spack fetch: don't fetch externals. (#6124)

Fixes #6123

spack fetch shouldn't attempt to fetch external deps when invoked
with --dependencies.

1 files changed, 8 insertions, 1 deletions

diff --git a/lib/spack/spack/cmd/fetch.py b/lib/spack/spack/cmd/fetch.py
index 7394903bfb..48ffcd39f4 100644
--- a/lib/spack/spack/cmd/fetch.py
+++ b/lib/spack/spack/cmd/fetch.py
@@ -40,7 +40,7 @@ def setup_parser(subparser):
         help="do not check packages against checksum")
     subparser.add_argument(
         '-m', '--missing', action='store_true',
-        help="also fetch all missing dependencies")
+        help="fetch only missing (not yet installed) dependencies")
     subparser.add_argument(
         '-D', '--dependencies', action='store_true',
         help="also fetch all dependencies")
@@ -61,8 +61,15 @@ def fetch(parser, args):
         if args.missing or args.dependencies:
             for s in spec.traverse():
                 package = spack.repo.get(s)
+
+                # Skip already-installed packages with --missing
                 if args.missing and package.installed:
                     continue
+
+                # Do not attempt to fetch externals (they're local)
+                if package.spec.external:
+                    continue
+
                 package.do_fetch()
 
         package = spack.repo.get(spec)