From: "byroot (Jean Boussier) via ruby-core" <ruby-core@...>
Date: 2024-03-14T15:08:21+00:00
Subject: [ruby-core:117180] [Ruby master Feature#20335] `Thread.each_caller_location` should accept the same arguments as `caller` and `caller_locations`

Issue #20335 has been updated by byroot (Jean Boussier).


> I think omitting the first N frames is useful.

Agreed, that's the only one I want. The reason I started the issue by asking for the same parameters is purely consistency.

Now, if there are valid reasons not to support some (like you exposed), I'm totally fine with deliberately not supporting them. But what I'm trying to say is we should start with the same feature set and then selectively remove the one that may be problematic.

So I suppose at that stage the proposal would be:

```ruby
Thread.each_caller_location(1) # skip first frame
Thread.each_caller_location(1, 20) # skip first frame, yield the next 20 frames
Thread.each_caller_location(1..20) # ArgumentError
```

Is that correct?

----------------------------------------
Feature #20335: `Thread.each_caller_location` should accept the same arguments as `caller` and `caller_locations`
https://bugs.ruby-lang.org/issues/20335#change-107270

* Author: byroot (Jean Boussier)
* Status: Open
----------------------------------------
`Thread.each_caller_location` was added to Ruby 3.2 as part of [Feature #16663] and is a very useful API for emitting warnings with a proper source location and similar use cases.

However in many of the cases where I used it, or seen it used, it was needed to skip the first, or a couple frames:

Examples:

Sorbet: https://github.com/Shopify/sorbet/blob/b27a14c247ace7cabdf0f348bfb11fdf0b7e9ab4/gems/sorbet-runtime/lib/types/private/caller_utils.rb#L6-L18

```ruby
    def self.find_caller
      skiped_first = false
      Thread.each_caller_location do |loc|
        unless skiped_first
          skiped_first = true
          next
        end

        next if loc.path&.start_with?("<internal:")

        return loc if yield(loc)
      end
      nil
    end
```

@fxn 's PR: https://github.com/ruby/ruby/blob/9c2e686719a5a4df5ea0b8a3b6a373ca6003c229/lib/bundled_gems.rb#L140-L146

```ruby
      frames_to_skip = 2
      location = nil
      Thread.each_caller_location do |cl|
        if frames_to_skip >= 1
          frames_to_skip -= 1
          next
        end
      # snipp...

```

### Proposal

I think it would be very useful if `Thread.each_caller_location` accepted the same arguments as `caller` and `caller_locations`:

```ruby
#each_caller_location(start = 1, length = nil)
#each_caller_location(range)
```

@jeremyevans0 what do you think?





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