Tabs.Cleared documentation a little ambiguous

[davep]

The Tabs.Cleared message is documented as being "Sent when there are no active tabs. This can occur when Tabs are cleared, or if all tabs are hidden". This suggests that Tabs.cleared or hiding every single Tab are the only routes to causing this message to be posted.

From what I can see simply setting Tabs.active to an empty string will cause this message to be posted too. The documentation should probably make it clear that this will also be a cause.

A followup question, which might need to spin off into another issue, is: does it make sense that Tabs.active can be set (outwith of the workings of Tabs) to an empty string? And if the answer is yes, the next question would be "why does doing this cause Tabs to behave as if the last-active-tab were still the active tab?"

[davep]

Related to this, TabbedContent.active can't be set to an empty string:

╭──────────────────────────────────────────────── Traceback (most recent call last) ─────────────────────────────────────────────────╮
│ /Users/davep/develop/python/textual/../textual-sandbox/tabbed_content_message_testing.py:37 in empty_active                        │
│                                                                                                                                    │
│   34 │                                                                                        ╭────────── locals ──────────╮       │
│   35 │   @on(Button.Pressed, "#empty-active")                                                 │ self = WrapperForTesting() │       │
│   36 │   def empty_active(self) -> None:                                                      ╰────────────────────────────╯       │
│ ❱ 37 │   │   self.query_one(TabbedContent).active = ""                                                                             │
│   38 │                                                                                                                             │
│   39 │   @on(Button.Pressed, "#hide-all")                                                                                          │
│   40 │   def hide_all(self) -> None:                                                                                               │
│                                                                                                                                    │
│ /Users/davep/develop/python/textual/src/textual/widgets/_tabbed_content.py:345 in validate_active                                  │
│                                                                                                                                    │
│   342 │   │   │   ValueError: If the active attribute is set to empty string when there are ta ╭───────── locals ─────────╮        │
│   343 │   │   """                                                                              │ active = ''              │        │
│   344 │   │   if not active and self.get_child_by_type(ContentSwitcher).current:               │   self = TabbedContent() │        │
│ ❱ 345 │   │   │   raise ValueError("'active' tab must not be empty string.")                   ╰──────────────────────────╯        │
│   346 │   │   return active                                                                                                        │
│   347 │                                                                                                                            │
│   348 │   @staticmethod                                                                                                            │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
ValueError: 'active' tab must not be empty string.

This does raise the question: should there be this difference between Tabs and TabbedContent?

[willmcgugan]

The probably should be the same.

[github-actions]

Don't forget to star the repository!

Follow @textualizeio for Textual updates.