Merge #214

214: Add --no-clean flag r=taiki-e a=taiki-e

cargo-llvm-cov cleans some build artifacts by default to avoid false positives/false negatives due to old build artifacts.
This behavior is disabled when `--no-clean`, `--no-report`, or `--no-run` is passed, and old build artifacts are retained.
When using these flags, it is recommended to first run `cargo llvm-cov clean --workspace` to remove artifacts that may affect the coverage results.

```sh
cargo llvm-cov clean --workspace # remove artifacts that may affect the coverage results
cargo llvm-cov --no-clean
```

Closes #198 (In the long term I want to remove the need for these clean, but it is not easy.)

Co-authored-by: Taiki Endo <te316e89@gmail.com>

CHANGELOG.md

@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Add `--no-clean` flag to build without cleaning any old build artifacts. See [#214](https://github.com/taiki-e/cargo-llvm-cov/pull/214) for more.
+
 - cargo-llvm-cov no longer redirects output from stdout to stderr if unnecessary. ([#206](https://github.com/taiki-e/cargo-llvm-cov/pull/206))
 
 ## [0.4.14] - 2022-08-06

README.md

@@ -130,6 +130,9 @@ OPTIONS:
         --no-report
             Run tests, but don't generate coverage report
 
+        --no-clean
+            Build without cleaning any old build artifacts
+
         --fail-under-lines <MIN>
             Exit with a status of 1 if the total line coverage is less than MIN percent
 
@@ -358,6 +361,15 @@ cargo llvm-cov --html          # run tests and generate html report
 cargo llvm-cov --no-run --lcov # generate lcov report
 ```
 
+cargo-llvm-cov cleans some build artifacts by default to avoid false positives/false negatives due to old build artifacts.
+This behavior is disabled when `--no-clean`, `--no-report`, or `--no-run` is passed, and old build artifacts are retained.
+When using these flags, it is recommended to first run `cargo llvm-cov clean --workspace` to remove artifacts that may affect the coverage results.
+
+```sh
+cargo llvm-cov clean --workspace # remove artifacts that may affect the coverage results
+cargo llvm-cov --no-clean
+```
+
 ### Merge coverages generated under different test conditions
 
 You can merge the coverages generated under different test conditions by using `--no-report` and `--no-run`.

docs/cargo-llvm-cov-run.txt

@@ -84,6 +84,9 @@ OPTIONS:
         --no-report
             Run tests, but don't generate coverage report
 
+        --no-clean
+            Build without cleaning any old build artifacts
+
         --fail-under-lines <MIN>
             Exit with a status of 1 if the total line coverage is less than MIN percent
 

docs/cargo-llvm-cov.txt

@@ -86,6 +86,9 @@ OPTIONS:
         --no-report
             Run tests, but don't generate coverage report
 
+        --no-clean
+            Build without cleaning any old build artifacts
+
         --fail-under-lines <MIN>
             Exit with a status of 1 if the total line coverage is less than MIN percent
 

src/clean.rs

@@ -33,15 +33,16 @@ pub(crate) fn run(options: &mut Args) -> Result<()> {
     Ok(())
 }
 
-// If --no-run or --no-report is used: do not remove artifacts
+// TODO: remove need for this.
+// If --no-clean, --no-run, or --no-report is used: do not remove artifacts
 // Otherwise, remove the followings to avoid false positives/false negatives:
 // - build artifacts of crates to be measured for coverage
 // - profdata
 // - profraw
 // - doctest bins
 // - old reports
 pub(crate) fn clean_partial(cx: &Context) -> Result<()> {
-    if cx.no_run || cx.cov.no_report {
+    if cx.build.no_clean {
         return Ok(());
     }
 

src/cli.rs

@@ -179,6 +179,7 @@ impl Args {
         let mut remap_path_prefix = false;
         let mut include_ffi = false;
         let mut verbose: usize = 0;
+        let mut no_clean = false;
 
         // show-env options
         let mut export_prefix = false;
@@ -329,6 +330,7 @@ impl Args {
                 Long("remap-path-prefix") => parse_flag!(remap_path_prefix),
                 Long("include-ffi") => parse_flag!(include_ffi),
                 Short('v') | Long("verbose") => verbose += 1,
+                Long("no-clean") => parse_flag!(no_clean),
 
                 // llvm-cov options
                 Long("json") => parse_flag!(json),
@@ -435,8 +437,16 @@ impl Args {
         }
 
         // conflicts
-        if no_run && no_report {
-            conflicts("--no-run", "--no-report")?;
+        if no_report && no_run {
+            conflicts("--no-report", "--no-run")?;
+        }
+        if no_report || no_run {
+            let flag = if no_report { "--no-report" } else { "--no-run" };
+            if no_clean {
+                // --no-report/--no-run implicitly enable --no-clean.
+                conflicts(flag, "--no-clean")?;
+            }
+            no_clean = true;
         }
         if ignore_run_fail && no_fail_fast {
             // --ignore-run-fail implicitly enable --no-fail-fast.
@@ -600,6 +610,7 @@ impl Args {
                 color,
                 remap_path_prefix,
                 include_ffi,
+                no_clean,
             },
             manifest: ManifestOptions { manifest_path },
             cargo_args,
@@ -812,6 +823,10 @@ pub(crate) struct BuildOptions {
     /// must be set to Clang/LLVM compatible with the LLVM version used in rustc.
     // TODO: support specifying languages like: --include-ffi=c,  --include-ffi=c,c++
     pub(crate) include_ffi: bool,
+    /// Build without cleaning any old build artifacts.
+    ///
+    /// Note that this can cause false positives/false negatives due to old build artifacts.
+    pub(crate) no_clean: bool,
 }
 
 #[derive(Debug)]

src/context.rs

@@ -20,7 +20,6 @@ pub(crate) struct Context {
     pub(crate) cov: LlvmCovOptions,
 
     pub(crate) doctests: bool,
-    pub(crate) no_run: bool,
 
     pub(crate) workspace_members: WorkspaceMembers,
     pub(crate) build_script_re: Regex,
@@ -50,7 +49,6 @@ impl Context {
         exclude: &[String],
         exclude_from_report: &[String],
         doctests: bool,
-        no_run: bool,
         show_env: bool,
     ) -> Result<Self> {
         let ws = Workspace::new(manifest, build.target.as_deref(), doctests, show_env)?;
@@ -137,7 +135,6 @@ impl Context {
             build,
             cov,
             doctests,
-            no_run,
             workspace_members,
             build_script_re,
             current_dir: env::current_dir().unwrap(),

src/main.rs

@@ -78,16 +78,8 @@ fn try_main() -> Result<()> {
         }
 
         Subcommand::Run => {
-            let cx = &Context::new(
-                args.build(),
-                &args.manifest(),
-                args.cov(),
-                &[],
-                &[],
-                false,
-                false,
-                false,
-            )?;
+            let cx =
+                &Context::new(args.build(), &args.manifest(), args.cov(), &[], &[], false, false)?;
 
             clean::clean_partial(cx)?;
             create_dirs(cx)?;
@@ -167,7 +159,6 @@ fn context_from_args(args: &mut Args, show_env: bool) -> Result<Context> {
         &args.exclude,
         &args.exclude_from_report,
         args.doctests,
-        args.no_run,
         show_env,
     )
 }