From d084f7a0777b2479ee76dc7cd1b5f2a83be9471a Mon Sep 17 00:00:00 2001
From: Thibault Saunier <tsaunier@igalia.com>
Date: Thu, 2 May 2024 07:56:35 -0400
Subject: [PATCH] Workaround copying file returning EAGAIN on ZFS on mac OS

Falling back to hard_link when that happens, retrying can lead to very
long wait before copying works (up to 4secs in my tests) while
hard_linking works straight away.

Looks related to https://github.com/openzfsonosx/zfs/issues/809

Closes #13838
---
 crates/cargo-util/Cargo.toml   |  4 ++--
 crates/cargo-util/src/paths.rs | 18 +++++++++++++++++-
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/crates/cargo-util/Cargo.toml b/crates/cargo-util/Cargo.toml
index 28877eedaf76..43a6b0969d58 100644
--- a/crates/cargo-util/Cargo.toml
+++ b/crates/cargo-util/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "cargo-util"
-version = "0.2.12"
-rust-version = "1.77"  # MSRV:1
+version = "0.2.13"
+rust-version = "1.77"                                     # MSRV:1
 edition.workspace = true
 license.workspace = true
 homepage.workspace = true
diff --git a/crates/cargo-util/src/paths.rs b/crates/cargo-util/src/paths.rs
index 1172b002885d..f890390b0e08 100644
--- a/crates/cargo-util/src/paths.rs
+++ b/crates/cargo-util/src/paths.rs
@@ -585,7 +585,23 @@ fn _link_or_copy(src: &Path, dst: &Path) -> Result<()> {
             // Note that: fs::copy on macos is using CopyOnWrite (syscall fclonefileat) which should be
             // as fast as hardlinking.
             // See https://github.com/rust-lang/cargo/issues/10060 for the details
-            fs::copy(src, dst).map(|_| ())
+            fs::copy(src, dst).map_or_else(
+                |e| {
+                    if e.raw_os_error()
+                        .map_or(false, |os_err| os_err == 35 /* libc::EAGAIN */)
+                    {
+                        tracing::info!("copy failed {e:?}. falling back to fs::hard_link");
+
+                        // Working around an issue copying too fast with zfs (probably related to
+                        // https://github.com/openzfsonosx/zfs/issues/809)
+                        // See https://github.com/rust-lang/cargo/issues/13838
+                        fs::hard_link(src, dst)
+                    } else {
+                        Err(e)
+                    }
+                },
+                |_| Ok(()),
+            )
         } else {
             fs::hard_link(src, dst)
         }