Desktop 2.0.20 (macOS): file diff view throws on partial diffs — "loadDiffFiles is required" #52263

Activity

1. github-actions

   assigned

   Brendonovich

   on Sep 30, 2026
2. github-actions commented on Sep 30, 2026

   

   github-actionsBot

   on Sep 30, 2026 – with GitHub Actions

   Contributor

   More actions

   ---

   This issue might be a duplicate of an existing issue. Please check:

   • #52213: Reports the same Desktop 2.0.20 macOS crash when rendering partial diffs because the loadDiffFiles callback is missing.
3. opencodejr commented on Oct 28, 2026

   

   opencodejrBot

   on Oct 28, 2026

   More actions

   Thanks for the detailed report. I've confirmed this is a regression from 2.0.19, and it still happens on the latest dev (86ce19d).

   I couldn't run the desktop app here, so I reproduced it with the diff library the app uses (@pierre/diffs), set up the way the review pane sets it up:

   • A normal git diff of a modified file with more than one hunk is turned into a partial diff. This doesn't need a very large change.
   • When the review pane's "show all lines" (expand) mode is on, the app turns on expandUnchanged for the diff view. Since @pierre/diffs 1.5 (shipped in 2.0.20), rendering a partial diff with that option and without loadDiffFiles throws FileDiff: loadDiffFiles is required to load full files for a partial diff.
   • The app never passes loadDiffFiles, so it crashes. @pierre/diffs 1.2.10, the version 2.0.19 used, renders the same diff fine.

   The script below reproduces it: with expand off the diff renders, and with expand on it throws.

   Possible workaround until it's fixed: switch the review pane back to "hide non-diff lines" (collapse) mode. Partial diffs render normally there.

   Related: #52213 (your earlier report of the same problem), and #57441 / #58881 (blank diff pane reports, possibly the same root cause).

   Reproduction script (repro.ts)

   // Reproduces #52263 at the library level: the desktop review pane renders a partial
   // (hunk-only) "change" diff through @pierre/diffs FileDiff with `expandUnchanged`
   // set from the review "expand" mode, but never passes `loadDiffFiles`.
   import { GlobalRegistrator } from "@happy-dom/global-registrator"
   GlobalRegistrator.register()
   const { FileDiff, parsePatchFiles } = await import("@pierre/diffs")
   
   // A modified file with two separated hunks, as produced by `git diff` on a large change.
   const old = Array.from({ length: 60 }, (_, i) => `line ${i + 1}`)
   const patch = [
     "diff --git a/big.ts b/big.ts",
     "index 1111111..2222222 100644",
     "--- a/big.ts",
     "+++ b/big.ts",
     "@@ -4,3 +4,3 @@",
     " line 4",
     "-line 5",
     "+line 5 changed",
     " line 6",
     "@@ -50,3 +50,3 @@",
     " line 50",
     "-line 51",
     "+line 51 changed",
     " line 52",
     "",
   ].join("\n")
   const fileDiff = parsePatchFiles(patch)[0]!.files[0]!
   console.log("type:", fileDiff.type, "isPartial:", fileDiff.isPartial)
   
   for (const expandUnchanged of [false, true]) {
     const container = document.createElement("div")
     document.body.appendChild(container)
     const view = new FileDiff({ expandUnchanged, hunkSeparators: "simple" })
     try {
       view.render({ fileDiff, containerWrapper: container })
       console.log(`expandUnchanged=${expandUnchanged}: rendered OK`)
     } catch (e) {
       console.log(`expandUnchanged=${expandUnchanged}: THROWS ->`, (e as Error).message)
     }
   }

   Run it: bun repro.ts
4. opencodejr

   added

   reproduced

   on Oct 28, 2026
5. Tarquinen

   closed this as completedin #62241on Nov 6, 2026