From: mame@... Date: 2021-04-17T07:21:17+00:00 Subject: [ruby-core:103492] [Ruby master Bug#16983] RubyVM::AbstractSyntaxTree.of(method) returns meaningless node if the method is defined in eval Issue #16983 has been updated by mame (Yusuke Endoh). Assignee set to ko1 (Koichi Sasada) Status changed from Open to Assigned This ticket was discussed on dev-meeting. A method (or proc) created in an `eval` context should be marked and `AST.of` should raise an exception against a marked method. @ko1 said that he will do. ---------------------------------------- Bug #16983: RubyVM::AbstractSyntaxTree.of(method) returns meaningless node if the method is defined in eval https://bugs.ruby-lang.org/issues/16983#change-91588 * Author: pocke (Masataka Kuwabara) * Status: Assigned * Priority: Normal * Assignee: ko1 (Koichi Sasada) * ruby -v: ruby 2.8.0dev (2020-06-23T13:58:26Z master dc351ff984) [x86_64-linux] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- # Problem `RubyVM::AST.of(method)` returns a meaningless node if the method is defined in eval. For example: ```ruby p 'blah' eval <<~RUBY, binding, __FILE__, __LINE__ + 1 def foo end RUBY method = method(:foo) pp RubyVM::AbstractSyntaxTree.of(method) # => (STR@3:5-3:12 "def foo\n" + "end\n") ``` I expect the node of `foo` method, or `nil`. But it returns a `STR` node. It becomes a big problem when `AST.of` receives arbitrary methods. Because we can't distinguish a method is defined in `eval` or not. It means we can't believe the returned value of `AST.of` if the method may receive a method defined in `eval`. For example: ```ruby def do_something_for_each_method_ast(klass) klass.instance_methods(false).each do |m| ast = RubyVM::AbstractSyntaxTree.of(klass.instance_method(m)) next unless ast do_something ast end end class A eval <<~RUBY, binding, __FILE__, __LINE__ + 1 def foo end RUBY end do_something_for_each_method_ast A ``` In the example, I expect the `do_something` method receives only node for a method definition, but it may pass a wrong node if any method is defined in `eval`. # Cause (I guess) I guess the cause is misleading node number. In and out of an `eval` block uses different sequences of node number. So if I specify `__FILE__` to `eval`, the actual file and code in `eval` may have the same node number. For example ```ruby p 'blah' # Node number for 'blah' is 1, file name is "test.rb" eval <<~RUBY, binding, __FILE__, __LINE__ + 1 def foo # Node number for `def` is also 1, file name is also "test.rb" end RUBY method = method(:foo) # It finds a node from node number 1 by reading "test.rb", so it get the str node. pp RubyVM::AbstractSyntaxTree.of(method) # => (STR@3:5-3:12 "def foo\n" + "end\n") ``` -- https://bugs.ruby-lang.org/ Unsubscribe: