[jira] [Created] (ZOOKEEPER-5105) zkCli addWatch reuses the mode of a previous invocation when -m is omitted

["Jialin Chen (Jira)" <ji...@apache.org>]

Jialin Chen created ZOOKEEPER-5105:
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             Summary: zkCli addWatch reuses the mode of a previous invocation when -m is omitted
                 Key: ZOOKEEPER-5105
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-5105
             Project: ZooKeeper
          Issue Type: Bug
          Components: java client
    Affects Versions: 3.10.0, 3.8.7, 3.9.6
            Reporter: Jialin Chen


zkCli keeps a single instance of each CLI command for the whole session, and {{AddWatchCommand.parse()}} only assigns the {{mode}} field when {{-m}} is given. After an {{addWatch -m PERSISTENT ...}}, every later {{addWatch}} without {{-m}} in the same session registers a {{PERSISTENT}} watch instead of the default {{PERSISTENT_RECURSIVE}} that the usage text announces ("default is PERSISTENT_RECURSIVE").

Steps to reproduce (standalone server built from master at 48f7cb00e):
{noformat}
[zk: localhost:22181(CONNECTED) 0] create /w1 x
[zk: localhost:22181(CONNECTED) 1] create /w2 x
[zk: localhost:22181(CONNECTED) 2] addWatch -m PERSISTENT /w1
[zk: localhost:22181(CONNECTED) 3] addWatch /w2
[zk: localhost:22181(CONNECTED) 4] create /w2/c x
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/w2 zxid: 35
{noformat}

Expected: {{addWatch /w2}} registers a persistent recursive watch, so creating {{/w2/c}} fires {{NodeCreated path:/w2/c}}. This is what a fresh session gets:
{noformat}
[zk: localhost:22181(CONNECTED) 0] create /w3 x
[zk: localhost:22181(CONNECTED) 1] addWatch /w3
[zk: localhost:22181(CONNECTED) 2] create /w3/c x
WatchedEvent state:SyncConnected type:NodeCreated path:/w3/c zxid: 38
{noformat}

Actual: the watch on {{/w2}} is a plain persistent watch, so only {{NodeChildrenChanged path:/w2}} fires.

The behaviour dates back to the introduction of the command in ZOOKEEPER-1416 (3.6.0). {{ReconfigCommand.parse()}} already resets its per-invocation fields for the same reason; {{AddWatchCommand.parse()}} should fall back to the default mode when {{-m}} is absent.



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