I think this got fixed in the 9.1.0 release so I am closing this report.

comment #2:

> All filesystems on this Ubuntu machine are ext4, and they are on a solid state disk.
>

Do you use some special mount options? E.g. do you use "noatime"?

Dmitri.
--

When I copy the exact code from comment #3 into an m-file (I named it demo_quiver.m) and then run it on my machine, I do get the following error:

>> demo_quiver

quiver example 1:
 clf;
 [x,y] = meshgrid (1:2:20);
 h = quiver (x,y, sin (2*pi*x/10), sin (2*pi*y/10));
 title ("quiver() plot w/arrowheads (default)");

error: 'scripts' undefined near line 3, column 1
error: called from
    demo_quiver at line 3 column 21

This is a different error, than mentioned in comment #3.

When I instead copy the code from comment #3 directly into a (GUI) Octave console, then I see this error:

>> demo ("quiver", 1)
quiver example 1:
 clf;
 [x,y] = meshgrid (1:2:20);
 h = quiver (x,y, sin (2*pi*x/10), sin (2*pi*y/10));
 title ("quiver() plot w/arrowheads (default)");

>> ## In another terminal window, execute 'touch
>> scripts/plot/private/__quiver__.m
error: 'scripts' undefined near line 1, column 1
>> demo ("quiver", 1)
quiver example 1:
 clf;
 [x,y] = meshgrid (1:2:20);
 h = quiver (x,y, sin (2*pi*x/10), sin (2*pi*y/10));
 title ("quiver() plot w/arrowheads (default)");

>> quiver example 1:
error: quiver: U and V must be the same size
error: called from
    __quiver__ at line 67 column 9
    quiver at line 92 column 10
>>  clf;
>>  [x,y] = meshgrid (1:2:20);
>>  h = quiver (x,y, sin (2*pi*x/10), sin (2*pi*y/10));
>>  set (h, 'maxheadsize', 0.33);
>>

I hope this helps. Let me know if I should run different code on my machine.

in bug #40117 the specific issue could be triggered with:

demo ("quiver", 1)
## In another terminal window, execute 'touch scripts/plot/private/__quiver__.m
demo ("quiver", 1)
quiver example 1:
 clf;
 [x,y] = meshgrid (1:2:20);
 h = quiver (x,y, sin (2*pi*x/10), sin (2*pi*y/10));
 set (h, 'maxheadsize', 0.33);

quiver example 1: failed
'__add_datasource__' undefined near line 152 column 14

does that trigger an error on your system?

From the test:

   ## Update the secondary private function, attempting to avoid
   ## filesystem timestamp resolution problems.
   pause (1);

Which filesystem is used for your tmp directory? Does the test still fail if you increase the pause?