Is it safe to compress changes?

[Bob Jarvis]

I seem to recall that in a long-ago version of Dolphin (2.x? 3.x?)
compressing changes could lead to problems. I don't recall the
specifics but I haven't compressed changes since, preferring to fall
back to the "save all packages, restart from a base image, load all
packages" scheme when I got tired of looking at a huge changes file.
So, is it safe to use Smalltalk compressSources in Dolphin XP? I'd
try finding out the hard way (my usual method of doing things) but,
just this once, I thought I'd ask first. Thanks.

[Ian Bartholomew]

Bob,

In the above you mention both "compress changes" and "compress sources" -
but I can't say I've ever seen a problem with either. FWIW my image set-up
script automatically performs a "compress changes" so I reckon you should be
safe.

If you just want to reduce the size of the image file I would recommend that
you just compress the change log though. This means that you retain
information about which methods come from the original installation and
which have been added later. Compressing the sources results in a new *.sml
file and this distinction, which can occasionally be useful, is lost.

Ian

In case anybody isn't sure of the difference....

compress changes goes through the changes log, removes all extraneous
information (doIts etc) and all but the current definition of changed
methods and classes. You are left with a *.sml file containing the original
method definitions and *.chg file containing the current definitions for any
changed/added methods.

compress sources removes everything from *.chg and rewrites the *.sml file
so that it contains the current definition of all the methods in the image.

[Bill Schwab]

Bob,

The problem was that the older versions didn't automatically save the image
after compressing the changes, so one could end up with compressed changes
and an image that didn't match =:0 AFAIK, it's fine now. The info on the
wiki re archiving image/changes/sources together is still good reading. Of
course, in compressing, you lose past versions of code and (more recently)
view resources.

Have a good one,

Bill

--
Wilhelm K. Schwab, Ph.D.
bi...@anest4.anest.ufl.edu