Make `swh db init` command work *properly* with the --dbname option

This allows to run the command swh db init --dname DBURI without giving a configuration file AND properly set the db version, which can be handy some times when testing.

Note that this may not work for all swh packages, when the postgresql backend for the given swh package needs more configuration entries than just the psql connection string.

This more or less drop support for "old style" db sql init scripts:

• the swh db init will still work for an 'old style' package (in which the sql init scripts do create dbversio table and initialize it) but will display an error message,
• the --initial-version option has been dropped, since this made sense only for old style packages,
• the test data 'cli_new' has been renamed as 'cli' (in place of the previous "old style" one)

swh/core/cli/db.py

@@ -140,16 +140,13 @@ def db_init_admin(module: str, dbname: str) -> None:
     help="Database flavor.",
     default=None,
 )
-@click.option(
-    "--initial-version", help="Database initial version.", default=1, show_default=True
-)
 @click.pass_context
-def db_init(ctx, module, dbname, flavor, initial_version):
+def db_init(ctx, module, dbname, flavor):
     """Initialize a database for the Software Heritage <module>.
 
-    The database connection string comes from the configuration file (see
-    option ``--config-file`` in ``swh db --help``) in the section named after
-    the MODULE argument.
+    The database connection string can come from the --db-name option, or from
+    the configuration file (see option ``--config-file`` in ``swh db --help``)
+    in the section named after the MODULE argument.
 
     Example::
 
@@ -164,9 +161,8 @@ def db_init(ctx, module, dbname, flavor, initial_version):
         \b
         $ swh db -C conf.yml init storage  # or
         $ SWH_CONFIG_FILENAME=conf.yml swh db init storage
-
-    Note that the connection string can also be passed directly using the
-    '--db-name' option, but this usage is about to be deprecated.
+        $ # or
+        $ swh db init --db-name postgresql://user:passwd@pghost:5433/swh-storage storage
 
     """
     from swh.core.db.db_utils import (
@@ -194,54 +190,56 @@ def db_init(ctx, module, dbname, flavor, initial_version):
     initialized, dbversion, dbflavor = populate_database_for_package(
         module, dbname, flavor
     )
-    if dbversion is None:
-        if cfg is not None:
-            # db version has not been populated by sql init scripts (new style),
-            # let's do it; instantiate the data source to retrieve the current
-            # (expected) db version
-            datastore_factory = getattr(import_swhmodule(module), "get_datastore", None)
-            if datastore_factory:
-                datastore = datastore_factory(**cfg)
-                if not hasattr(datastore, "current_version"):
-                    logger.warning(
-                        "Datastore %s does not declare the "
-                        "'current_version' attribute",
-                        datastore,
-                    )
-                else:
-                    code_version = datastore.current_version
-                    logger.info(
-                        "Initializing database version to %s from the %s datastore",
-                        code_version,
-                        module,
-                    )
-                    swh_set_db_version(dbname, code_version, desc="DB initialization")
+    if dbversion is not None:
+        click.secho(
+            "ERROR: the database version has been populated by sql init scripts. "
+            "This is now deprecated and should not happen any more"
+        )
+    else:
+        # db version has not been populated by sql init scripts (new style),
+        # let's do it; instantiate the data source to retrieve the current
+        # (expected) db version
+        if cfg is None:
+            cfg = {"cls": "postgresql", "db": dbname}
+        datastore_factory = getattr(import_swhmodule(module), "get_datastore", None)
+        if datastore_factory:
+            datastore = datastore_factory(**cfg)
+            if not hasattr(datastore, "current_version"):
+                logger.warning(
+                    "Datastore %s does not declare the " "'current_version' attribute",
+                    datastore,
+                )
+            else:
+                code_version = datastore.current_version
+                logger.info(
+                    "Initializing database version to %s from the %s datastore",
+                    code_version,
+                    module,
+                )
+                swh_set_db_version(dbname, code_version, desc="DB initialization")
 
     dbversion = get_database_info(dbname)[1]
     if dbversion is None:
-        logger.info(
-            "Initializing database version to %s "
-            "from the command line option --initial-version",
-            initial_version,
+        click.secho(
+            "ERROR: database for {} {}{} BUT db version could not be set".format(
+                module,
+                "initialized" if initialized else "exists",
+                f" (flavor {dbflavor})" if dbflavor is not None else "",
+            ),
+            fg="red",
+            bold=True,
+        )
+    else:
+        click.secho(
+            "DONE database for {} {}{} at version {}".format(
+                module,
+                "initialized" if initialized else "exists",
+                f" (flavor {dbflavor})" if dbflavor is not None else "",
+                dbversion,
+            ),
+            fg="green",
+            bold=True,
         )
-        swh_set_db_version(dbname, initial_version, desc="DB initialization")
-
-    dbversion = get_database_info(dbname)[1]
-    assert dbversion is not None
-
-    # TODO: Ideally migrate the version from db_version to the latest
-    # db version
-
-    click.secho(
-        "DONE database for {} {}{} at version {}".format(
-            module,
-            "initialized" if initialized else "exists",
-            f" (flavor {dbflavor})" if dbflavor is not None else "",
-            dbversion,
-        ),
-        fg="green",
-        bold=True,
-    )
 
     if flavor is not None and dbflavor != flavor:
         click.secho(