Plain scalars with colons inside flow mappings & sequences are valid YAML

[jstoiko]

Scalars with colons, such as URLs, when they are inside flow mappings, e.g.

a: {b: https://github.com/go-yaml/yaml}

and sequences, e.g.

a: [https://github.com/go-yaml/yaml]

make go-yaml choke with found unexpected ':'.

The specs however explicitly allow it:

Normally, YAML insists the “:” mapping value indicator be separated from the value by white space. A benefit of this restriction is that the “:” character can be used inside plain scalars, as long as it is not followed by white space. This allows for unquoted URLs and timestamps.

On a related note, libyaml (the reference parser for YAML in C) had a similar issue but it seems to have been addressed and about to be released.

[rogpeppe]

Fixed in devel branch by PR #305

[asomov]

I see no tests added for the failing corner cases:

{a: 1}
{a:1}
{a:}