When the debugger exits now it produces an <endsession> tag that informs
redis-cli (or other debugging clients) that the session terminated.
This way the client knows there is yet another reply to read (the one of
the EVAL script itself), and can switch to non-debugging mode ASAP.
It's handly to just eval "5+5" without the return and see it printed on
the screen as result. However prepending "return" does not always result
into valid Lua code. So what we do is to exploit a common Lua community
trick of trying to compile with return prepended, and if compilation
fails then it's not an expression that can be returned, so we try again
without prepending "return". Works great apparently.
Arguments arity and arguments type error of redis.call() were not
reported correctly to Lua, so the command acted in this regard like
redis.pcall(), but just for two commands. Redis.call() should always
raise errors instead.
Currently this feature is only accessible via DEBUG for testing, since
otherwise depending on the instance configuration a given script works
or is broken, which is against the Redis philosophy.
By calling redis.replicate_commands(), the scripting engine of Redis
switches to commands replication instead of replicating whole scripts.
This is useful when the script execution is costly but only results in a
few writes performed to the dataset.
Morover, in this mode, it is possible to call functions with side
effects freely, since the script execution does not need to be
deterministic: anyway we'll capture the outcome from the point of view
of changes to the dataset.
In this mode math.random() returns different sequences at every call.
If redis.replicate_commnads() is not called before any other write, the
command returns false and sticks to whole scripts replication instead.
Rationale is that when re-entering, it is likely due to Lua debugging
hooks. Returning an error will be ignored in most cases, going totally
unnoticed. With the log at least we leave a trace.
Related to issue #2302.
A few people have written custom C commands because bit
manipulation isn't exposed through Lua. Let's give
them Mike Pall's bitop.
This adds bitop 1.0.2 (2012-05-08) from http://bitop.luajit.org/
bitop is imported as "bit" into the global namespace.
New Lua commands: bit.tobit, bit.tohex, bit.bnot, bit.band, bit.bor, bit.bxor,
bit.lshift, bit.rshift, bit.arshift, bit.rol, bit.ror, bit.bswap
Verification of working (the asserts would abort on error, so (nil) is correct):
127.0.0.1:6379> eval "assert(bit.tobit(1) == 1); assert(bit.band(1) == 1); assert(bit.bxor(1,2) == 3); assert(bit.bor(1,2,4,8,16,32,64,128) == 255)" 0
(nil)
127.0.0.1:6379> eval 'assert(0x7fffffff == 2147483647, "broken hex literals"); assert(0xffffffff == -1 or 0xffffffff == 2^32-1, "broken hex literals"); assert(tostring(-1) == "-1", "broken tostring()"); assert(tostring(0xffffffff) == "-1" or tostring(0xffffffff) == "4294967295", "broken tostring()")' 0
(nil)
Tests also integrated into the scripting tests and can be run with:
./runtest --single unit/scripting
Tests are excerpted from `bittest.lua` included in the bitop distribution.
