Remove __pycache__ directories when uninstalling (#397)

According to the [packaging
documentation](https://packaging.python.org/en/latest/specifications/binary-distribution-format/#binary-distribution-format),
"uninstallers should be smart enough to remove .pyc even if it is not
mentioned in RECORD". Previously, we weren't handling this case, so if
you installed via Puffin, then imported a file (to trigger bytecode
compilation), then uninstalled, we'd leave spare `__pycache__`
directories around.

Closes https://github.com/astral-sh/puffin/issues/395.

crates/install-wheel-rs/src/uninstall.rs

@@ -64,6 +64,19 @@ pub fn uninstall_wheel(dist_info: &Path) -> Result<Uninstall, Error> {
                 break;
             }
 
+            // If the directory contains a `__pycache__` directory, always remove it. `__pycache__`
+            // may or may not be listed in the RECORD, but installers are expected to be smart
+            // enough to remove it either way.
+            let pycache = path.join("__pycache__");
+            match fs::remove_dir_all(&pycache) {
+                Ok(()) => {
+                    debug!("Removed directory: {}", pycache.display());
+                    dir_count += 1;
+                }
+                Err(err) if err.kind() == std::io::ErrorKind::NotFound => {}
+                Err(err) => return Err(err.into()),
+            }
+
             // Try to read from the directory. If it doesn't exist, assume we deleted it in a
             // previous iteration.
             let mut read_dir = match fs::read_dir(path) {

crates/puffin-cli/tests/pip_uninstall.rs

@@ -1,10 +1,11 @@
 use std::process::Command;
 
 use anyhow::Result;
+use assert_cmd::prelude::*;
 use assert_fs::prelude::*;
 use insta_cmd::{assert_cmd_snapshot, get_cargo_bin};
 
-use common::BIN_NAME;
+use common::{BIN_NAME, INSTA_FILTERS};
 
 mod common;
 
@@ -125,3 +126,62 @@ dependencies = ["flask==1.0.x"]
 
     Ok(())
 }
+
+#[test]
+fn uninstall() -> Result<()> {
+    let temp_dir = assert_fs::TempDir::new()?;
+    let cache_dir = assert_fs::TempDir::new()?;
+    let venv = temp_dir.child(".venv");
+
+    Command::new(get_cargo_bin(BIN_NAME))
+        .arg("venv")
+        .arg(venv.as_os_str())
+        .arg("--cache-dir")
+        .arg(cache_dir.path())
+        .current_dir(&temp_dir)
+        .assert()
+        .success();
+    venv.assert(predicates::path::is_dir());
+
+    let requirements_txt = temp_dir.child("requirements.txt");
+    requirements_txt.touch()?;
+    requirements_txt.write_str("MarkupSafe==2.1.3")?;
+
+    Command::new(get_cargo_bin(BIN_NAME))
+        .arg("pip-sync")
+        .arg("requirements.txt")
+        .arg("--cache-dir")
+        .arg(cache_dir.path())
+        .env("VIRTUAL_ENV", venv.as_os_str())
+        .current_dir(&temp_dir)
+        .assert()
+        .success();
+
+    Command::new(venv.join("bin").join("python"))
+        .arg("-c")
+        .arg("import markupsafe")
+        .current_dir(&temp_dir)
+        .assert()
+        .success();
+
+    insta::with_settings!({
+        filters => INSTA_FILTERS.to_vec()
+    }, {
+        assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+            .arg("pip-uninstall")
+            .arg("MarkupSafe")
+            .arg("--cache-dir")
+            .arg(cache_dir.path())
+            .env("VIRTUAL_ENV", venv.as_os_str())
+            .current_dir(&temp_dir));
+    });
+
+    Command::new(venv.join("bin").join("python"))
+        .arg("-c")
+        .arg("import markupsafe")
+        .current_dir(&temp_dir)
+        .assert()
+        .failure();
+
+    Ok(())
+}

crates/puffin-cli/tests/snapshots/pip_uninstall__uninstall.snap

@@ -0,0 +1,20 @@
+---
+source: crates/puffin-cli/tests/pip_uninstall.rs
+info:
+  program: puffin
+  args:
+    - pip-uninstall
+    - MarkupSafe
+    - "--cache-dir"
+    - /var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp2hOiz7
+  env:
+    VIRTUAL_ENV: /var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp9AcnyS/.venv
+---
+success: true
+exit_code: 0
+----- stdout -----
+
+----- stderr -----
+Uninstalled 1 package in [TIME]
+ - markupsafe==2.1.3
+