This is a useful shorthand when generating SWHIDs in tests.

SWHID is deprecated; and CoreSWHID does not support qualifiers at all,
so RawExtrinsicMetadata no longer needs to check there are no qualifiers.

ExtendedSWHID can identify either a software artifact or an origin,
so we no longer need Union[SWHID, str].

Therefore, we no longer need the 'type' attribute, as it was only
used to tell when the target is a SWHID and when it's an origin URL.

It can be handy as a shortcut to build SWHID objects.

* Quote/unquote path
* Fix line parsing and serializing to properly handle None
* Fix error raised by check_visit/check_anchor

They were all very similar and only differ in what 'edge' cases they accept

Following the discussion on T3034, we decided to replace SWHID with
two or three classes:

* QualifiedSWHID to replace the existing SWHID (standard types + qualifiers)
* CoreSWHID, for "core SWHID" only (standard types + no qualifiers)
* ExtendedSWHID for internal use in Software Heritage (extra types + no qualifiers)

This commit adds the last one.

It also removes "ori" as a valid object type for CoreSWHID and
QualifiedSWHID, as it now only belongs in ExtendedSWHID.

And store their parsed values (CoreSWHID, tuple of ints, etc.) instead of string.

Following the discussion on T3034, we decided to replace SWHID with
two or three classes:

* QualifiedSWHID to replace the existing SWHID (standard types + qualifiers)
* CoreSWHID, for "core SWHID" only (standard types + no qualifiers)
* ExtendedSWHID for internal use in Software Heritage (extra types + no qualifiers)

This commit adds the second one

Following the discussion on T3034, we decided to replace SWHID with
two or three classes:

* QualifiedSWHID to replace the existing SWHID (standard types + qualifiers)
* CoreSWHID, for "core SWHID" only (standard types + no qualifiers)
* ExtendedSWHID for internal use in Software Heritage (extra types + no qualifiers)

Since migrating from SWHID will break existing code, this commit uses
the opportunity to modernize it a little, ie.:

* `keyword`-only constructor, to get rid of the hacky default values for
  `object_type` and `object_id`
* enum instead of strings for the object type
* `bytes` instead of an hex string for the object id
* rename `metadata` to `qualifiers`

Depending on the order in which tests are run, these tests may insert
lambdas with mocked blake2 functions in their closure to be inserted in
hashutil._blake2_hash_cache; causing all future tests to fail.

While this does not happen with the default order of tests, it does when
using pytest-xdist.

so it's kept up to date when evolutions are made in the model and thus
preventing swh-journal and swh-model to be unecessarly coupled.

Related to T2970.

They were mixed in with snapshot tests.

test_identifiers: Make sure that {directory,revision,release,snapshot}_identifier() doesn't just return a value from the dict.

For example, before this commit, you could replace the code of
revision_identifier() with this:

def release_identifier(release):
    return release.get("id", b"")

and all tests would still pass.

Before this change there was a lot of overlap between parse_swhid() and the
attrs-based validators in the SWHID class. Also, the validation implementation
in parse_swhid() was done by hand.

With this change the coarse-grained validation done by parse_swhid() is now
delegated to a regex. The semantic validation of SWHIDs is left to attrs
validators. The regex is also exposed as a module attribute, to be used by
client code that want to syntactically validate SWHIDs without necessarily
instantiate SWHID classes (we have several other modules doing that already,
and they are using slightly different hand-made regexs, which isn't great).

As part of this change we also clean up the use of ValidationError exceptions,
systematically passing the problematic parts of SWHID as arguments, and uniform
error messages.

This change also brings some speed up in SWHID parsing. On a benchmark parsing
~30 M valid SWHIDs, the previous implementation took ~3:06 minutes, the new one
~2:50 minutes, or a ~9% speedup.

Closes T2788

All reverse dependencies have been updated to avoid using it now, so it can now
be removed, paving the way to recycle it into an intrinsic identifier.

So parse_swhid raises a ValidationError when that is detected.

Related to T2769

Related to T2769

Related to T2769

This backwards-compatible change prepares the transition to give
RawExtrinsicMetadata an `id` field that is computed intrinsically from its
contents (using the HashableObject mixin).

that returns a value suitable for unicity constraints.

Motivation:

* this is somewhat more of a model concern than a journal/kafka
  concern IMO
* this is one step toward adding support for non-model objects in
  KafkaJournalWriter

Implementation of the unique_key methods comes from
`swh.journal.serializers.object_key`.

I created one in the wrong directory and didn't see the existing one.

Related to T2610

We may unknowingly pass naive datetimes to the storage through them,
causing the underlying DB to assign them a timezone that might not match
the actual one.

It already happens in swh.model and swh.loader.package tests.

Same as for the field data, it helps for code not yet migrated to use model
object.

It allows easy conversion of Union[ImmutableDict, Dict] to ImmutableDict.

So they are truly immutable now.

This will allow swh-storage to have a signature for *_metadata_add
that is consistent with other *_add endpoints.

Add a new extra_headers attribute on Revision and use it for computing
the revision's id instead of extract it from the metadata field.

Only accept (bytes, bytes) as extra_header.

Add a post init hook to Revision to initialize this new attribute from
given metadata, if any, for bw compat.

Also amend the revision_d hyptothesis strategy to generate extra_headers.

When Software Heritage persistent identifiers were introduced, they were not
yet abbreviated as SWHIDs.

Now that abbreviation is growing adoption, rename some functions and types in
swh.model.identifiers for consistency:

  - PersistentId -> SWHID

  - persistent_identifier -> swhid

  - parse_persistent_identifier -> parse_swhid

Backward compatibility with previous naming is maintained but deprecation
warnings are introduced to encourage the use of the new names.

Numerous variables in swh.model codebase have also been renamed accordingly.

Also rework and improve documentation.