I didn't mention that when I reinstalled the project, I deleted all of the
xx files that Eclipse creates, including .project. I tried deleting it
again, to no avail.
I ended up fixing it, and I'll post the details here in case someone has a
similar problem. My project has a very large number of derived htm and
xml files. These were created after my project was created, and I never
refreshed the directories that contained them in Eclipse, so Eclipse did
not search for them when validating the project. When my system crashed
and I rebooted, something happened--either it lost the derived files, or I
inadvertently told it to refresh those directories, so it started scanning
for those files. I could tell from my task monitoring program what it was
doing, and I didn't want it to be validating all of those files, so I
killed Eclipse. I then changed the names of the containing directories by
putting a . in front of them; I assumed that Eclipse would then ignore
them (I'm running Windows, but Eclipse seems to ignore files/folders that
begin with .). I then restarted Eclipse, let it build, and then changed
the folder names back by removing the preceding dot. After this, Eclipse
was still building the php model every time I started, and taking ~20
minutes, so I posted here.
Eventually I noticed in my task monitoring program that Eclipse was
accessing a bunch of log files while it was building; I checked those log
files and discovered Java error printouts saying it couldn't find each of
the files in the directories that I thought I had hidden. That is,
Eclipse *didn't* ignore the .xx directories, and when I changed their
names back, it was then expecting all of the 20,000 files which were in
those directories. So when I started Eclipse, it was searching for each
of those files, not finding them, and then having to take the time to
print a couple hundred lines of error messages to log files. This is what
was consuming so much time.
The solution was for me to move the directories with all of the files out
of the project folder, then allow the project to build, then refresh those
directories so it was no longer expecting those folders, and then move the
folders back.
The lesson for anyone encountering a similar problem: check for log files
in the .metadata folder of your project directory; look for any repeated
actions (such as searching for files that don't exist) and then fix that
problem accordingly.
Obviously this problem is still prone to happen if I again inadvertently
refresh that directory and make Eclipse aware of those files. And if that
did happen, it would still take forever to build every time I start
Eclipse, because it would have to validate all of those files. The real
solution I need is a way to exclude specific files and directories from
being inspected by Eclipse... I'll address that in another post.