more precisely, fix the way that the drracket test utilities
deal with the test suite so that when certain prefs are
initialized (as part of a test suite startup of drracket),
they actually get initialized properly (this was broken for
preferences whose value gets read particularly early)
Then use that to disable autosaving in the no-write-and-frame-leak.rkt
test
Fallback checked original module only if `deserialize-info` was
missing, but it's possible to have a mixture of `deserialize-info`
and original-module exports.
This change is slightly incompatible, because `serializable-struct`,
`define-serializable-struct`, and `define-serializable-class` no
longer `provide` and identifier that they used to. Instead, the identifier
is provided by a `deserialize-info` submodule.
The deserializer looks for a `deserialize-info` submodule, and then
falls back to using a module if the submodule is not available.
Depth 0 is the same as `--html`, depth 1 is the same as `--htmls`,
and higher depths cause sections and subsections to be rendered
into separate directories when they have their own pages.
Previously, (check-exn exn? 'foo) would pass even though 'foo is not a
thunk. Now it raises an exn:fail:contract? exception.
Previously, (check-not-exn 'foo) would produce a check failure. Now it
raises an exn:fail:contract? exception.
Downloaded files are keyed on the source URL and checksum, and the
cache is used only when a checksum is known.
The cache addresses two situations:
* when installing many packages over an unreliable connection,
the cache effectively lets a retry pick up where a previous
attempt failed
* when creating clean builds frequently, the downloads from a
previous build can be reused (as long as the package's checksum
does not change)
The cache location and limits are configurable, and they default to
a subdirectory in the user's add-ons directory (not version-specific),
1024 files, and 64 MB.
If a failure happens during staging (checksum and unpackaging) of a
package that has an entry in the cache, the entry is removed. The
file-cache library, meanwhile, implements a limit on the cache size
and defends against uncooperative filesystems.
