Environments: unify the spec objects on first concretization (#29948)

Currently environments are indexed by build hashes. When looking into this bug I noticed there is a disconnect between environments that are concretized in memory for the first time and environments that are read from a `spack.lock`. The issue is that specs read from a `spack.lock` don't have a full hash, since they are indexed by a build hash which is strictly coarser. They are also marked "final" as they are read from a file, so we can't compute additional hashes. 

This bugfix PR makes "first concretization" equivalent to re-reading the specs from a corresponding `spack.lock`, and doing so unveiled a few tests were we were making wrong assumptions and relying on the fact that a `spack.lock` file was not there already.

* Add unit test
* Modify mpich to trigger jobs in pipelines
* Fix two failing unit tests
* Fix another full_hash vs. build_hash mismatch in tests

lib/spack/spack/environment/environment.py

@@ -1271,11 +1271,33 @@ def _concretize_separately(self, tests=False):
 
         finish = time.time()
         tty.msg('Environment concretized in %.2f seconds.' % (finish - start))
-        results = []
+        by_hash = {}
         for abstract, concrete in zip(root_specs, concretized_root_specs):
             self._add_concrete_spec(abstract, concrete)
-            results.append((abstract, concrete))
+            by_hash[concrete.build_hash()] = concrete
 
+        # Unify the specs objects, so we get correct references to all parents
+        self._read_lockfile_dict(self._to_lockfile_dict())
+
+        # Re-attach information on test dependencies
+        if tests:
+            # This is slow, but the information on test dependency is lost
+            # after unification or when reading from a lockfile.
+            for h in self.specs_by_hash:
+                current_spec, computed_spec = self.specs_by_hash[h], by_hash[h]
+                for node in computed_spec.traverse():
+                    test_deps = node.dependencies(deptype='test')
+                    for test_dependency in test_deps:
+                        if test_dependency in current_spec[node.name]:
+                            continue
+                        current_spec[node.name].add_dependency_edge(
+                            test_dependency.copy(), deptype='test'
+                        )
+
+        results = [
+            (abstract, self.specs_by_hash[h]) for abstract, h in
+            zip(self.concretized_user_specs, self.concretized_order)
+        ]
         return results
 
     def concretize_and_add(self, user_spec, concrete_spec=None, tests=False):

lib/spack/spack/test/ci.py

@@ -579,3 +579,15 @@ def test_get_spec_filter_list(mutable_mock_env_path, config, mutable_mock_repo):
                                        'libelf'])
 
     assert affected_pkg_names == expected_affected_pkg_names
+
+
+@pytest.mark.regression('29947')
+def test_affected_specs_on_first_concretization(mutable_mock_env_path, config):
+    e = ev.create('first_concretization')
+    e.add('hdf5~mpi~szip')
+    e.add('hdf5~mpi+szip')
+    e.concretize()
+
+    affected_specs = spack.ci.get_spec_filter_list(e, ['zlib'])
+    hdf5_specs = [s for s in affected_specs if s.name == 'hdf5']
+    assert len(hdf5_specs) == 2

lib/spack/spack/test/cmd/ci.py

@@ -1731,12 +1731,12 @@ def test_ci_reproduce(tmpdir, mutable_mock_env_path,
             job_spec_yaml_path = os.path.join(
                 working_dir.strpath, 'archivefiles.yaml')
             with open(job_spec_yaml_path, 'w') as fd:
-                fd.write(job_spec.to_yaml(hash=ht.full_hash))
+                fd.write(job_spec.to_yaml(hash=ht.build_hash))
 
             root_spec_yaml_path = os.path.join(
                 working_dir.strpath, 'root.yaml')
             with open(root_spec_yaml_path, 'w') as fd:
-                fd.write(root_spec.to_yaml(hash=ht.full_hash))
+                fd.write(root_spec.to_yaml(hash=ht.build_hash))
 
             artifacts_root = os.path.join(working_dir.strpath, 'scratch_dir')
             pipeline_path = os.path.join(artifacts_root, 'pipeline.yml')

lib/spack/spack/test/cmd/install.py

@@ -851,7 +851,7 @@ def test_install_no_add_in_env(tmpdir, mock_fetch, install_mockery,
         # but not added as a root
         mpi_spec_yaml_path = tmpdir.join('{0}.yaml'.format(mpi_spec.name))
         with open(mpi_spec_yaml_path.strpath, 'w') as fd:
-            fd.write(mpi_spec.to_yaml(hash=ht.full_hash))
+            fd.write(mpi_spec.to_yaml(hash=ht.build_hash))
 
         install('--no-add', '-f', mpi_spec_yaml_path.strpath)
         assert(mpi_spec not in e.roots())