URGENT: Fix broken gtkmm entry

[rhaschke]

#40772, merged yesterday, breaks rosdep with the following error:

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml]:
  while scanning a plain scalar
  in "<string>", line 3911, column 12:
      gentoo: [dev-cpp/gtkmm:3.0]
               ^
found unexpected ':'
  in "<string>", line 3911, column 25:
      gentoo: [dev-cpp/gtkmm:3.0]
                            ^

Obviously, names containing a colon should be quoted, such that they are not interpreted as a map.

[cottsay]

Obviously, names containing a colon should be quoted.

I'm actually not convinced that this is true. Keys maybe, but this is a value.

That rule works fine on my machine:

$ rosdep resolve libgtkmm3.0-dev --os gentoo:
#portage
dev-cpp/gtkmm:3.0

Also, yamllint and our CI both process the rule correctly. Under what circumstances are you seeing this error?

Separately, please use single quotes as is the convention in this file.

[cottsay]

The oldest configuration I have handy is Python 3.6 with PyYAML 3.13, and it works there:

Python 3.6.8 (default, Nov 14 2023, 16:29:52) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import yaml; yaml.__version__
'3.13'
>>> yaml.safe_load('foo: bar:baz')
{'foo': 'bar:baz'}

The latest version of Python 3 and PyYAML appears to work as well:

Python 3.12.2 (main, Feb 21 2024, 00:00:00) [GCC 13.2.1 20231205 (Red Hat 13.2.1-6)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import yaml; yaml.__version__
'6.0.1'
>>> yaml.safe_load('foo: bar:baz')
{'foo': 'bar:baz'}

[cottsay]

Oh, interesting, I got the older configuration to break when the value is placed in a list.

Python 3.6.8 (default, Nov 14 2023, 16:29:52) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import yaml; yaml.__version__
'3.13'
>>> yaml.safe_load('foo: [bar:baz]')
...
yaml.scanner.ScannerError: while scanning a plain scalar
  in "<unicode string>", line 1, column 7:
    foo: [bar:baz]
          ^
found unexpected ':'
  in "<unicode string>", line 1, column 10:
    foo: [bar:baz]
             ^
Please check http://pyyaml.org/wiki/YAMLColonInFlowContext for details.

So maybe somewhere between 3.13 and 5.3.1 PyYAML started supporting this syntax.

Seems reasonably low-cost to just support the older PyYAML versions, let's fix the quotes though.

[cottsay]

Closes: #41057

[cottsay]

Follow-up: #41060