Lines counted as missed when calling methods on next line.

[ZoteTheMighty]

This issue occurs when using syntax like the following:

local greeting = ("hello, %s")
	:format("world")

Running luacov on a file containing only this code reports coverage as:

*0 local greeting = ("hello, %s")
 1 	:format("world")

If it helps, I'm running this with Lua 5.1.5. This syntax can be pretty clean, so it'd be really nice if luacov understood it!

[hishamhm]

Hi! Thanks for reporting. Unfortunately, we are limited to the precision of the information that the debug library of the running Lua implementation provides us. It does not report the second line. Lua and LuaJIT versions all provide different data (LuaJIT, in particular, provides unreliable data when the JIT compiler is on.) It would not be technically impossible to detect this particular construct you described, but I'm not sure we'd be able to catch all cases. Given that the first line of a call expression runs then its following lines must run if it wasn't aborted during a subexpression, so if the following line executed then it would be fair to assume that the entire expression executed. However, to do that reliably it would require a full parse of the Lua source code, which luacov doesn't currently do, and we would be effectively extrapolating information from the data we're given by Lua.

[ZoteTheMighty]

Okay, that makes sense. I had a feeling it might be infeasible. Thanks for the explanation!

[utmhikari]

that's what lua state machine features and we have to fix similar problems as far as possible
holy craaaaap