From dc4c31eb50a0abec7be55daf08491f979a72fc85 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Fri, 9 Apr 2021 14:15:58 -0700
Subject: [PATCH] Build using relative path in repo if Windows lost symlink

---
 serde_derive_internals/build.rs | 12 ++++++++++++
 serde_derive_internals/lib.rs   |  3 ++-
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 serde_derive_internals/build.rs

diff --git a/serde_derive_internals/build.rs b/serde_derive_internals/build.rs
new file mode 100644
index 00000000..b2a2d04a
--- /dev/null
+++ b/serde_derive_internals/build.rs
@@ -0,0 +1,12 @@
+use std::path::Path;
+
+fn main() {
+    // Sometimes on Windows the git checkout does not correctly wire up the
+    // symlink from serde_derive_internals/src to serde_derive/src/internals.
+    // When this happens we'll just build based on relative paths within the git
+    // repo.
+    let mod_behind_symlink = Path::new("src/mod.rs");
+    if !mod_behind_symlink.exists() {
+        println!("cargo:rustc-cfg=serde_build_from_git");
+    }
+}
diff --git a/serde_derive_internals/lib.rs b/serde_derive_internals/lib.rs
index 2e36229b..5c5abdff 100644
--- a/serde_derive_internals/lib.rs
+++ b/serde_derive_internals/lib.rs
@@ -40,7 +40,8 @@ extern crate syn;
 extern crate proc_macro2;
 extern crate quote;
 
-#[path = "src/mod.rs"]
+#[cfg_attr(serde_build_from_git, path = "../serde_derive/src/internals/mod.rs")]
+#[cfg_attr(not(serde_build_from_git), path = "src/mod.rs")]
 mod internals;
 
 pub use internals::*;