Subj : fseditor.js: don't dereference line[l+1] after splice in unwrap_line
To   : GitLab note in main/sbbs
From : Steven Philley
Date : Sat Sep 12 2026 05:10:15

https://gitlab.synchro.net/main/sbbs/-/merge_requests/731#note_10344

@Deuce Thanks for trying that — you're right that the 90-char word → delete-to-79 path does not hit the crash.

The TypeError only happens when **unkludge** consumes the entire next line and splices it out while that next line is the **last** line, then the loop continues into `line[l+1].text`.

Minimal state (80-col, usable width 79):

* `line[0]`: 70 chars, `kludged=true` (mid-word wrap)
* \- `line[1]`: last line, short no-whitespace suffix that fits in the remaining space (e.g. `XYZTAIL`)

Without the guard after unkludge: `TypeError: Cannot read properties of undefined (reading 'text')`.

With the MR guard `if(line[l+1]==undefined) break;`): joins to one line, no throw.

A long unbroken word that you then shorten to 79 never leaves a kludged line whose unkludge splice removes the final line, so it won't throw — sorry the earlier interactive steps pointed at the wrong path.

Happy to walk a jsexec/unit harness if that's easier than reproducing inside the full editor.
--- SBBSecho 3.37-Linux
 * Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

.