Non-zero minimum isolation connection pool size causes infinite function recursion (instant crash)

[EdNutting]

Hi,

When calling createClient, specifying a positive number for the isolationPoolOptions.min value causes an infinite recursion through the RedisClient constructor. It seems the initial create client calls the constructor, which checks the isolation pool options, which sees there are (say) 3 connections required, so it calls duplicate to create them. duplicate passes the same isolation options to the new RedisClient, which repeats the same check. Thus, infinite recursion.

I suggest that nested RedisClients created via duplicate should be given empty/undefined isolationPoolOptions. I think it is also surprising/unintuitive that calling duplicate on the top-level redis client would result in an entire new pool being created (i.e. doubling the number of connections) rather than just creating a single new (separate) connection.

Environment:

• Node.js Version: 16.4.2
• Redis Server Version: N/A
• Node Redis Version: 4.0.0-rc.2
• Platform: Windows 10

[leibale]

I think that .duplicate() should be changed to .duplicate(overrides: Partial<RedisClientOptions>), and the isolationPool.create function should use that to reset the isolationPoolOptions on the "duplicated" connections. What do you think?

[EdNutting]

That sounds like a reasonable solution to me.

The documentation for duplicate would need to make it really clear (for external callers) that not overriding the options will duplicate the isolation pool (i.e. up to double the number of underlying connections).