[ruby-core:90754] [Ruby trunk Feature#15287] New TracePoint events to support loading features

[eregontp@gmail.com]

Issue #15287 has been updated by Eregon (Benoit Daloze).


I wonder, what purpose do you envision for `instruction_sequence`?
It is of course MRI-specific (as documented), so I'm not sure how one would use it on other Ruby implementations.

> I named `eval_script` because we can not get source code other than *eval methods (not by `require` and `load`).

That would be a very useful feature though, and could maybe be created lazily when the method is called.
It seems somewhat similar to https://github.com/jruby/jruby/issues/5206#issue-328885424, which also wants to be able to modify the source on the fly.

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Feature #15287: New TracePoint events to support loading features
https://bugs.ruby-lang.org/issues/15287#change-75927

* Author: ko1 (Koichi Sasada)
* Status: Closed
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
* Target version: 2.6
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# Abstract

I propose the following new TracePoint events:

* `loaded` (invoked after `require`/`load`)
* `method_added` (invoked after method definition)

# Background

Sometimes we need to hook loading iseq. For example, checking loading files and so on.
Also we want to know what kind of methods are defined.

For both purpose, we can use some hook methods such as `Module#method_added` and so on.
However, defining methods we can override this features.
So that if we have two tools/libraries using this feature, they can be conflicted.

# Proposal

Introduce new TracePoint events:

* `loaded` (invoked after `require`/`load`)
* `method_added` (invoked after method definition)

Also the following methods can be added:

* Active only `loaded` event:
  * `TracePoint#loaded_feature` returns feature name.
  * `TracePoint#loaded_iseq` returns `RubyVM::InstructionSequence` object (MRI only, internal feature)

# Optional proposal

Add `class_added` alias name for `class` event.




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