From b59a46eef09f8a4a4e11ab604b26db6c7607d750 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Thu, 13 Aug 2020 15:27:15 +0200
Subject: [PATCH] loader: work around Windows symlink limitation

Currently there will be a problem if the TinyGo installation directory
is not the same filesystem as the cache directory (usually the C drive)
and Developer Mode is disabled. Therefore, let's add another fallback
for when both conditions are true, falling back to copying the file
instead of symlinking/hardlinking it.
---
 loader/goroot.go | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/loader/goroot.go b/loader/goroot.go
index d9cf6ad7ec..621b92cb36 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -8,6 +8,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"math/rand"
 	"os"
@@ -228,10 +229,27 @@ func symlink(oldname, newname string) error {
 				return symlinkErr
 			}
 		} else {
-			// Make a hard link.
+			// Try making a hard link.
 			err := os.Link(oldname, newname)
 			if err != nil {
-				return symlinkErr
+				// Making a hardlink failed. Try copying the file as a last
+				// fallback.
+				inf, err := os.Open(oldname)
+				if err != nil {
+					return err
+				}
+				defer inf.Close()
+				outf, err := os.Create(newname)
+				if err != nil {
+					return err
+				}
+				defer outf.Close()
+				_, err = io.Copy(outf, inf)
+				if err != nil {
+					os.Remove(newname)
+					return err
+				}
+				// File was copied.
 			}
 		}
 		return nil // success