Make stage use concrete specs from environment (#22320)

* Make stage use concrete specs from environment

Same as in https://github.com/spack/spack/pull/21642, the idea is that
we want to easily stage a package that fails to build in a complex
environment. Instead of making the user create a spec by hand (basically
transforming all the rules in the environment manifest into a spec,
defying the purpose of the environment...), use the provided spec as a
filter for the already concretized specs. This also speeds up things,
cause we don't have to reconcretize.

lib/spack/spack/cmd/stage.py

@@ -41,8 +41,14 @@ def stage(parser, args):
     if args.deprecated:
         spack.config.set('config:deprecated', True, scope='command_line')
 
-    specs = spack.cmd.parse_specs(args.specs, concretize=True)
+    specs = spack.cmd.parse_specs(args.specs, concretize=False)
+
+    # prevent multiple specs from extracting in the same folder
+    if len(specs) > 1 and args.path:
+        tty.die("`--path` requires a single spec, but multiple were provided")
+
     for spec in specs:
+        spec = spack.cmd.matching_spec_from_env(spec)
         package = spack.repo.get(spec)
         if args.path:
             package.path = args.path

lib/spack/spack/test/cmd/stage.py

@@ -0,0 +1,114 @@
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+import pytest
+from spack.main import SpackCommand
+import spack.environment as ev
+import spack.repo
+from spack.version import Version
+
+
+stage = SpackCommand('stage')
+env = SpackCommand('env')
+
+pytestmark = pytest.mark.usefixtures('install_mockery', 'mock_packages')
+
+
+def test_stage_spec(monkeypatch):
+    """Verify that staging specs works."""
+
+    expected = set(['trivial-install-test-package', 'mpileaks'])
+
+    def fake_stage(pkg, mirror_only=False):
+        expected.remove(pkg.name)
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    stage('trivial-install-test-package', 'mpileaks')
+
+    assert len(expected) == 0
+
+
+def test_stage_path(monkeypatch):
+    """Verify that --path only works with single specs."""
+
+    def fake_stage(pkg, mirror_only=False):
+        assert pkg.path == 'x'
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    stage('--path=x', 'trivial-install-test-package')
+
+
+def test_stage_path_errors_multiple_specs(monkeypatch):
+    """Verify that --path only works with single specs."""
+
+    def fake_stage(pkg, mirror_only=False):
+        pass
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    with pytest.raises(spack.main.SpackCommandError):
+        stage('--path=x', 'trivial-install-test-package', 'mpileaks')
+
+
+def test_stage_with_env_outside_env(mutable_mock_env_path, monkeypatch):
+    """Verify that stage concretizes specs not in environment instead of erroring."""
+
+    def fake_stage(pkg, mirror_only=False):
+        assert pkg.name == 'trivial-install-test-package'
+        assert pkg.path is None
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    e = ev.create('test')
+    e.add('mpileaks')
+    e.concretize()
+
+    with e:
+        stage('trivial-install-test-package')
+
+
+def test_stage_with_env_inside_env(mutable_mock_env_path, monkeypatch):
+    """Verify that stage filters specs in environment instead of reconcretizing."""
+
+    def fake_stage(pkg, mirror_only=False):
+        assert pkg.name == 'mpileaks'
+        assert pkg.version == Version('100.100')
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    e = ev.create('test')
+    e.add('mpileaks@100.100')
+    e.concretize()
+
+    with e:
+        stage('mpileaks')
+
+
+def test_stage_full_env(mutable_mock_env_path, monkeypatch):
+    """Verify that stage filters specs in environment."""
+
+    e = ev.create('test')
+    e.add('mpileaks@100.100')
+    e.concretize()
+
+    # list all the package names that should be staged
+    expected = set()
+    for spec in e.specs_by_hash.values():
+        for dep in spec.traverse():
+            expected.add(dep.name)
+
+    # pop the package name from the list instead of actually staging
+    def fake_stage(pkg, mirror_only=False):
+        expected.remove(pkg.name)
+
+    monkeypatch.setattr(spack.package.PackageBase, 'do_stage', fake_stage)
+
+    with e:
+        stage()
+
+    # assert that all were staged
+    assert len(expected) == 0