project: fix detection of a previous .west/ at an intermediate level

Fix detection of some existing (and very unlikely) .west/ "pollution" at
an intermediate level, for details see first comment at
#935

This pollution is very unlikely because it's pretty difficult to have
the manifest clone more than one level down before #774 / #854 - so it's
difficult to have "intermediate" levels.

Signed-off-by: Marc Herbert <Marc.Herbert@gmail.com>

Author: marc-hb

src/west/app/project.py

@@ -417,6 +417,16 @@ def bootstrap(self, args) -> Path:
 
         manifest_abspath = topdir / manifest_path
 
+        # We already looked for old .west/ pollution earlier but only at the highest
+        # topdir/.west level because we didn't know the manifest_path yet. Now that we know
+        # "manifest_path", look again for any existing, clashing .west/ located at a lower
+        # level somewhere between the new topdir and the new manifest_path. This check will be
+        # especially useful once the new --topdir feature is available, see
+        # https://github.com/zephyrproject-rtos/west/issues/774
+        already = util.west_topdir(manifest_abspath, fall_back=False)
+        if not topdir.samefile(already):
+            self.die_already(already)
+
         # Some filesystems like NTFS can't rename files in use.
         # See west issue #558. Will ReFS address this?
         ren_delay = args.rename_delay