Windows Doesn’t Like Trailing Periods/Dots

Just in case the mystery of Subversion and trailing spaces wasn’t enough for you here’s another one. On one of the Windows workstations TortoiseSVN would continue to show a change in a folder where no changes had been made. So we started playing with this to figure out what was going on.

I did the most obvious thing first, I ran svn update on the folder. This brought everything up to date and the icon overlay would go green for about three seconds and then turn red again. I did this three times in a row. The results were the same every time, green for a few seconds and then red. Next we started a commit to see what Subversion thought had changed. It indicated that there was one directory (called misc) that had changed. But nothing in the folder had changed.

Once again it took looking that directory name for a few minutes before went and compared it a checkout of the same repository on a unix system. Then the light bulb went on! In the repository the directory name had a period as the last character.

This Windows XP system didn’t like seeing a dot as the last character in a directory name and so it removed it. This showed up as a change to Subversion. We’d run svn update and it would restore the directory with the period, which was fine for a couple of seconds which was how long Windows took to notice it and change the directory name. So we were chasing our own tail for awhile.

I had no idea that Windows XP had a feature that automatically changed the name of a folder. What a completely annoying "feature".

The lesson here is that in at least some circumstances Windows XP doesn’t live having a trailing period/dot in a directory name and will remove it for you automatically.