Now the test actually has a recording and garbage with matching files.
This caught a few problems in the upgrade procedure:
* it didn't work with foreign keys enabled because the new recording
table was set up after the new camera table, and the old recording
table was destroyed after the old camera table. And now I enable
foreign keys all the time. Reorder the procedure to fix.
* the pathname manipulation in the v2 to v3 procedure was incorrect
since my introduction of nix because I gave it a &[u8] with the
trailing nul, where I should have used CStr::from_bytes_with_nul.
* it wasn't removing garbage files. It'd be most natural to do this
in the v2 to v3 upgrade (with the rename) but I historically removed
the table when upgrading to v2. I can't redefine the schema now, so
do it unnaturally.
I'm considering also renaming all uuid-like files on upgrade to v4/v5
to clean up this mess automatically for installations that have
already done this upgrade.
This is mostly just "cargo fix --edition" + Cargo.toml changes.
There's one fix for upgrading to NLL in db/writer.rs:
Writer::previously_opened wouldn't build with NLL because of a
double-borrow the previous borrow checker somehow didn't catch.
Restructure to avoid it.
I'll put elective NLL changes in a following commit.
In hindsight, the "post_tx" step in the upgrade process introduced in
e7f5733 doesn't make sense. If the procedure fails at this stage, nothing says
it still needs to be completed. If the sample file dirs have to be updated
after the database, then there should be another database version to mark that
it's fully completed, and indeed that's the purpose version 3 serves. So get
rid of the Upgrader trait and just go back to a simple run function per
version.
In the case of the sample file dir metadata, it actually can happen before the
database transaction; the stuff written to the database later just needs to be
consistent with what it finds if there's an existing metadata file from a
half-completed update.
For safety, ensure there are no unexpected directory contents before
upgrading 1->2, and ensure the metadata matches before upgrading 2->3.
