fix(jj): refresh LOCAL buffers in place on NOOP refresh

[dlyongemallo]

Motivated by #315 (comment).

Drop the JjAdapter:force_entry_refresh_on_noop, but explicitly call adapter:on_local_buffer_reused(f.bufnr) on every LOCAL side of the kept entry, to prevent flickering on tab switching in jj noted in #312 (comment).

[Copilot]

🟢 Approval recommended

The change is small, guarded, a no-op for non-jj adapters, and backed by targeted tests, with no dangling references or objective issues found.

Pull request overview

This PR changes how the jj adapter refreshes LOCAL (working-copy) buffers during a NOOP refresh. Previously, JjAdapter:force_entry_refresh_on_noop returned true for any LOCAL-touching range, forcing a full entry rebuild that tore down and re-loaded diff buffers (briefly attaching them to diffview://null) and reset the user's cycled layout. This override is removed; instead, the diff view's NOOP-keep path now explicitly routes each LOCAL side through adapter:on_local_buffer_reused, which reloads any jj-rewritten working-copy content in place via checktime. This addresses flicker on tab switching (#312) while keeping the kept-entry path intact for other adapters (a no-op for git/hg).

Changes:

• Remove JjAdapter:force_entry_refresh_on_noop, letting jj inherit the base false, and update the on_local_buffer_reused doc comment.
• In the diff view NOOP-keep branch, call adapter:on_local_buffer_reused for each valid LOCAL-side buffer.
• Update jj adapter tests and add a diff_view_spec test asserting on_local_buffer_reused is called for kept LOCAL entries.

File summaries

File	Description
lua/diffview/vcs/adapters/jj/init.lua	Drops the force_entry_refresh_on_noop override and refreshes the on_local_buffer_reused explanatory comment.
lua/diffview/scene/views/diff/diff_view.lua	Adds a guarded loop in the NOOP-keep branch that invokes on_local_buffer_reused on valid LOCAL buffers.
lua/diffview/tests/functional/jj_adapter_spec.lua	Updates the test to assert jj now inherits the base false for all rev pairs.
lua/diffview/tests/functional/diff_view_spec.lua	Adds a regression test verifying on_local_buffer_reused fires for LOCAL files kept across a NOOP refresh.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Balanced

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[jakubbortlik]

Hi David, thank you for the fix! It makes the responsiveness much better - the diffview://null flicker is gone. The redraw of the files when switching tabs is still slower with the jj adapter than with the git adapter, but I don't thank that's something that needs any more attention.