From: mame@ruby-lang.org
To: ruby-core@ruby-lang.org
Subject: [ruby-core:103492] [Ruby master Bug#16983] RubyVM::AbstractSyntaxTree.of(method) returns meaningless node if the method is defined in eval
Date: Sat, 17 Apr 2021 07:21:17 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-91588.20210417072116.11727@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-16983.20200624125756.11727@ruby-lang.org
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/
next prev parent reply other threads:[~2021-04-17 7:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 12:57 [ruby-core:98931] [Ruby master Bug#16983] RubyVM::AbstractSyntaxTree.of(method) returns meaningless node if the method is defined in eval kuwabara
2020-08-28 21:35 ` [ruby-core:99759] " merch-redmine
2021-04-17 7:21 ` mame [this message]
2021-05-21 19:11 ` [ruby-core:103957] " merch-redmine
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