Merge version and version_sort columns

[david-crespo]

Semver version strings do not sort well lexicographically. In #2100 I hacked in DB sorting of system updates by version by adding a second column to sort by, version_sort:

omicron/common/src/sql/dbinit.sql

Lines 1575 to 1578 in 46f2295

	-- Unique semver version
	version STRING(64) NOT NULL, -- TODO: length
	-- version string with maj/min/patch 0-padded to be string sortable
	version_sort STRING(64) NOT NULL -- TODO: length

omicron/common/src/sql/dbinit.sql

Lines 1667 to 1672 in 46f2295

	-- The version of the system update this component's software came from.
	-- This may need to be nullable if we are registering components before we
	-- know about system versions at all
	system_version STRING(64) NOT NULL, -- TODO: length
	-- version string with maj/min/patch 0-padded to be string sortable
	system_version_sort STRING(64) NOT NULL, -- TODO: length

which uses left zero padding to make the versions sort almost correctly. (Technically, build and prerelease meta are not supposed to be sorted lexicographically, but we have decided to tolerate being wrong in this way for now.)

omicron/nexus/db-model/src/semver_version.rs

Lines 59 to 73 in 46f2295

	pub fn to_sortable_string(self) -> Result<String, external::Error> {
	let v = &self.0 .0;
	if v.major > MAX_VERSION_NUM
	|| v.minor > MAX_VERSION_NUM
	|| v.patch > MAX_VERSION_NUM
	{
	return Err(external::Error::InvalidValue {
	label: "version".to_string(),
	message: format!("Major, minor, and patch version must be less than {MAX_VERSION_NUM}"),
	});
	}
	let mut result =
	format!("{:0>8}.{:0>8}.{:0>8}", v.major, v.minor, v.patch);

However! These do not actually need to be two columns. I only did it that way because I didn't feel like figuring out how to deserialize the zero-padded version string back into a Semver::Version (built-in parse chokes on the zeros). The change that's required here is to update our ToSql for SemverVersion to do the zero-padding and the FromSql to remove the zero-padding before passing it to Semver::Version's parse.

omicron/nexus/db-model/src/semver_version.rs

Lines 86 to 110 in 46f2295

	impl<DB> ToSql<sql_types::Text, DB> for SemverVersion
	where
	DB: Backend<BindCollector = RawBytesBindCollector<DB>>,
	String: ToSql<sql_types::Text, DB>,
	{
	fn to_sql<'a>(
	&'a self,
	out: &mut serialize::Output<'a, '_, DB>,
	) -> serialize::Result {
	(self.0).0.to_string().to_sql(&mut out.reborrow())
	}
	}
	impl<DB> FromSql<sql_types::Text, DB> for SemverVersion
	where
	DB: Backend,
	String: FromSql<sql_types::Text, DB>,
	{
	fn from_sql(raw: RawValue<DB>) -> deserialize::Result<Self> {
	String::from_sql(raw)?
	.parse()
	.map(|s| SemverVersion(external::SemverVersion(s)))
	.map_err(|e| e.into())
	}
	}

That way, we do not have to generate a sortable string manually in the constructor.

omicron/nexus/db-model/src/system_update.rs

Lines 42 to 54 in 46f2295

	impl SystemUpdate {
	/// Can fail if version numbers are too high.
	pub fn new(
	version: external::SemverVersion,
	) -> Result<Self, external::Error> {
	let db_version = SemverVersion(version);
	Ok(Self {
	identity: SystemUpdateIdentity::new(Uuid::new_v4()),
	version: db_version.clone(),
	version_sort: db_version.to_sortable_string()?,
	})
	}
	}