Hmm, I don't see why topic titles are limited to 260 bytes/characters? There doesn't seem to be a reason for this on the backend AFAICT, because flow_workflow.workflow_name doesn't appear to contain topic titles (or anything ever, for that matter) and the only place I can see the topic title going is flow_revision.rev_content which is a mediumblob. Is there a requirement that topic titles be valid page titles, maybe?

No, topic titles are not page titles (the page titles are UUID's, e.g. Topic:Sg9x5a5xhkit3g00).

@EBernhardson, @matthiasmullie, @DannyH, do you know the reason for this?

flow_workflow.workflow_name needs to be dropped, its is a vestige of a canceled idea. As for the topic titles its always been intended that they become the page names in the Topic namespace, we just havn't been able to fit that work into a sprint since production enabled $wgContentHandlerUseDB making it possible. I don't think that precludes topic titles being longer, they would just get truncated.

Based on the bug (T59453) that prompted the limit, it looks like 260 was arbitrarily chosen as something beyond which the interface starts to look very funny and wrong.

In T97499#1246541, @EBernhardson wrote:

flow_workflow.workflow_name needs to be dropped, its is a vestige of a canceled idea. As for the topic titles its always been intended that they become the page names in the Topic namespace, we just havn't been able to fit that work into a sprint since production enabled $wgContentHandlerUseDB making it possible. I don't think that precludes topic titles being longer, they would just get truncated.

Based on the bug (T59453) that prompted the limit, it looks like 260 was arbitrarily chosen as something beyond which the interface starts to look very funny and wrong.

OK, that makes sense. Note however that IIRC the title length limit is 255, so 260 is already too high if that's where we're headed.

In T97499#1246541, @EBernhardson wrote:

flow_workflow.workflow_name needs to be dropped, its is a vestige of a canceled idea.

Filed as T97607: Drop workflow_name.