Add tests for spack external dependencies, plus fixes for issues found by those tests.

lib/spack/spack/concretize.py

@@ -85,8 +85,8 @@ def _valid_virtuals_and_externals(self, spec):
             provider_cmp = partial(spack.pkgsort.provider_compare, spec_w_preferred_providers.name, spec.name)
             packages = sorted(providers, cmp=provider_cmp)
         else:
-            if not spec_externals(spec) or spec.external:
-                return None
+            if spec.external:
+                return False
             packages = [spec]
 
         # For each candidate package, if it has externals add those to the candidates
@@ -129,7 +129,7 @@ def concretize_virtual_and_external(self, spec):
                 #Try a looser ABI matching
                 candidate = next((c for c in candidates if spack.abi.compatible(c[0], other_spec, loose=True)), None)
         if not candidate:
-            #Pick the first choice
+            #No ABI matches. Pick the top choice based on the orignal preferences.
             candidate = candidates[0]
         external = candidate[1]
         candidate_spec = candidate[0]
@@ -144,10 +144,11 @@ def concretize_virtual_and_external(self, spec):
         if not spec.external and external:
             spec.external = external
             changed = True
+
         #If we're external then trim the dependencies
         if external and spec.dependencies:
             changed = True
-            spec.depencencies = DependencyMap()
+            spec.dependencies = DependencyMap()
         
         return changed
         

lib/spack/spack/spec.py

@@ -1022,7 +1022,7 @@ def _normalize_helper(self, visited, spec_deps, provider_index):
 
         # if we descend into a virtual spec, there's nothing more
         # to normalize.  Concretize will finish resolving it later.
-        if self.virtual:
+        if self.virtual or self.external:
             return False
 
         # Combine constraints from package deps with constraints from

lib/spack/spack/test/concretize.py

@@ -192,3 +192,31 @@ def test_compiler_inheritance(self):
         # TODO: not exactly the syntax I would like.
         self.assertTrue(spec['libdwarf'].compiler.satisfies('clang'))
         self.assertTrue(spec['libelf'].compiler.satisfies('clang'))
+
+
+    def test_external_package(self):
+        spec = Spec('externaltool')
+        spec.concretize()
+
+        self.assertEqual(spec['externaltool'].external, '/path/to/external_tool')
+        self.assertFalse('externalprereq' in spec)
+        self.assertTrue(spec['externaltool'].compiler.satisfies('gcc'))
+
+
+    def test_nobuild_package(self):
+        got_error = False
+        spec = Spec('externaltool%clang')
+        try:
+            spec.concretize()
+        except spack.concretize.NoBuildError:
+            got_error = True
+        self.assertTrue(got_error)
+
+
+    def test_external_and_virtual(self):
+        spec = Spec('externaltest')
+        spec.concretize()
+        self.assertTrue(spec['externaltool'].external, '/path/to/external_tool')
+        self.assertTrue(spec['stuff'].external, '/path/to/external_virtual_gcc')
+        self.assertTrue(spec['externaltool'].compiler.satisfies('gcc'))
+        self.assertTrue(spec['stuff'].compiler.satisfies('gcc'))