{"record":{"id":"af17d8d63f3e77e6","repo":"Textualize/textual","slug":"pane-id-must-be-a-non-empty-string-or-a-tabpane","errorCode":null,"errorMessage":"'pane_id' must be a non-empty string or a TabPane with an id.","messagePattern":"'pane_id' must be a non-empty string or a TabPane with an id\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"src/textual/widgets/_tabbed_content.py","lineNumber":593,"sourceCode":"    def tab_count(self) -> int:\n        \"\"\"Total number of tabs.\"\"\"\n        return self.get_child_by_type(ContentTabs).tab_count\n\n    def get_tab(self, pane_id: str | TabPane) -> Tab:\n        \"\"\"Get the `Tab` associated with the given ID or `TabPane`.\n\n        Args:\n            pane_id: The ID of the pane, or the pane itself.\n\n        Returns:\n            The Tab associated with the ID.\n\n        Raises:\n            ValueError: Raised if no ID was available.\n        \"\"\"\n        if target_id := (pane_id if isinstance(pane_id, str) else pane_id.id):\n            return self.get_child_by_type(ContentTabs).get_content_tab(target_id)\n        raise ValueError(\n            \"'pane_id' must be a non-empty string or a TabPane with an id.\"\n        )\n\n    def get_pane(self, pane_id: str | ContentTab) -> TabPane:\n        \"\"\"Get the `TabPane` associated with the given ID or tab.\n\n        Args:\n            pane_id: The ID of the pane to get, or the Tab it is associated with.\n\n        Returns:\n            The `TabPane` associated with the ID or the given tab.\n\n        Raises:\n            ValueError: Raised if no ID was available.\n        \"\"\"\n        target_id: str | None = None\n        if isinstance(pane_id, ContentTab):\n            target_id = (","sourceCodeStart":575,"sourceCodeEnd":611,"githubUrl":"https://github.com/Textualize/textual/blob/06dbeef4bb70fb718236aa418ed658ef4667a126/src/textual/widgets/_tabbed_content.py#L575-L611","documentation":"Raised by TabbedContent.get_tab when pane_id is neither a non-empty string nor an object (TabPane) with a truthy .id. The method needs an id to look up the tab in the ContentTabs child, so an empty string or an id-less TabPane fails.","triggerScenarios":"get_tab(tabbed_content.active_pane) where the TabPane has no id set; get_tab('') ; passing a TabPane constructed without id=.","commonSituations":"Querying the tab for the active pane when panes were created without ids, or programmatic tab lookup with user-supplied ids that may be empty.","solutions":["Give every TabPane an explicit id: TabPane('Title', id='pane-one').","Guard: check pane.id is truthy before calling get_tab.","Pass the known string id instead of the pane object."],"exampleFix":"# before\nTabPane('Settings')  # no id\n# ...\ntabbed_content.get_tab(tabbed_content.active_pane)  # raises\n# after\nTabPane('Settings', id='settings')\n# ...\ntabbed_content.get_tab('settings')","handlingStrategy":"validation","validationCode":"pane_id = pane_id if isinstance(pane_id, str) else pane_id.id\nif pane_id:\n    tab = tabbed_content.get_tab(pane_id)","typeGuard":null,"tryCatchPattern":"try:\n    tab = tabbed_content.get_tab(pane_id)\nexcept ValueError:\n    tab = None","preventionTips":["Always set id= on every TabPane","Validate non-empty ids from user input"],"tags":["tabbed-content","missing-id","textual"],"backgroundTag":"missing-required-id","analyzedSha":"06dbeef4bb70fb718236aa418ed658ef4667a126","analyzedAt":"2026-08-27T02:36:57.214Z","schemaVersion":2},"datasetVersion":"2026-08-27T03:17:27.898Z"}