Grcov create a sub-folder inside the same previous output folder when the output type is html

[FirelightFlagboy]

Tools version

$ cargo --version
cargo 1.68.2 (6feb7c9cf 2023-03-26)
$ grcov --version                                                                            
grcov 0.8.18

Replication steps

1. Create an example project:

   cargo new --lib

2. Generate coverage data using example tests:

   RUSTFLAGS="-C instrument-coverage -C codegen-units=1" cargo test

3. Generate coverage report in HTML:

   grcov --output-path=html/ --output-type=html --binary-path=target/debug/deps .

4. List output directory:

   $ tree html                                                                     
   html
   ├── badges
   │   ├── flat_square.svg
   │   ├── flat.svg
   │   ├── for_the_badge.svg
   │   ├── plastic.svg
   │   └── social.svg
   ├── coverage.json
   └── index.html
   
   2 directories, 7 files

5. Re-generate coverage report

   grcov --output-path=html/ --output-type=html --binary-path=target/debug/deps .

6. List output directory

   $ tree html                                                                     
   html
   ├── badges
   │   ├── flat_square.svg
   │   ├── flat.svg
   │   ├── for_the_badge.svg
   │   ├── plastic.svg
   │   └── social.svg
   ├── coverage.json
   ├── html
   │   ├── badges
   │   │   ├── flat_square.svg
   │   │   ├── flat.svg
   │   │   ├── for_the_badge.svg
   │   │   ├── plastic.svg
   │   │   └── social.svg
   │   ├── coverage.json
   │   └── index.html
   └── index.html
   
   4 directories, 14 files

   Note here the folder html inside the folder of the same name.

Expected result

I was expected grcov to not create another folder html in the output folder html and to just reuse the folder html by overwriting files that need to be.

[hartwork]

I found out that -o html/ (with slash) and -o html (without slash) behave differently: With slash will get you two layers of html, without slash will not. Not ideal, but might be good to know.

[detly]

This caught me out, and I was not using a trailing /. Thought I was losing my mind because the coverage numbers wouldn't change no matter what I did.

[qsantos]

Same here. Using a trailing slash changes nothing.

$ grcov . -s . --binary-path target/debug -t html -o ./target/debug/coverage/
$ ls ./target/debug/coverage
badges  src  tests  coverage.json  index.html
$ grcov . -s . --binary-path target/debug -t html -o ./target/debug/coverage/
$ ls ./target/debug/coverage
badges  html  src  tests  coverage.json  index.html

$ grcov . -s . --binary-path target/debug -t html -o ./target/debug/coverage
$ ls ./target/debug/coverage
badges  src  tests  coverage.json  index.html
$ grcov . -s . --binary-path target/debug -t html -o ./target/debug/coverage
$ ls ./target/debug/coverage
badges  html  src  tests  coverage.json  index.html

[hartwork]

@qsantos that path does not end in html. Try with and without trailing slash and ending in html. I have proof for grcov 0.8.18 at https://github.com/hartwork/rust-for-it/actions/runs/6906333800 for that very case.

[qsantos]

Hello @hartwork, thank for the suggestion! Unfortunately, I still get the same behavior:

$ rm -Rf target/debug/coverage
$ grcov . -s . --binary-path target/debug -t html --branch -o ./target/debug/coverage/html
$ ls ./target/debug/coverage/html
badges  src  tests  coverage.json  index.html
$ grcov . -s . --binary-path target/debug -t html --branch -o ./target/debug/coverage/html
$ ls ./target/debug/coverage/html
badges  html  src  tests  coverage.json  index.html
$ grcov --version
grcov 0.8.19

In your GitHub workflow, I only a single call to grcov with -o target/coverage/html. Since this is running in a CI, wouldn't the fact that you do not get target/coverage/html/html be explained by the fact that the directory target/coverage/html is not kept between runs?

[qsantos]

By the way, my own solution is to just mkdir -p ./target/debug/coverage/ before running grcov to always have the same behavior on consecutive local runs.

[hartwork]

@qsantos thanks for sharing these details! 👍