fix(view): serialise _set_file so rapid navigation lands on the latest file

[dlyongemallo]

No description provided.

[Copilot]

Pull request overview

This PR fixes a rapid-navigation race in Diffview’s file switching by serializing StandardView:_set_file() so overlapping file-open operations are coalesced and only the latest requested file is ultimately opened.

Changes:

• Implemented a queued/serialized _set_file workflow in StandardView using _set_file_in_flight + _set_file_pending.
• Removed per-subclass _set_file implementations in DiffView and FileHistoryView, and introduced a _detach_files_for_next() hook for subclass-specific detach behavior.
• Added functional tests covering the queuing/serialization contract and verifying subclass detach behavior.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
lua/diffview/scene/views/standard/standard_view.lua	Adds _set_file serialization and a drain worker to coalesce concurrent file-switch requests.
lua/diffview/scene/views/diff/diff_view.lua	Removes subclass _set_file so DiffView inherits the serialized StandardView behavior.
lua/diffview/scene/views/file_history/file_history_view.lua	Replaces custom _set_file with _detach_files_for_next() override (swap semantics).
lua/diffview/tests/functional/standard_view_spec.lua	Adds functional tests for _set_file serialization and detach-hook behavior.
lua/diffview/tests/functional/diff_view_spec.lua	Notes that _set_file coalescing is tested via StandardView.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

lua/diffview/tests/functional/standard_view_spec.lua:403

• Similar to the serialization test above: this helper relies on calling cbs[1]() to let the _set_file worker complete and release its Future from async._handles. If anything in the pcall body errors before the callback is invoked, the suspended coroutine will linger for the rest of the suite. Consider ensuring callbacks are drained in a protected cleanup section that runs even when the test fails (e.g., xpcall + cleanup, or always pcall any collected callbacks before rethrowing).

    local ok, err = pcall(function()
      StandardView._set_file(view, target)
      -- Let the worker open the requested file so we can inspect the
      -- captured layout method calls, then resolve to drain the loop.
      cbs[1]()
    end)

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.