_sig.as_alias(callee)
    unwrap_method(aliasing_mod, method_sig, original_method)
  end
  method_sig
end

def self._hook_impl(target, target_ancestors, source)
  if !module_with_final?(target) && !module_with_final?(source)
    return
  end
  add_module_with_final(target)
  install_hooks(target)
  _check_final_ancestors(target, target_ancestors - source.ancestors, source.instance_methods)
end

def self._on_method_added(hook_mod, method_name, is_singleton_method: false)
  if T::Private::DeclState.current.skip_on_method_added
    return
  end
  current_declaration = T::Private::DeclState.current.active_declaration
  mod = is_singleton_method ? hook_mod.singleton_class : hook_mod
  if T::Private::Final.final_module?(mod) && (current_declaration.nil? || !current_declaration.final)
    raise "#{mod} was declared as final but its method `#{method_name}` was not declared as final"
  end
  _check_final_ancestors(mod, mod.ancestors, [method_name])
  if current_declaration.nil?
    return
  end
  T::Private::DeclState.current.reset!
  if method_name == :method_added || method_name == :singleton_method_added
    raise(
      "Putting a `sig` on `#{method_name}` is not supported" +
      " (sorbet-runtime uses this method internally to perform `sig` validation logic)"
    )
  end
  original_method = mod.instance_method(method_name)
  sig_block = lambda do
    T::Private::Methods.run_sig(hook_mod, method_name, original_method, current_declaration)
  end
  # Always replace the original method with this wrapper,
  # which is called only on the *first* invocation.
  # This wrapper is very slow, so it will subsequently re-wrap with a much faster wrapper
  # (or unwrap back to the original method).
  new_method = nil
  T::Private::ClassUtils.replace_method(mod, method_name) do |*args, &blk|
    method_sig = T::Private::Methods.maybe_run_sig_block_for_method(new_method)
    method_sig ||= T::Private::Methods._handle_missing_method_signature(
      self,
      original_method,
      __callee__,
    )
    # Should be the same logic as CallValidation.wrap_method_if_needed but we
    # don't want that extra layer of indirection in the callstack
    if method_sig.mode == T::Private::Methods::Modes.abstract
      # We're in an interface method, keep going up the chain
      if defined?(super)
        super(*args, &blk)
      else
        raise NotImplementedError.new("The method `#{method_sig.method_name}` on #{mod} is declared as `abstract`. It does not have an implementation.")
      end
    # Note, this logic is duplicated (intentionally, for micro-perf) at `CallValidation.wrap_method_if_needed`,
    # make sure to keep changes in sync.
    elsif method_sig.check_level == :always || (method_sig.check_level == :tests && T::Private::RuntimeLevels.check_tests?)
      CallValidation.validate_call(self, original_method, method_sig, args, blk)
    else
      original_method.bind(self).call(*args, &blk)
    end
  end
  new_method = mod.instance_method(method_name)
  key = method_to_key(new_method)
  @sig_wrappers[key] = sig_block
  if current_declaration.final
    add_final_method(key)
    # use hook_mod, not mod, because for example, we want class C to be marked as having final if we def C.foo as
    # final. change this to mod to see some final_method tests fail.
    add_module_with_final(hook_mod)
  end
end

def self.add_final_method(method_key)
method_key)

def self.add_module_with_final(mod)
  @modules_with_final.add(mod)
  @modules_with_final.add(mod.singleton_class)
end

