From af13c831771e6b49063222079a743c843d753f77 Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Mon, 4 Dec 2023 18:59:35 -0500
Subject: [PATCH] Overwrite individual files when reflinking (#556)

Similar to #516, but for individual files.

## Test Plan

Ran:

```sh
cargo run -p puffin-cli -- pip-uninstall plaid-python
mkdir -p /Users/crmarsh/workspace/puffin/.venv/lib/python3.10/site-packages/tests
echo "x=1" > /Users/crmarsh/workspace/puffin/.venv/lib/python3.10/site-packages/tests/__init__.py
cargo run -p puffin-cli -- pip-sync requirements.txt --no-cache --verbose
```
---
 crates/install-wheel-rs/src/linker.rs | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/crates/install-wheel-rs/src/linker.rs b/crates/install-wheel-rs/src/linker.rs
index 7d68a2aed..fed7189f4 100644
--- a/crates/install-wheel-rs/src/linker.rs
+++ b/crates/install-wheel-rs/src/linker.rs
@@ -256,7 +256,7 @@ fn clone_wheel_files(
     // On macOS, directly can be recursively copied with a single `clonefile` call.
     // So we only need to iterate over the top-level of the directory, and copy each file or
     // subdirectory unless the subdirectory exists already in which case we'll need to recursively
-    // merge its contents with the existing direcotry.
+    // merge its contents with the existing directory.
     for entry in fs::read_dir(wheel.as_ref())? {
         let entry = entry?;
         let from = entry.path();
@@ -276,17 +276,22 @@ fn clone_recursive(from: &Path, to: &Path) -> Result<(), Error> {
     debug!("Cloning {} to {}", from.display(), to.display());
     let reflink = reflink_copy::reflink(from, to);
 
-    // If copying fails and the directory exists already, it must be merged recursively
-    if from.is_dir()
-        && reflink
-            .as_ref()
-            .is_err_and(|err| matches!(err.kind(), std::io::ErrorKind::AlreadyExists))
+    if reflink
+        .as_ref()
+        .is_err_and(|err| matches!(err.kind(), std::io::ErrorKind::AlreadyExists))
     {
-        for entry in fs::read_dir(from)? {
-            let entry = entry?;
-            let child_from = entry.path();
-            let child_to = to.join(child_from.strip_prefix(from).unwrap());
-            clone_recursive(child_from.as_path(), child_to.as_path())?;
+        // If copying fails and the directory exists already, it must be merged recursively.
+        if from.is_dir() {
+            for entry in fs::read_dir(from)? {
+                let entry = entry?;
+                let child_from = entry.path();
+                let child_to = to.join(child_from.strip_prefix(from).unwrap());
+                clone_recursive(child_from.as_path(), child_to.as_path())?;
+            }
+        } else {
+            // If file already exists, remove it and overwrite.
+            fs::remove_file(to)?;
+            reflink_copy::reflink(from, to)?;
         }
     } else {
         // Other errors should be tracked