[1.0-rc1] Alter retention policy does not accept "default" with "shard duration"

[kostasb]

ALTER RETENTION POLICY throws a parsing error if shard duration and default co-exist in the statement.

As a result of the combination of this and issue 7150 which describes that the ALTER statement resets shard duration when not explicitly defined, the impact is :

• two ALTER statements are needed to set a new default RP with custom shard duration (workaround: set all parameters during CREATE RETENTION POLICY)
• in order to switch the default RP while maintaining a custom shard duration, the ALTER ... default statement needs to go first, followed by ALTER ... shard duration.
  If the statements are given in the opposite order, the custom shard duration will be overwritten.
• the ALTER statement as documented in 1.0 docs does not work.

InfluxDB shell version: 1.0.0~rc1

> create database mytest

> show retention policies on mytest
name    duration    shardGroupDuration  replicaN    default
autogen 0       168h0m0s        1       true

> use mytest
Using database mytest

> alter retention policy autogen on mytest duration 720h replication 1 shard duration 168h default
ERR: error parsing query: found DEFAULT, expected ; at line 1, char 90

> alter retention policy autogen on mytest duration 720h replication 1 shard duration 168h

> show retention policies on mytest
name    duration    shardGroupDuration  replicaN    default
autogen 720h0m0s    168h0m0s        1       true

> alter retention policy autogen on mytest duration 720h replication 1 default

> show retention policies on mytest
name    duration    shardGroupDuration  replicaN    default
autogen 720h0m0s    24h0m0s         1       true

[jwilder]

@jsternberg Can you take a look?

[beckettsean]

@rkuchan possible docs change, let's watch this issue

[jsternberg]

This definitely just looks like a parsing error. I'm investigating now.

[jsternberg]

Fixed via #7219.