def self.build_sig(hook_mod, method_name, original_method, current_declaration, loc)
  begin
    # We allow `sig` in the current module's context (normal case) and
    if hook_mod != current_declaration.mod &&
        # inside `class << self`, and
        hook_mod.singleton_class != current_declaration.mod &&
        # on `self` at the top level of a file
        current_declaration.mod != TOP_SELF
      raise "A method (#{method_name}) is being added on a different class/module (#{hook_mod}) than the " \
            "last call to `sig` (#{current_declaration.mod}). Make sure each call " \
            "to `sig` is immediately followed by a method definition on the same " \
            "class/module."
    end
    signature = Signature.new(
      method: original_method,
      method_name: method_name,
      raw_arg_types: current_declaration.params,
      raw_return_type: current_declaration.returns,
      bind: current_declaration.bind,
      mode: current_declaration.mode,
      check_level: current_declaration.checked,
      on_failure: current_declaration.on_failure,
      override_allow_incompatible: current_declaration.override_allow_incompatible,
    )
    SignatureValidation.validate(signature)
    signature
  rescue => e
    super_method = original_method&.super_method
    super_signature = signature_for_method(super_method) if super_method
    T::Configuration.sig_validation_error_handler(
      e,
      method: original_method,
      declaration: current_declaration,
      signature: signature,
      super_signature: super_signature
    )
    Signature.new_untyped(method: original_method)
  end
end

def self.declare_sig(mod, arg, &blk)
  install_hooks(mod)
  if T::Private::DeclState.current.active_declaration
    T::Private::DeclState.current.reset!
    raise "You called sig twice without declaring a method inbetween"
  end
  if !arg.nil? && arg != :final
    raise "Invalid argument to `sig`: #{arg}"
  end
  loc = caller_locations(2, 1).first
  T::Private::DeclState.current.active_declaration = DeclarationBlock.new(mod, loc, blk, arg == :final)
  nil
end

def self.final_method?(method_key)
ude?(method_key)

def self.finalize_proc(decl)
  decl.finalized = true
  if decl.mode != Modes.standard
    raise "Procs cannot have override/abstract modifiers"
  end
  if decl.mod != PROC_TYPE
    raise "You are passing a DeclBuilder as a type. Did you accidentally use `self` inside a `sig` block?"
  end
  if decl.returns == ARG_NOT_PROVIDED
    raise "Procs must specify a return type"
  end
  if decl.on_failure != ARG_NOT_PROVIDED
    raise "Procs cannot use .on_failure"
  end
  if decl.params == ARG_NOT_PROVIDED
    decl.params = {}
  end
  T::Types::Proc.new(decl.params, decl.returns)
end

def self.has_sig_block_for_key(key)
key)

def self.has_sig_block_for_method(method)
  has_sig_block_for_key(method_to_key(method))
end

def self.install_hooks(mod)
  return if @installed_hooks.include?(mod)
  @installed_hooks << mod
  if mod == TOP_SELF
    # self at the top-level of a file is weirdly special in Ruby
    # The Ruby VM on startup creates an `Object.new` and stashes it.
    # Unlike when we're using sig inside a module, `self` is actually a
    # normal object, not an instance of Module.
    #
    # Thus we can't ask things like mod.singleton_class? (since that's
    # defined only on Module, not on Object) and even if we could, the places
    # where we need to install the hooks are special.
    mod.extend(SingletonMethodHooks) # def self.foo; end (at top level)
    Object.extend(MethodHooks)       # def foo; end      (at top level)
    return
  end
  if mod.singleton_class?
    mod.include(SingletonMethodHooks)
  else
    mod.extend(MethodHooks)
  end
  mod.extend(SingletonMethodHooks)
end

def self.key_to_method(key)
t("#")
id2ref(id.to_i)
(name)

def self.maybe_run_sig_block_for_key(key)
ey(key) if has_sig_block_for_key(key)

def self.maybe_run_sig_block_for_method(method)
  maybe_run_sig_block_for_key(method_to_key(method))
end

def self.method_owner_and_name_to_key(owner, name)
##{name}"

def self.method_to_key(method)
me_to_key(method.owner, method.name)

def self.module_with_final?(mod)
.include?(mod)

