[dvipdfmx] Intermittent xdvipdfmx failure

[Tim Eyre]

On Tue, 26 Jan 2021 at 10:34, Philip Taylor
<P.Taylor at hellenic-institute.uk> wrote:
> Oh.  Sigh.  That suggests that the Win-7 & Win-10 CMD interpreters differ in some strange way.  I do not have Win-10, so cannot investigate I am afraid [1].  Can you send some sort of log/trace/whatever showing how it fails under Win-10 ?
[...]
> OK, are you setting SOURCE_DATE_EPOCH=1456304492 ?  If not (or at least, if not consistently setting it to some valid value), then there will be inconsistent file sizes, as reported by Hirata-san.

I didn't set SOURCE_DATE_EPOCH=1456304492 on my first attempt. After
setting that environment variable, the test.pdf emitted by xdvipdfmx
was the same length (394511) over 16,000 iterations. This was with
Kakuto-san's version of xdvipdfmx.

Console log from the failing batch job below:

c:\work\xdvipdfmx_debug\tmp>dir /b
test.tex
test2.bat

c:\work\xdvipdfmx_debug\tmp>cat test2.bat
@echo off
SETLOCAL

SET SOURCE_DATE_EPOCH=1456304492

xetex -no-pdf test.tex

FOR /L %%n in (1,1,1073741823) DO (xdvipdfmx -q -z 0 test.xdv && FOR
%%m in (test.pdf) DO ECHO Iteration %%n: %%~zm bytes && IF %%~zm ==
393023 (DEL good.pdf && REN %%m good.pdf) ELSE (REN %%m bad.pdf &&
PAUSE)) || ECHO Failed with error %ERRORLEVEL% && PAUSE

c:\work\xdvipdfmx_debug\tmp>test2.bat
This is XeTeX, Version 3.14159265-2.6-0.999992 (TeX Live 2020/W32TeX)
(preloaded format=xetex)
 restricted \write18 enabled.
entering extended mode
(./test.tex
Underfull \vbox (badness 10000) has occurred while \output is active [1]
Underfull \vbox (badness 10000) has occurred while \output is active [2]
Underfull \vbox (badness 10000) has occurred while \output is active [3]
Underfull \vbox (badness 10000) has occurred while \output is active [4]
Underfull \vbox (badness 10000) has occurred while \output is active [5]
Underfull \vbox (badness 10000) has occurred while \output is active [6]
Underfull \vbox (badness 10000) has occurred while \output is active [7]
[8] )
(see the transcript file for additional information)
Output written on test.xdv (8 pages, 142320 bytes).
Transcript written on test.log.
Iteration 1: 394511 bytes
Press any key to continue . . .
Iteration 2: 394511 bytes
A duplicate file name exists, or the file
cannot be found.
Failed with error 0
Press any key to continue . . .
Iteration 3: 394511 bytes
A duplicate file name exists, or the file
cannot be found.
Failed with error 0
Press any key to continue . . .
Iteration 4: 394511 bytes
A duplicate file name exists, or the file
cannot be found.
Failed with error 0
Press any key to continue . . .
Terminate batch job (Y/N)? y