Commit f8dc6fc416

@@ -762,7 +762,11 @@ pub const Manifest = struct {
 
     fn downgradeToSharedLock(self: *Manifest) !void {
         if (!self.have_exclusive_lock) return;
-        if (std.process.can_spawn or !builtin.single_threaded) { // Some targets (WASI) do not support flock
+
+        // WASI does not currently support flock, so we bypass it here.
+        // TODO: If/when flock is supported on WASI, this check should be removed.
+        //       See https://github.com/WebAssembly/wasi-filesystem/issues/2
+        if (builtin.os.tag != .wasi or std.process.can_spawn or !builtin.single_threaded) {
             const manifest_file = self.manifest_file.?;
             try manifest_file.downgradeLock();
         }
@@ -771,7 +775,11 @@ pub const Manifest = struct {
 
     fn upgradeToExclusiveLock(self: *Manifest) !void {
         if (self.have_exclusive_lock) return;
-        if (std.process.can_spawn or !builtin.single_threaded) { // Some targets (WASI) do not support flock
+
+        // WASI does not currently support flock, so we bypass it here.
+        // TODO: If/when flock is supported on WASI, this check should be removed.
+        //       See https://github.com/WebAssembly/wasi-filesystem/issues/2
+        if (builtin.os.tag != .wasi or std.process.can_spawn or !builtin.single_threaded) {
             const manifest_file = self.manifest_file.?;
             // Here we intentionally have a period where the lock is released, in case there are
             // other processes holding a shared lock.