Narrow Git History panel stops responding after tapping Branches on an empty or failed view

[Defmon3]

Seen on: component/git-history

What it fixes

On a phone-width or narrow right panel, Git History shows Branches and Details buttons in its header. If the history list is empty, failed to load, or the folder is not a repository, tapping Branches opens nothing, and the whole header, including Refresh, stops responding to taps. The only way out is to switch to another tab and back.

How to fix it

The branches and details sheets should exist in every panel state, not only when commits are loaded, or the header buttons should be disabled in the states that cannot show them. Either way, a tap on Branches must never leave the header inert with no sheet to close. Ships with a test for the error state in narrow layout.

[Defmon3]

Technical appendix: Narrow Git History panel stops responding after tapping Branches on an empty or failed view

Investigated on branch component/git-history at commit 821fc7f.

Findings

• File apps/web/src/components/GitHistoryPanel.tsx, component GitHistoryPanel: the <header> element carries inert whenever the mobilePane state is non-null. The header renders in every panel state.
• The Branches and Details header buttons render whenever the layout is not wide (isWideLayout false). Their click handlers set mobilePane to "refs" or "details" without checking whether the panel can show a sheet.
• The two Sheet elements that host the refs pane and the details pane are rendered only inside the last branch of the render chain, which is reached only when the initial load has finished, there is no error with an empty list, the folder is a repository, and at least one commit is loaded. The loading, error, not-a-repository, and empty-repository branches render no Sheet.
• mobilePane is reset to null by: the wide-layout effect, the effect that runs when props.active is false, the refresh and target-change handlers, and the sheets' own close callbacks. None of these fires from inside the inert header.
• The Retry button in the error state sits outside the header, so it stays tappable there. In the not-a-repository and empty-repository states nothing in the panel body is interactive.
• Established by reading the component. Not reproduced in a browser. apps/web/src/components/GitHistoryPanel.test.tsx contains no test that renders the narrow layout sheets or taps the Branches button in any state.

The problem

Observed: in narrow layout, with the history list empty, failed, or the folder not a repository, tapping Branches opens nothing and the header, including Refresh, stops responding until the tab is switched.

Once fixed: in every panel state, tapping Branches either opens the branches sheet or does nothing visible, and the header keeps responding.