From: davidm@...
Date: 2014-07-18T23:01:51+00:00
Subject: [ruby-core:63841] [ruby-trunk - Feature #10065] Make `gem env` command output valid YAML

Issue #10065 has been updated by David MacMahon.


It doesn't *need* to be YAML, but does it need *not* to be YAML?  It is sooooo close already why not make it YAML?  Besides, much of the info in the `GEM CONFIGURATION` section (where the only non-YAML syntax exists) comes from YAML files already (i.e. `${HOME}/.gemrc` and the system-wide `gemrc` file), so why output that in a different format?

How would the proposed change make it too clumsy to be useful?  If anything, it makes it less clumsy to use.  The current output of `gem environment` cannot be eval'd by Ruby, so what benefit does the rocket ship provide over the colon?

Without the proposed patch:

```bash
$ ruby -r pp -r yaml -e 'pp YAML.load `gem env`'
/Users/davidm/local/lib/ruby/2.1.0/psych.rb:370:in `parse': (<unknown>): did not find expected '-' indicator while parsing a block collection at line 16 column 6 (Psych::SyntaxError)
        from /Users/davidm/local/lib/ruby/2.1.0/psych.rb:370:in `parse_stream'
        from /Users/davidm/local/lib/ruby/2.1.0/psych.rb:318:in `parse'
        from /Users/davidm/local/lib/ruby/2.1.0/psych.rb:245:in `load'
        from -e:1:in `<main>'
```

Emulating the proposed patch at runtime:

```bash
$ ruby -r pp -r yaml -e 'pp YAML.load `gem env`.gsub(" =>",":")'
{"RubyGems Environment"=>
  [{"RUBYGEMS VERSION"=>"2.4.1"},
  # etc...
```


----------------------------------------
Feature #10065: Make `gem env` command output valid YAML
https://bugs.ruby-lang.org/issues/10065#change-47874

* Author: David MacMahon
* Status: Feedback
* Priority: Normal
* Assignee: Eric Hodel
* Category: lib/rubygems
* Target version: 
----------------------------------------
The output of `gem environment` is close to being valid YAML, but the `GEM CONFIGURATION` section uses `key => value` instead of `key: value` so the output cannot be parsed by YAML.  The attached patch changes just one line to make the output of `gem environment` be valid YAML.

I could not find a specification for the output of the `gem environment` command so I am filing this as a feature request rather than as a bug.

The attached patch is the minimum change necessary to create valid YAML.  I think the structure of the resulting YAML output is not optimal.  It is currently a one element Hash whose only value is an Array of one element Hashes.  Is it preferable to address that in a separate feature request or as an expansion of this one?


---Files--------------------------------
0001-Make-gem-env-command-output-valid-YAML.patch (1.12 KB)


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