MySQL Bugs: #36151: Proxy parser.lua -- get_tables function works unexpectedly on subsequent uses

Bug #36151	Proxy parser.lua -- get_tables function works unexpectedly on subsequent uses
Submitted:	16 Apr 2008 21:18
Reporter:	Lachlan Mulcahy
Status:	Verified
Category:	Proxy: Scripts	Severity:	S3 (Non-critical)
Version:	0.6.1, 0.7.1	OS:	Any
Assigned to:	Diego Medina	Target Version:
Triage:	D2 (Serious) / R1 (None/Negligible) / E1 (None/Negligible)

Description:
When using the get_tables function on the parser.lua script bundled with proxy, running
the parser more than once gives incorrect/unexpected results.

How to repeat:
Create bugtest.lua:

function read_query ( packet ) 

            local query = "DROP TABLE t"

            local tk = require('proxy.tokenizer')
            local pr = require('proxy.parser')
            local tokens = tk.tokenize(query)

            local tbls = pr.get_tables(tokens)

            for k, v in pairs(tbls) do
                print(k.." => "..v)
            end

            tbls = pr.get_tables(tokens)

            for k, v in pairs(tbls) do
                print(k.." => "..v)
            end

            return proxy.PROXY_SEND_QUERY

end

shell> mysql-proxy --proxy-lua-script=bugtest.lua

Connect to the proxy, issue some query and watch the output.

Suggested fix:
Initialise the ddl_type variable in the get_tables function to avoid subsequent
executions using the old value...

Apply this diff to ./lib/proxy/parser.lua:

40a41
>     local ddl_type = nil

This problem seems to persist in version 0.7.1 and trunk, but I'm confused about the
output.
Even with the patch there seems to be a problem, but I can't quite figure out what I'm
missing off-hand.

Needs test case.