def self.register_forwarder(from_method, to_method, mode: Modes.overridable, remove_first_param: false)
  # Normalize the method (see comment in signature_for_key).
  from_method = from_method.owner.instance_method(from_method.name)
  from_key = method_to_key(from_method)
  maybe_run_sig_block_for_key(from_key)
  if @signatures_by_method.key?(from_key)
    raise "#{from_method} already has a method signature"
  end
  from_params = from_method.parameters
  if from_params.length != 2 || from_params[0][0] != :rest || from_params[1][0] != :block
    raise "forwarder methods should take a single splat param and a block param. `#{from_method}` " \
          "takes these params: #{from_params}. For help, ask #dev-productivity."
  end
  # If there's already a signature for to_method, we get `parameters` from there, to enable
  # chained forwarding. NB: we don't use `signature_for_key` here, because the normalization it
  # does is broken when `to_method` has been clobbered by another method.
  to_key = method_to_key(to_method)
  maybe_run_sig_block_for_key(to_key)
  to_params = @signatures_by_method[to_key]&.parameters || to_method.parameters
  if remove_first_param
    to_params = to_params[1..-1]
  end
  # We don't bother trying to preserve any types from to_signature because this won't be
  # statically analyzed, and the types will just get checked when the forwarding happens.
  from_signature = Signature.new_untyped(method: from_method, mode: mode, parameters: to_params)
  @signatures_by_method[from_key] = from_signature
end

def self.run_all_sig_blocks
  loop do
    break if @sig_wrappers.empty?
    key, _ = @sig_wrappers.first
    run_sig_block_for_key(key)
  end
end

def self.run_builder(declaration_block)
  builder = DeclBuilder.new(declaration_block.mod)
  builder
    .instance_exec(&declaration_block.blk)
    .finalize!
    .decl
end

def self.run_sig(hook_mod, method_name, original_method, declaration_block)
  current_declaration =
    begin
      run_builder(declaration_block)
    rescue DeclBuilder::BuilderError => e
      T::Configuration.sig_builder_error_handler(e, declaration_block.loc)
      nil
    end
  signature =
    if current_declaration
      build_sig(hook_mod, method_name, original_method, current_declaration, declaration_block.loc)
    else
      Signature.new_untyped(method: original_method)
    end
  unwrap_method(signature.method.owner, signature, original_method)
  signature
end

def self.run_sig_block_for_key(key)
[key]
_by_method[key]
n the sig block, perhaps in another thread.
 wrapper for #{key_to_method(key)}"
[key] = true
d[key]
 invocation of #{key_to_method(key)} raised, and the current one succeeded. Please don't do that."
e(key)

def self.run_sig_block_for_method(method)
  run_sig_block_for_key(method_to_key(method))
end

def self.set_final_checks_on_hooks(enable)
  is_enabled = @old_hooks != nil
  if enable == is_enabled
    return
  end
  if is_enabled
    @old_hooks.each(&:restore)
    @old_hooks = nil
  else
    old_included = T::Private::ClassUtils.replace_method(Module, :included) do |arg|
      old_included.bind(self).call(arg)
      ::T::Private::Methods._hook_impl(arg, arg.ancestors, self)
    end
    old_extended = T::Private::ClassUtils.replace_method(Module, :extended) do |arg|
      old_extended.bind(self).call(arg)
      ::T::Private::Methods._hook_impl(arg, arg.singleton_class.ancestors, self)
    end
    old_inherited = T::Private::ClassUtils.replace_method(Class, :inherited) do |arg|
      old_inherited.bind(self).call(arg)
      ::T::Private::Methods._hook_impl(arg, arg.ancestors, self)
    end
    @old_hooks = [old_included, old_extended, old_inherited]
  end
end

def self.signature_for_key(key)
_for_key(key)
 inherits a method `foo` from Base, then
od(:foo) != Base.instance_method(:foo) even though they resolve to the
larly, Foo.method(:bar) != Foo.singleton_class.instance_method(:bar).
the look up by the method on the owner (Base in this example).
od[key]

def self.signature_for_method(method)
  signature_for_key(method_to_key(method))
end

def self.start_proc
  DeclBuilder.new(PROC_TYPE)
end

def self.unwrap_method(mod, signature, original_method)
  maybe_wrapped_method = CallValidation.wrap_method_if_needed(mod, signature, original_method)
  @signatures_by_method[method_to_key(maybe_wrapped_method)] = signature
end