Expected <document start> but found <scalar> syntax error wrt comment line between scalars

[jude]

I have a test.yml that is

a
#
b

that is returning an 'error syntax error: expected '', but found '' (syntax)' error.:

$ yamllint test.yml 
test.yml
  3:1       error    syntax error: expected '<document start>', but found '<scalar>' (syntax)

It looks like the error is only happenign when a comment line is in the middle of the file:

• If I remove the line with the '#', than yamllint doesn't return an error.
• If I change the '#' character to an 'x', then yamllint doesn't return an error.
• If I replace the '#' character with a blank line, then yamllint doesn't return an error.
• if I remove either the 'a' or 'b' lines so the comment is the first or last line of the file, yamllint doesn't return an error.
• If I change the comment line to '# test', then I still get the " expected '', but found '' (syntax)' error."

My .yamllint file is

extends: default
rules:
  document-start: disable

I'm using yamllint 1.33.0 from https://dl.fedoraproject.org/pub/epel/8/Everything/x86_64/Packages/y/yamllint-1.33.0-1.el8.noarch.rpm

My workaround was to change the file as per below, converting the scalars to empty maps.

a:
#
b:

[adrienverge]

Hello,

I don't think your example is valid YAML, which explains the error that yamllint outputs.

You can try different YAML parsers on https://play.yaml.io/main/parser. I tried the Python parser (PyYAML) and the JavaScript one (yaml) and both report a syntax error.