Multi-stage $ref doesn't work with jsonschema version 3.0.1 - jsonschema

Question

It seems that jsonschema version 3.0.1 does not accept multi-stage schema using $refs (while it works with jsonschema version 2.6.0).
I have to make it work under several module versions simply because my code will be running on different computers with different environments.
I verified my jsons on https://www.jsonschemavalidator.net/ (thanks for this link found in another StackOverflow question).
I Tried :
jsonschema -i myjson.json noRefs.schema.json --> 2.6.0 = OK, 3.0.1 OK
jsonschema -i myjson.json usingRefs.schema.json --> 2.6.0 = OK, 3.0.1 KO
Note :
Both *.schema.json worked on https://www.jsonschemavalidator.net/
File myjson.json :
{
"TopProperty" : {
"LowerProperty" : {"toto" : "plop"}
}
}
File noRefs.schema.json :
{
"type": "object",
"properties": {
"TopProperty": {"$ref": "#/schemaTopProperty"}
},
"schemaTopProperty": {
"$id": "schemaTopProperty",
"type": "object",
"properties": {
"LowerProperty": {
"type": "object",
"properties": {
"toto": {"type": "string"}
}
}
}
}
}
File usingRefs.schema.json :
{
"type": "object",
"properties": {
"TopProperty": {"$ref": "#/schemaTopProperty"}
},
"schemaTopProperty": {
"$id": "schemaTopProperty",
"type": "object",
"properties": {
"LowerProperty": {
"type": "object",
"properties": {
"toto": {"$ref": "#/justAString"}
}
}
}
},
"justAString": {
"$id": "justAString",
"type": "string"
}
}
Error message received :
Traceback (most recent call last):
File "/usr/bin/jsonschema", line 11, in <module>
sys.exit(main())
File "/usr/lib/python2.7/site-packages/jsonschema/cli.py", line 67, in main
sys.exit(run(arguments=parse_args(args=args)))
File "/usr/lib/python2.7/site-packages/jsonschema/cli.py", line 78, in run
for error in validator.iter_errors(instance):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 274, in properties
schema_path=property,
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 339, in descend
for error in self.iter_errors(instance, schema):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 251, in ref
for error in validator.descend(instance, resolved):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 339, in descend
for error in self.iter_errors(instance, schema):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 274, in properties
schema_path=property,
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 339, in descend
for error in self.iter_errors(instance, schema):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 73, in items
for error in validator.descend(item, items, path=index):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 339, in descend
for error in self.iter_errors(instance, schema):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 274, in properties
schema_path=property,
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 339, in descend
for error in self.iter_errors(instance, schema):
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 323, in iter_errors
for error in errors:
File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 247, in ref
scope, resolved = validator.resolver.resolve(ref)
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 734, in resolve
return url, self._remote_cache(url)
File "/usr/lib/python2.7/site-packages/functools32/functools32.py", line 400, in wrapper
result = user_function(*args, **kwds)
File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 744, in resolve_from_url
raise exceptions.RefResolutionError(exc)
jsonschema.exceptions.RefResolutionError: unknown url type: schemaTopProperty

Answer 1

Edit: my previous answer was incorrect.
TL;DR: You have two options:
Remove the $id properties from the definitions
Use #/ in the $id properties (Example: {"$id": "#/justAString"})
Details:
The issue is with the IDs, up until draft-04, $ref and $id were treated at face value, nothing special, but starting with draft-06 these are uri-references, in which case, when descending into {"$id": "schemaTopProperty"}, resolving {"$ref": "justAString"} is no more looking for a fragment justAString at the root structure, but for /justAString under schemaTopProperty host, which is a remote reference.
Hence my solutions to either remove the $ids which cause the definitions to be URLs (hosts in fact), or to define the $ids as what they are, fragments in the current schema.