# Buggy code
def get_or_create_union_type(
    schema: s_schema.Schema,
    components: Iterable[ObjectType],
    *,
    opaque: bool = False,
    module: Optional[str] = None,
) -> Tuple[s_schema.Schema, ObjectType, bool]:
    type_id, name = s_types.get_union_type_id(
        schema,
        components,
        opaque=opaque,
        module=module,
    )

    objtype = schema.get_by_id(type_id, None, type=ObjectType)
    created = objtype is None
    if objtype is None:
        components = list(components)

        std_object = schema.get("std::BaseObject", type=ObjectType)

        schema, objtype = std_object.derive_subtype(
            schema,
            name=name,
            attrs=dict(
                id=type_id,
                union_of=so.ObjectSet.create(schema, components),
                is_opaque_union=opaque,
                abstract=True,
                final=True,
            ),
        )

        if not opaque:
            schema = sources.populate_pointer_set_for_source_union(
                schema,
                cast(List[sources.Source], components),
                objtype,
                modname=module,
            )

    return schema, objtype, created


# Traceback (AttributeError)
ERROR: InternalServerError: 'UnionType' object has no attribute 'get_name'
Hint: This is most likely a bug in EdgeDB. Please consider opening an issue ticket at https://github.com/edgedb/edgedb/issues/new?template=bug_report.md
Server traceback:
Traceback (most recent call last):
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/server/procpool/worker.py", line 75, in worker
res = await meth(*args)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/server/compiler/compiler.py", line 1808, in compile_eql_tokens
return self._compile(ctx=ctx, tokens=eql_tokens)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/server/compiler/compiler.py", line 1442, in _compile
comp: dbstate.BaseQuery = self._compile_dispatch_ql(ctx, stmt)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/server/compiler/compiler.py", line 1365, in _compile_dispatch_ql
return self._compile_ql_migration(ctx, ql)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/server/compiler/compiler.py", line 794, in _compile_ql_migration
target_schema = s_ddl.apply_sdl(
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/schema/ddl.py", line 371, in apply_sdl
ddl_stmts = s_decl.sdl_to_ddl(current_schema, documents)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/declarative.py", line 230, in sdl_to_ddl
trace_dependencies(decl_ast, ctx=ctx)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/functools.py", line 875, in wrapper
return dispatch(args[0].__class__)(*args, **kw)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/declarative.py", line 499, in trace_default
_register_item(node, ctx=ctx)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/declarative.py", line 623, in _register_item
trace_dependencies(cmd, ctx=ctx)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/functools.py", line 875, in wrapper
return dispatch(args[0].__class__)(*args, **kw)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/declarative.py", line 443, in trace_ConcretePointer
_register_item(
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/declarative.py", line 638, in _register_item
tdeps = qltracer.trace_refs(
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/tracer.py", line 162, in trace_refs
trace(qltree, ctx=ctx)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/functools.py", line 875, in wrapper
return dispatch(args[0].__class__)(*args, **kw)
File "/usr/lib/x86_64-linux-gnu/edgedb-server-1-alpha6/lib/python3.8/site-packages/edb/edgeql/tracer.py", line 653, in trace_Select
ctx.path_prefix = tip.get_name(ctx.schema)
AttributeError: 'UnionType' object has no attribute 'get_name'

# Fixed code
def get_or_create_union_type(
    schema: s_schema.Schema,
    components: Iterable[ObjectType],
    *,
    opaque: bool = False,
    module: Optional[str] = None,
) -> Tuple[s_schema.Schema, ObjectType, bool]:
    name = s_types.get_union_type_name(
        (c.get_name(schema) for c in components),
        opaque=opaque,
        module=module,
    )

    objtype = schema.get(name, default=None, type=ObjectType)
    created = objtype is None
    if objtype is None:
        components = list(components)

        std_object = schema.get("std::BaseObject", type=ObjectType)

        schema, objtype = std_object.derive_subtype(
            schema,
            name=name,
            attrs=dict(
                union_of=so.ObjectSet.create(schema, components),
                is_opaque_union=opaque,
                abstract=True,
                final=True,
            ),
        )

        if not opaque:
            schema = sources.populate_pointer_set_for_source_union(
                schema,
                cast(List[sources.Source], components),
                objtype,
                modname=module,
            )

    return schema, objtype, created