Investigate if signal names may be reused in DBC files

[erikbosch]

A CAN database consist of a number of messages, each containing a number of signals. At the moment the DBC Feeder design is based on the assumption that signal names are unique. We should better investigate if that is true, or be prepared that it maybe is not always true. According to https://support.vector.com/kb?id=kb_article_view&sysparm_article=KB0011320&sys_kb_id=4ae40ea41b2614148e9a535c2e4bcba7&spa=1 it seems names may be reused in different frames.

A few possible solutions:

Alt 1: Treat it as a limitation

State that behavior if there are multiple signals with the same name is undefined. We could refactor get_canid_for_signal so that it the first time it search for a signal name does not stop when finding first match, but rather continue and give a warning or error if it finds a second instance. So if you do not get a warning or error you are fine.

Alt 2: Mandatory message name

Make message name mandatory in the mapping, make sure it matches.

Alt 3: Optional message name

Only require message name if there are conflicts. I.e. if there are 2+ signals with same name give an error if no message name has been specified. if a message name has been specified verify that it match

[erikbosch]

This issue has been migrated from eclipse-kuksa/kuksa.val.feeders#122. Please see that issue for older comments.

[erikbosch]

Closed by #9