[v3] SyncError: Calling sync() from within a running loop #2133

---------------------------------------------------------------------------
SyncError                                 Traceback (most recent call last)
Cell In[102], line 7
      5 zix = zarr.array(ix, chunks=2)
      6 za = zarr.array(a, chunks=2)
----> 7 za.oindex[zix]  # will not load all zix into memory

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/indexing.py:845, in OIndex.__getitem__(self, selection)
    843 new_selection = ensure_tuple(new_selection)
    844 new_selection = replace_lists(new_selection)
--> 845 return self.array.get_orthogonal_selection(
    846     cast(OrthogonalSelection, new_selection), fields=fields
    847 )

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/array.py:1338, in Array.get_orthogonal_selection(self, selection, out, fields, prototype)
   1336     prototype = default_buffer_prototype()
   1337 indexer = OrthogonalIndexer(selection, self.shape, self.metadata.chunk_grid)
-> 1338 return sync(
   1339     self._async_array._get_selection(
   1340         indexer=indexer, out=out, fields=fields, prototype=prototype
   1341     )
   1342 )

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/sync.py:91, in sync(coro, loop, timeout)
     88 return_result = next(iter(finished)).result()
     90 if isinstance(return_result, BaseException):
---> 91     raise return_result
     92 else:
     93     return return_result

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/sync.py:50, in _runner(coro)
     45 """
     46 Await a coroutine and return the result of running it. If awaiting the coroutine raises an
     47 exception, the exception will be returned.
     48 """
     49 try:
---> 50     return await coro
     51 except Exception as ex:
     52     return ex

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/array.py:467, in AsyncArray._get_selection(self, indexer, prototype, out, fields)
    458     out_buffer = prototype.nd_buffer.create(
    459         shape=indexer.shape,
    460         dtype=out_dtype,
    461         order=self.order,
    462         fill_value=self.metadata.fill_value,
    463     )
    464 if product(indexer.shape) > 0:
    465     # reading chunks and decoding them
    466     await self.codec_pipeline.read(
--> 467         [
    468             (
    469                 self.store_path / self.metadata.encode_chunk_key(chunk_coords),
    470                 self.metadata.get_chunk_spec(chunk_coords, self.order, prototype=prototype),
    471                 chunk_selection,
    472                 out_selection,
    473             )
    474             for chunk_coords, chunk_selection, out_selection in indexer
    475         ],
    476         out_buffer,
    477         drop_axes=indexer.drop_axes,
    478     )
    479 return out_buffer.as_ndarray_like()

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/array.py:467, in <listcomp>(.0)
    458     out_buffer = prototype.nd_buffer.create(
    459         shape=indexer.shape,
    460         dtype=out_dtype,
    461         order=self.order,
    462         fill_value=self.metadata.fill_value,
    463     )
    464 if product(indexer.shape) > 0:
    465     # reading chunks and decoding them
    466     await self.codec_pipeline.read(
--> 467         [
    468             (
    469                 self.store_path / self.metadata.encode_chunk_key(chunk_coords),
    470                 self.metadata.get_chunk_spec(chunk_coords, self.order, prototype=prototype),
    471                 chunk_selection,
    472                 out_selection,
    473             )
    474             for chunk_coords, chunk_selection, out_selection in indexer
    475         ],
    476         out_buffer,
    477         drop_axes=indexer.drop_axes,
    478     )
    479 return out_buffer.as_ndarray_like()

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/indexing.py:813, in OrthogonalIndexer.__iter__(self)
    812 def __iter__(self) -> Iterator[ChunkProjection]:
--> 813     for dim_projections in itertools.product(*self.dim_indexers):
    814         chunk_coords = tuple(p.dim_chunk_ix for p in dim_projections)
    815         chunk_selection: tuple[Selector, ...] | npt.NDArray[Any] = tuple(
    816             p.dim_chunk_sel for p in dim_projections
    817         )

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/indexing.py:542, in BoolArrayDimIndexer.__iter__(self)
    539 for dim_chunk_ix in self.dim_chunk_ixs:
    540     # find region in chunk
    541     dim_offset = dim_chunk_ix * self.dim_chunk_len
--> 542     dim_chunk_sel = self.dim_sel[dim_offset : dim_offset + self.dim_chunk_len]
    544     # pad out if final chunk
    545     if dim_chunk_sel.shape[0] < self.dim_chunk_len:

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/array.py:899, in Array.__getitem__(self, selection)
    897     return self.vindex[cast(CoordinateSelection | MaskSelection, selection)]
    898 elif is_pure_orthogonal_indexing(pure_selection, self.ndim):
--> 899     return self.get_orthogonal_selection(pure_selection, fields=fields)
    900 else:
    901     return self.get_basic_selection(cast(BasicSelection, pure_selection), fields=fields)

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/array.py:1338, in Array.get_orthogonal_selection(self, selection, out, fields, prototype)
   1336     prototype = default_buffer_prototype()
   1337 indexer = OrthogonalIndexer(selection, self.shape, self.metadata.chunk_grid)
-> 1338 return sync(
   1339     self._async_array._get_selection(
   1340         indexer=indexer, out=out, fields=fields, prototype=prototype
   1341     )
   1342 )

File ~/Library/CloudStorage/Dropbox/src/zarr-python/src/zarr/core/sync.py:78, in sync(coro, loop, timeout)
     76     loop0 = asyncio.events.get_running_loop()
     77     if loop0 is loop:
---> 78         raise SyncError("Calling sync() from within a running loop")
     79 except RuntimeError:
     80     pass

SyncError: Calling sync() from within a running loop