chore(bottlecap): cross-platform test and code cleanups (#1211)

## Overview

Portable test and code cleanups in bottlecap. No behavior change on
Linux.

- `.gitattributes`: force LF for `*.sh` / `*.bash`. Shell scripts now
check out with LF on every platform, so a CRLF-prone checkout (e.g.
Windows) still executes cleanly inside Linux Docker containers.
- `bottlecap/src/tags/lambda/tags.rs`, the three
`tags::lambda::tags::tests::test_resolve_*` tests:
- Switch from a hard-coded `/tmp/...` path to `std::env::temp_dir()`.
Removes a bootstrap race between tests that were implicitly sharing a
filesystem side effect through the same path.
- Render paths with `to_string_lossy()` so a non-UTF-8 temp dir does not
panic the test.
  - `test_resolve_runtime` now cleans up the file it created.
- `bottlecap/src/metrics/enhanced/statfs.rs`:
- `statfs_info` is `fn` on both targets. It's an internal helper; `pub`
was only present on the non-Windows branch.
- The existing `#[cfg(target_os = "windows")]` stub now uses
`io::Error::other(..)` (per `clippy::io_other_error`) and prefixes its
unused `path` with `_`.

> Origin: these commits were split out of #1193 after review feedback,
so the portable cleanups can land independently of the broader
Windows-build discussion.

## Testing

- `cargo check` on Linux: clean.
- `cargo test --lib tags::lambda::tags::`: 8 passed, 0 failed.

> *"Turns out 'make the tests not race on Windows' is also 'make the
tests not race on Linux'."*, Claude 🤖

Author: lucaspimentel

.gitattributes

@@ -1 +1,6 @@
 /LICENSE-3rdparty.csv linguist-generated=true
+
+# Set line endings to LF, even on Windows. Otherwise, execution within Docker fails.
+# See https://help.github.com/articles/dealing-with-line-endings/
+*.sh text eol=lf
+*.bash text eol=lf

bottlecap/src/metrics/enhanced/statfs.rs

@@ -9,7 +9,7 @@ use std::path::Path;
 #[allow(clippy::cast_lossless)]
 /// Returns the block size, total number of blocks, and number of blocks available for the specified directory path.
 ///
-pub fn statfs_info(path: &str) -> Result<(f64, f64, f64), io::Error> {
+fn statfs_info(path: &str) -> Result<(f64, f64, f64), io::Error> {
     let stat = statfs(Path::new(path)).map_err(io::Error::other)?;
     Ok((
         stat.block_size() as f64,
@@ -19,11 +19,8 @@ pub fn statfs_info(path: &str) -> Result<(f64, f64, f64), io::Error> {
 }
 
 #[cfg(target_os = "windows")]
-fn statfs_info(path: &str) -> Result<(f64, f64, f64), io::Error> {
-    Err(io::Error::new(
-        io::ErrorKind::Other,
-        "Cannot get tmp data on Windows",
-    ))
+fn statfs_info(_path: &str) -> Result<(f64, f64, f64), io::Error> {
+    Err(io::Error::other("Cannot get tmp data on Windows"))
 }
 
 pub fn get_tmp_max() -> Result<f64, io::Error> {

bottlecap/src/tags/lambda/tags.rs

@@ -294,7 +294,6 @@ mod tests {
     use std::collections::HashMap;
     use std::fs::File;
     use std::io::Write;
-    use std::path::Path;
 
     #[test]
     fn test_new_from_config() {
@@ -368,8 +367,8 @@ mod tests {
 
     #[test]
     fn test_resolve_runtime() {
-        let proc_id_folder = Path::new("/tmp/test-bottlecap/proc_root/123");
-        fs::create_dir_all(proc_id_folder).unwrap();
+        let proc_id_folder = std::env::temp_dir().join("test-bottlecap/proc_root/123");
+        fs::create_dir_all(&proc_id_folder).unwrap();
         let path = proc_id_folder.join("environ");
         let content = "\0NAME =\"AmazonLinux\"\0V=\"2\0AWS_EXECUTION_ENV=\"AWS_Lambda_java123\"\0somethingelse=\"abd\0\"";
 
@@ -378,32 +377,33 @@ mod tests {
 
         let runtime =
             resolve_runtime_from_proc(proc_id_folder.parent().unwrap().to_str().unwrap(), "");
-        fs::remove_file(path).unwrap();
+        fs::remove_file(&path).unwrap();
+        fs::remove_dir_all(std::env::temp_dir().join("test-bottlecap")).unwrap();
         assert_eq!(runtime, "java123");
     }
 
     #[test]
     fn test_resolve_provided_al2() {
-        let path = "/tmp/test-os-release1";
+        let path = std::env::temp_dir().join("test-os-release1");
         let content = "NAME =\"Amazon Linux\"\nVERSION=\"2\nPRETTY_NAME=\"Amazon Linux 2\"";
-        let mut file = File::create(path).unwrap();
+        let mut file = File::create(&path).unwrap();
         file.write_all(content.as_bytes()).unwrap();
 
-        let runtime = resolve_runtime_from_proc("", path);
-        fs::remove_file(path).unwrap();
+        let runtime = resolve_runtime_from_proc("", &path.to_string_lossy());
+        fs::remove_file(&path).unwrap();
         assert_eq!(runtime, "provided.al2");
     }
 
     #[test]
     fn test_resolve_provided_al2023() {
-        let path = "/tmp/test-os-release2";
+        let path = std::env::temp_dir().join("test-os-release2");
         let content =
             "NAME=\"Amazon Linux\"\nVERSION=\"2\nPRETTY_NAME=\"Amazon Linux 2023.4.20240429\"";
-        let mut file = File::create(path).unwrap();
+        let mut file = File::create(&path).unwrap();
         file.write_all(content.as_bytes()).unwrap();
 
-        let runtime = resolve_runtime_from_proc("", path);
-        fs::remove_file(path).unwrap();
+        let runtime = resolve_runtime_from_proc("", &path.to_string_lossy());
+        fs::remove_file(&path).unwrap();
         assert_eq!(runtime, "provided.al2023");
     }