Float 3.0 is misparsed as integer 3 in workflow YAML

[eregon]

Describe the bug

3.0 in a workflow is misparsed as integer 3.
Or at the very least, when it's parsed and then later converted to a string (with ${{ matrix.ruby }}), it's 3 and not the expected 3.0.

To Reproduce

jobs:
  test:
    strategy:
      matrix:
        os: [ ubuntu-latest ]
        ruby: [ 2.7, 3.0 ]
    name: ${{ matrix.os }} ${{ matrix.ruby }}
    runs-on: ${{ matrix.os }}
    steps:
    - uses: ruby/setup-ruby@v1
      with:
        ruby-version: ${{ matrix.ruby }}

Expected behavior
The input log and the job name should indicate 3.0, but we see 3 instead:
https://github.com/eregon/setup-ruby/runs/1503368422?check_suite_focus=true#step:3:3

Run ./
  with:
    ruby-version: 3
    bundler-cache: true
    bundler: default
    working-directory: .

This is important because ruby-version: 3.0 should pick version 3.0 but not version 3.1.
Due to this bug it would pick version 3.1.

I think in the YAML specification it's clear that floats and integers are different, so they should be kept that way too in workflow YAMLS, including when passing through ${{ matrix.ruby }}.

Using quotes [ 2.7, '3.0' ] is a workaround, but it should be unnecessary and it's much more verbose with many versions.

Runner Version and Platform

Version of your runner? 2.274.2
OS of the machine running the runner? Applies to all

[maxim-lobanov]

@eregon I have faced with the same issue in my own action https://github.com/maxim-lobanov/setup-xcode and decided that the best solution is updating my action's readme to recommend customers to use quotes in inputs.

I agree that the behavior that you have described looks a bit strange and it could be a bug. But I have found another problem if inputs are not quoted:

with:
    python-version: 3.10

This input will be parsed as 3.1 and it is definitely not that you expect to see. But based on YAML specification it is expected behavior because 3.10 is float value and trailing 0 can be removed.

A few words from https://symfony.com/doc/current/components/yaml/yaml_format.html

Strings in YAML can be wrapped both in single and double quotes. In some cases, they can also be unquoted
...
Finally, there are other cases when the strings must be quoted, no matter if you’re using single or double quotes:
...

• When the string looks like a number, such as integers (e.g. 2, 14, etc.), floats (e.g. 2.6, 14.9) and exponential numbers (e.g. 12e7, etc.) (otherwise, it would be treated as a numeric value);

So looks like that quoting is the best approach to save input as it is since strings can't be transformed somehow.
Also, All first-party actions recommend to wrap version input to quotes: https://github.com/actions/setup-node#usage

(Please do not take my answer as official position of actions/runner owners 😃 . I don't have context how YAML parsing works under hood in GitHub Actions and just say from position of third-party action's owner who faced with the same issue)

[eregon]

I agree for 3.10 it's a problem and there is no other way to fix that than to use quotes ('3.10').
I am taking advantage here that CRuby versions never had and most likely never will have a minor > 9 (i.e., it was 1.9 then 2.0).

When I started the action I considered both options, and I chose the unquoted variant because it worked as far as I could see just as good, and it's a lot more concise.
Compare:

jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu, macos]
        ruby: [2.5, 2.6, 2.7, head, debug, jruby, jruby-head, truffleruby, truffleruby-head]

and

jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu, macos]
        ruby: ['2.5', '2.6', '2.7', 'head', 'debug', 'jruby', 'jruby-head', 'truffleruby', 'truffleruby-head']

I find the second one much harder to read.
A practical consequence is the quoted variant actually doesn't fit on one line in the README.

An example in another project: https://github.com/jeremyevans/sequel/pull/1742/files

Also, as we can still see today, the unquoted versions were also used in TravisCI, which a lot of Ruby users come from:
https://docs.travis-ci.com/user/languages/ruby/

language: ruby
rvm:
  - 2.5
  - 2.6
  - jruby
  - truffleruby