[major] number of lines covered not accurate?

[timotheecour]

• [ ] why are there 27 lines considered as executed? I only see 4 lines in blue (in another test file, the number of blue lines was matching the number of lines considered as executed)
• [ ] why is line 12 in blue? inconsistent: this means if you have N 1-line funcitons, you get N+1 executed lines?

Note: this was after running:

git clone https://github.com/timotheecour/vitanim
cd vitanim/drange
coco

• [ ] it shows 5 functions but I only see 3; note: this may explain why (clicking on functions); but is quite confusing:

[timotheecour]

other example where I don't understand line count:

• import typetraits should probably not be counted as a runtime line (not executed at runtime)
• why is ret &= a.front in red but not a.popFront ?
• why is r:R in a type section in blue ? (since not executed at runtime)
• why is ## filter in blue (it's a comment)

[samuelroy]

it shows 5 functions but I only see 3;

The Nim compiler creates 2 more proc which are yourfile_yourfileInit and yourfile_yourfileDatInit. here's an example with Coco:

This one is harmless because it seems it's always used and as such covered.

[timotheecour]

should we have an option to discount it from line/function/branch coverage stats? otherwise it inflates the numbers

[samuelroy]

I'm still digging this and it seems actually GCOV/LCOV might not be the perfect solution for code coverage.

Simple example, 1 test file imports 1 function from another Nim file like so:

## Minimal nim file used in tests for checking compilation and coverage
import ../coco

echo get_cache_folder("foo.nim", "bar", 42)

After compilation, we have a C file containing only the required function, not the whole Coco library:

#line 18 "/Users/sam/Code/nim-coverage/coco.nim"
N_LIB_PRIVATE N_NIMCALL(NimStringDesc*, get_cache_folder_2hKxOP9bo6u9buKgLZs3GK2Q)(NimStringDesc* filename, NimStringDesc* nimcache, NI increment) {
    NimStringDesc* result;  NimStringDesc* fmtRes;  nimfr_("get_cache_folder", "coco.nim"); result = (NimStringDesc*)0;
#line 19 "/Users/sam/Code/nim-coverage/coco.nim"
    nimln_(19, "coco.nim");
#line 19 "/Users/sam/Code/nim-coverage/coco.nim"

#line 19 "/Users/sam/Code/nim-coverage/coco.nim"
    fmtRes = rawNewString(((NI) 67));
# and so on....

And the LCOV.info contains only the following:

SF:/Users/sam/Code/nim-coverage/coco.nim
FN:18,get_cache_folder_2hKxOP9bo6u9buKgLZs3GK2Q
FN:20,coco_cocoInit000
FN:26,coco_cocoDatInit000
FNDA:1,get_cache_folder_2hKxOP9bo6u9buKgLZs3GK2Q
FNDA:1,coco_cocoInit000
FNDA:1,coco_cocoDatInit000
FNF:3
FNH:3
DA:19,4
DA:22,2
DA:24,1
DA:27,2
DA:260,6
DA:268,1
LF:6
LH:6
end_of_record

Resulting in a wrong coverage because there's only one function instead of everything.

So either I need to parse Nim files by hand to consolidate the results or try to find X (compiler flags?) to generate C files more in sync with the Nim sources.

[timotheecour]

parse Nim files by hand

whatever the right way is, this isn't it ;-)

[timotheecour]

• random completely untested idea off the top of my head:

for each file bar.nim you want coverage on, generate a coverage_bar.nim with contents:

include bar.nim

[timotheecour]

So either I need to parse Nim files by hand to consolidate the results or try to find X (compiler flags?) to generate C files more in sync with the Nim sources.

with https://github.com/nim-lang/Nim/pull/9560 at list you could list public symbols; but may not be exactly what's needed here

[ratiotile]

Is the nim compiler removing dead code? --deadCodeElim:off

[samuelroy]

Is the nim compiler removing dead code? --deadCodeElim:off

Thanks for your suggestion. I tried the flag but it didn't help. Unfortunately I think this project is out of my reach as I'm totally new to Nim.