Related to #4483. As suggested by @soloestoy, we can retrieve the SHA1
from the body. Given that in the new implementation using AUX fields we
ended copying around a lot to create new objects and strings, extremize
such concept and trade CPU for space inside the RDB file.
For example:
1. A module command called within a MULTI section.
2. A Lua script with replicate_commands() called within a MULTI section.
3. A module command called from a Lua script in the above context.
This fix, provided by Paul Kulchenko (@pkulchenko), allows the Lua
scripting engine to evaluate statements with a trailing comment like the
following one:
EVAL "print() --comment" 0
Lua can't parse the above if the string does not end with a newline, so
now a final newline is always added automatically. This does not change
the SHA1 of scripts since the SHA1 is computed on the body we pass to
EVAL, without the other code we add to register the function.
Close#2951.
Example of offending code:
> script debug yes
OK
> eval "local a = {1} a[1] = a\nprint(a)" 0
1) * Stopped at 1, stop reason = step over
2) -> 1 local a = {1} a[1] = a
> next
1) * Stopped at 2, stop reason = step over
2) -> 2 print(a)
> print
... server crash ...
Close#2955.
Now it lists code around the current position by default. Can list any
other part using other arguments, but a new "whole" command was added in
order to show the whole source code easily.
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.
