Line coverage showing incorrect values when `tracing::instrument` attribute is used
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Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 45/100
- Issue type
- Bug
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- rust
- Domain
- testing-qa
Research direction
Reproduce the report using the Docker, cargo, llvm-tools-preview, and grcov commands provided, comparing HTML coverage with tracing::instrument enabled and disabled. No source file or test is named; completion means explaining or correcting the discrepancy so the untested line is excluded and the reported coverage matches the expected 94.74%.
Written by the indexing model from the issue text.
Description
I'm using tracing::instrument attribute to collect telemetry data in some of my functions. However, this is generating inconsistent line coverage values. For instance, see the following two screenshots (the first one with tracing::instrument enabled and the second with it disabled).
Coverage with tracing::instrument uncommented:
Coverage with tracing::instrument commented out:
94.74% of line coverage should be the correct value since line 8 is not being tested. However, this line coverage is not detected when the tracing::instrument attribute is enabled, ultimately presenting an incorrect 100% line coverage value.
So is this indeed an issue? And is there something I can do to solve this? I'd like to continue using tracing::instrument, but get the correct coverage results.
Here it's the commands I'm using to generate the grcov results:
IMAGE=rust:1.65.0; docker run -v "$PWD":/proofs -w /proofs --privileged -it "$IMAGE"
export RUSTFLAGS="-Cinstrument-coverage"
export LLVM_PROFILE_FILE="proofs-%p-%m.profraw"
cargo install grcov@0.8.13
rustup component add llvm-tools-preview
cargo build
cargo test
grcov . --binary-path ./target/debug/ -s . -t html --branch --ignore-not-existing -o ./code_coverage/
My Cargo.toml:
[package]
name = "test-coverage"
version = "0.1.0"
edition = "2021"
[dependencies]
tracing = { version = "0.1.36", features = ["attributes"] }
- Dominant language
- Rust
- Stars
- 1.4k
- Forks
- 170
- Avg merge
- 3d 10h
- Merged PRs (30d)
- 4
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