fix: Do not allow gaxOptions to be modified downstream

[danieljbruce]

Currently, #1372 has a failing test that produces an error that says Uncaught Error: Only one of retry or retryRequestOptions may be set. This code change allows that test to pass on the gcf-owl-bot PR branch.

Here is what currently happens:

The failing test uses a mock server that aborts the stream simulating a network error. This causes the client to retry. However, on the first call the client makes, options.gaxOptions gets passed down the stack at

nodejs-bigtable/src/table.ts

Line 906 in 8cc17aa

gaxOpts: options.gaxOptions,

and then modified so that the retry parameter of options.gaxOptions is defined having settings that match https://github.com/googleapis/nodejs-bigtable/blob/8cc17aa2acb2540b4c2b233c4245021815a7b030/src/v2/bigtable_client_config.json#L12-L20.. On the second call, options.gaxOptions is passed down the stack with the retry parameter defined this time and with the retryRequestOptions parameter attached at

nodejs-bigtable/src/index.ts

Line 859 in 8cc17aa

retryRequestOptions,

as well. This causes the error to be thrown that says Uncaught Error: Only one of retry or retryRequestOptions may be set.

What this fix does:

With this fix a copy of options.gaxOptions is passed down the call stack instead of options.gaxOptions itself. This means when the client retries, options.gaxOptions does not contain the retry parameter in the createReadStream function as this parameter is normally filled out much further down the stack. This means the error Uncaught Error: Only one of retry or retryRequestOptions may be set is not thrown.

Additional effects:

For retries, this means options.gaxOptions?.retry?.backoffSettings will be undefined at

nodejs-bigtable/src/table.ts

Lines 960 to 962 in 8cc17aa

	const backOffSettings =
	options.gaxOptions?.retry?.backoffSettings ||
	DEFAULT_BACKOFF_SETTINGS;

and retries will now use DEFAULT_BACKOFF_SETTINGS if backoff settings are not provided by the user. This is exactly what we want and is also the intent of the current code.