a slightly better version of restore_yaml_comments

[hebote]

I discovered that config.dump() throws StopIteration if my config_default.yaml has comments in the end of the file.

The reason was how original restore_yaml_comments() processed default_data.
Also, original restore_yaml_comments() would put a comment in front of ALL the keys with the same name.
And if a comment was indented, the original restore_yaml_comments() ignored it.

I made some changes that fix these three problems.

It is not ideal - for example, it does not align indentation and I imagine a case where it would misplace a comment, but it improves current implementation.

[sampsyo]

Interesting! Thanks for looking into this. Would you mind adding some tests to specify the behavior you're going for here?

[hebote]

I will add a test. Would it be fine if it will call only restore_yaml_comments() or you would like to call dump()?

[sampsyo]

Cool! I guess it would be nice to keep the name, just in case anyone is depending on that function directly.

[hebote]

Here it is.

[hebote]

I have been playing with the code and found out that in case of merging configuration from several sources my code fails to perform correctly. Do not incorporate it to master, I am looking into this.

[hebote]

This version processes "reordered" texts (e.g. a section was at the top of config_default.yaml file and dump() provides it in the bottom of it's output).

Benefits:

• No StopIteration exceptions.
• Indented comments supported.

Limitations:

• In case of several keys with the same name the comment will appear with the first occurrence only.
• Indentation is not aligned.

IMO to overcome the limitations the only way is to parse text back to YAML object.

[hebote]

"Indentation is not aligned." this one is regarding indentation of comments.
E.g. a one-space indentation is fully valid for YAML and dump() uses 4 space indentation.