[ruby-core:82895] [Ruby trunk Feature#13923] Idiom to release resources safely, with less indentations

Issue #13923 has been updated by Eregon (Benoit Daloze).


tagomoris (Satoshi TAGOMORI) wrote:
> With this code, storage will not be closed if `buffer.close` raises exceptions.

IMHO if buffer.close raises an exception then that should be fixed and not silently ignored.
(e.g. if close fails it could mean the contents is not properly flushed and might be very hard to debug).

A more common way to write code using resources in Ruby is to use blocks:

    File.open("foo") do |file|
      file.read
    end

----------------------------------------
Feature #13923: Idiom to release resources safely, with less indentations
https://bugs.ruby-lang.org/issues/13923#change-66794

* Author: tagomoris (Satoshi TAGOMORI)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
In programs which grabs and releases resources very often, we need to write so much begin-ensure clauses.

```ruby
begin
  storage = getStorage()
  begin
    buffer = storage.get(buffer_id)

    # ...
  ensure
    buffer.close if buffer
  end
rescue StorageError => e
  # ...
ensure
  storage.close if storage
end
```

Such code makes our code fat, and difficult to understand.
I want to write such code like below:

```ruby
# Class of storage and buffer should include a module (like Closeable)
# or be checked with respond_to?(:close)

begin(storage = getStorage(); buffer = storage.get(buffer_id)
  # ...
rescue StorageError => e
  # ...
end
# (buffer.close if buffer) rescue nil
# (storage.close if storage) rescue nil
```

Other languages also have similar features:

* Java: try-with-resources
* Python: with




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