The following steps cause a crash in TeXmacs and corrupt $TEXMACS_HOME_PATH/system/interactive.scm, which thereafter prevents TeXmacs from starting.

1) Insert a drawing
2) Select the line tool
3) Click the icon to set the line's dash style
4) Under "Unit", click "Other"
5) Leave at least one of the two fields open and click OK

The terminal shows this error:

Backtrace:
In unknown file:
   ?: 0* [#<procedure #f ()>]
   ?: 1* [graphics-set-dash-style-unit* "1pt" #<eof>]
In /home/jeroen/texmacs/master/share/TeXmacs/progs/graphics/graphics-main.scm:
 944: 2  [#<procedure #f (var val)> "gr-dash-style-unit" {(tuple "1pt" #<eof>)}]
In /home/jeroen/texmacs/master/share/TeXmacs/progs/graphics/graphics-utils.scm:
   ...
 359: 3  [path-insert-with (0 0 6) "gr-dash-style-unit" {(tuple "1pt" #<eof>)}]

/home/jeroen/texmacs/master/share/TeXmacs/progs/graphics/graphics-utils.scm:359:14: In procedure path-insert-with in expression (path-insert-with p var ...):
/home/jeroen/texmacs/master/share/TeXmacs/progs/graphics/graphics-utils.scm:359:14: Wrong type argument in position 3: (tuple "1pt" #<eof>)

After closing TeXmacs, it will no longer start, since interactive.scm is corrupted by the lines

 (graphics-set-dash-style-unit*
   (("0" . "1pt") ("1" . #<eof>)))

Removing these lines fixes the problem.

This bug is related to bug #58812.