sandbox/_sandboxbwrap.py: Fix fuse import issuechandan/fix-fuse-check

This will fix an issue where BuildStream currently throws an exception
when running on Linux without fuse.

Fixes #1081.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/buildstream/sandbox/_sandboxbwrap.py b/src/buildstream/sandbox/_sandboxbwrap.py
index 17f999ac0..1155793c6 100644
--- a/src/buildstream/sandbox/_sandboxbwrap.py
+++ b/src/buildstream/sandbox/_sandboxbwrap.py
@@ -36,7 +36,6 @@ import psutil
 
 from .._exceptions import SandboxError
 from .. import utils, _signals
-from ._mount import MountMap
 from . import Sandbox, SandboxFlags
 from .. import _site
 
@@ -147,6 +146,12 @@ class SandboxBwrap(Sandbox):
                                "'{}'".format(command[0]),
                                reason='missing-command')
 
+        # NOTE: MountMap transitively imports `_fuse/fuse.py` which raises an
+        # EnvironmentError when fuse is not found. Since this module is
+        # expected to be imported even in absence of fuse, MountMap is imported
+        # here, and not at the top of the module.
+        from ._mount import MountMap
+
         # Create the mount map, this will tell us where
         # each mount point needs to be mounted from and to
         mount_map = MountMap(self, flags & SandboxFlags.ROOT_READ_ONLY)