[#106341] [Ruby master Bug#18369] users.detect(:name, "Dorian") as shorthand for users.detect { |user| user.name == "Dorian" } — dorianmariefr <noreply@...>
Issue #18369 has been reported by dorianmariefr (Dorian Mari辿).
14 messages
2021/11/30
[#106351] [Ruby master Bug#18371] Release branches (release information in general) — "tenderlovemaking (Aaron Patterson)" <noreply@...>
Issue #18371 has been reported by tenderlovemaking (Aaron Patterson).
7 messages
2021/11/30
[ruby-core:105990] [Ruby master Feature#16663] Add block or filtered forms of Kernel#caller to allow early bail-out
From:
"Eregon (Benoit Daloze)" <noreply@...>
Date:
2021-11-09 16:32:07 UTC
List:
ruby-core #105990
Issue #16663 has been updated by Eregon (Benoit Daloze).
@zverok No, that can't work because then in your example the actual place where the stack is queried is e.g. inside `#find` which e.g. adds an extra entry on the stack.
Also in general we can't use Enumerable/Enumerator here, the passed caller information is only meaningful at the place `caller` was called.
We can have arbitrary calls from the block of `caller`, that's fine, but we can't ever return "something" that exposes the stack where `caller` was called, because that something would then need to eagerly capture the stack and miss the whole point of this feature.
Or that "something" would iterate the stack at the place it's actually used (not where `lazy_caller` was called), and that would just be confusing.
----------------------------------------
Feature #16663: Add block or filtered forms of Kernel#caller to allow early bail-out
https://bugs.ruby-lang.org/issues/16663#change-94536
* Author: headius (Charles Nutter)
* Status: Open
* Priority: Normal
----------------------------------------
There are many libraries that use `caller` or `caller_locations` to gather stack information for logging or instrumentation. These methods generate an array of informational stack frames based on the current call stack.
Both methods accept parameters for `level` (skip some number of Ruby frames) and `length` (only return this many frames). However many use cases are unable to provide one or both of these.
Instrumentation uses, for example, may need to skip an unknown number of frames at the top of the trace, such as to dig out of rspec plumbing or active_record internals and report the first line of user code. In such cases, the typical pattern is to simply request *all* frames and then filter out the one that is desired.
This leads to a great deal of wasted work gathering those frames and constructing objects to carry them to the user. On optimizing runtimes like JRuby and TruffleRuby, it can have a tremendous impact on performance, since each frame has a much higher cost than on CRuby.
I propose that we need a new form of `caller` that takes a block for processing each element.
```ruby
def find_matching_frame(regex)
caller do |frame|
return frame if frame.file =~ regex
end
end
```
An alternative API would be to allow passing a query object as a keyword argument, avoiding the block dispatch by performing the match internally:
```ruby
def find_matching_frame(regex)
caller(file: regex)
end
```
This API would provide a middle ground between explicitly specifying a maximum number of stack frames and asking for all frames. Most common, hot-path uses of `caller` could be replaced by these forms, reducing overhead on all Ruby implementations and drastically reducing it where stack traces are expensive.
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