Feature #14694: TracePoint#parameters

• Status: Closed
• Priority: Normal
• Assignee: -
• Target version: -

[mame (Yusuke Endoh)]

Currently, we cannot get the block parameters' information in TracePoint b_call hooks.
Also, it is (possible but) not easy to get the method parameters in call hooks.

[1] https://speakerdeck.com/valich/automated-type-contracts-generation-1#29

To make it easy, how about adding TracePoint#parameters?

TracePoint.new(:call, :b_call, :c_call) do |tp|
  p [tp.event, tp.parameters]
end

# call
def foo(a, b=1); end; foo(1)
#=> [:call, [[:req, :a], [:opt, :b]]]

# b_call
1.times {|x, y=1| }
#=> [:b_call, [[:req, :x], [:opt, :y]]]

# c_call
"".getbyte(0)
#=> [:c_call, [[:req]]]

A patch is attached.

[mame (Yusuke Endoh)]

• Backport deleted (2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN)
• Tracker changed from Bug to Feature

[mame (Yusuke Endoh)]

• Status changed from Open to Closed

Applied in changeset trunk|r63562.

---

Add TracePoint#parameters

It can be used to get the parameters' information of method and block.
There was no way to get block parameters.
It was possible but ineffective to get method parameters via Method
object: tp.defined_class.method(tp.method_id).parameters
TracePoint#parameters allows us to get the information easily.
[Feature #14694]