Interleaved search index incorrectly requires parent key in token_column_list

[silas]

Interleaved search indexes incorrectly require the parent key in the token_column_list parameter.

CREATE TABLE one (
  one_id STRING(MAX) NOT NULL
)
PRIMARY KEY (one_id);

CREATE TABLE two (
  one_id       STRING(MAX) NOT NULL,
  two_id       STRING(MAX) NOT NULL,
  title        STRING(MAX),
  title_tokens TOKENLIST AS (TOKENIZE_SUBSTRING(title)) HIDDEN
)
PRIMARY KEY (one_id, two_id),
INTERLEAVE IN PARENT one;

Creating the valid search index fails:

CREATE SEARCH INDEX search_title ON two (title_tokens)
  PARTITION BY one_id,
  INTERLEAVE IN one
  OPTIONS (sort_order_sharding = true);

With the following error:

code = FailedPrecondition desc = Index search_title does not reference index parent key column one_id.

You can work around this in the emulator by adding the column, but this won't work in Google Cloud:

CREATE SEARCH INDEX search_title ON two (one_id, title_tokens)
  PARTITION BY one_id,
  INTERLEAVE IN one
  OPTIONS (sort_order_sharding = true);