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# frozen_string_literal: true
require 'appmap/handler/function'
module AppMap
module Handler
# Handler class for Kernel#eval.
#
# Second argument to eval is a Binding, which despite the name (and
# the accessible methods) in addition to locals and receiver also
# encapsulates the entire execution context, in particular including
# the lexical scope. This is especially important for constant lookup
# and definition.
#
# If the binding is not provided, by default eval will run in the
# current frame. Since we call it here, this will mean the #do_call
# frame, which would make AppMap::Handler::Eval the lexical scope
# for constant lookup and definition; as a consequence
# eg. `eval "class Foo; end"` would define
# AppMap::Handler::Eval::Foo instead of defining it in
# the module where the original call was made.
#
# To avoid this, we explicitly substitute the correct execution
# context, up several stack frames.
class Eval < Function
# The depth of the frame we need to pluck out:
# 1. Hook::Method#do_call
# 2. Hook::Method#trace_call
# 3. Hook::Method#call
# 4. proc generated by Hook::Method#hook_method_def
# 5. the (intended) frame of the original eval that we hooked
# Note it needs to be adjusted if this call sequence changes.
FRAME_DEPTH = 5
def do_call(receiver, src = nil, context = nil, *rest)
context ||= AppMap.caller_binding FRAME_DEPTH
hook_method.bind(receiver).call(src, context, *rest)
end
end
end
end
Version data entries
15 entries across 15 versions & 1 rubygems