new command: `spack maintainers` queries package maintainers

- We don't currently make enough use of the maintainers field on
  packages, though we could use it to assign reviews.

- add a command that allows maintainers to be queried
  - can ask who is maintaining a package or packages
  - can ask what packages users are maintaining
  - can list all maintained or unmaintained packages

- add tests for the command

2 files changed, 251 insertions, 0 deletions

diff --git a/lib/spack/spack/cmd/maintainers.py b/lib/spack/spack/cmd/maintainers.py
new file mode 100644
index 0000000000..361437ece5
--- /dev/null
+++ b/lib/spack/spack/cmd/maintainers.py
@@ -0,0 +1,134 @@
+# Copyright 2013-2019 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)
+
+from __future__ import print_function
+
+import argparse
+from collections import defaultdict
+
+import llnl.util.tty as tty
+import llnl.util.tty.color as color
+from llnl.util.tty.colify import colify
+
+
+import spack.repo
+
+description = "get information about package maintainers"
+section = "developer"
+level = "long"
+
+
+def setup_parser(subparser):
+    maintained_group = subparser.add_mutually_exclusive_group()
+    maintained_group.add_argument(
+        '--maintained', action='store_true', default=False,
+        help='show names of maintained packages')
+
+    maintained_group.add_argument(
+        '--unmaintained', action='store_true', default=False,
+        help='show names of unmaintained packages')
+
+    subparser.add_argument(
+        '-a', '--all', action='store_true', default=False,
+        help='show maintainers for all packages')
+
+    subparser.add_argument(
+        '--by-user', action='store_true', default=False,
+        help='show packages for users instead of users for packages')
+
+    # options for commands that take package arguments
+    subparser.add_argument(
+        'pkg_or_user', nargs=argparse.REMAINDER,
+        help='names of packages or users to get info for')
+
+
+def packages_to_maintainers(package_names=None):
+    if not package_names:
+        package_names = spack.repo.path.all_package_names()
+
+    pkg_to_users = defaultdict(lambda: set())
+    for name in package_names:
+        cls = spack.repo.path.get_pkg_class(name)
+        for user in cls.maintainers:
+            pkg_to_users[name].add(user)
+
+    return pkg_to_users
+
+
+def maintainers_to_packages(users=None):
+    user_to_pkgs = defaultdict(lambda: [])
+    for name in spack.repo.path.all_package_names():
+        cls = spack.repo.path.get_pkg_class(name)
+        for user in cls.maintainers:
+            lower_users = [u.lower() for u in users]
+            if not users or user.lower() in lower_users:
+                user_to_pkgs[user].append(cls.name)
+
+    return user_to_pkgs
+
+
+def maintained_packages():
+    maintained = []
+    unmaintained = []
+    for name in spack.repo.path.all_package_names():
+        cls = spack.repo.path.get_pkg_class(name)
+        if cls.maintainers:
+            maintained.append(name)
+        else:
+            unmaintained.append(name)
+
+    return maintained, unmaintained
+
+
+def union_values(dictionary):
+    """Given a dictionary with values that are Collections, return their union.
+
+    Arguments:
+        dictionary (dict): dictionary whose values are all collections.
+
+    Return:
+        (set): the union of all collections in the dictionary's values.
+    """
+    sets = [set(p) for p in dictionary.values()]
+    return sorted(set.union(*sets)) if sets else set()
+
+
+def maintainers(parser, args):
+    if args.maintained or args.unmaintained:
+        maintained, unmaintained = maintained_packages()
+        pkgs = maintained if args.maintained else unmaintained
+        colify(pkgs)
+        return 0 if pkgs else 1
+
+    if args.all:
+        if args.by_user:
+            maintainers = maintainers_to_packages(args.pkg_or_user)
+            for user, packages in sorted(maintainers.items()):
+                color.cprint('@c{%s}: %s'
+                             % (user, ', '.join(sorted(packages))))
+            return 0 if maintainers else 1
+
+        else:
+            packages = packages_to_maintainers(args.pkg_or_user)
+            for pkg, maintainers in sorted(packages.items()):
+                color.cprint('@c{%s}: %s'
+                             % (pkg, ', '.join(sorted(maintainers))))
+            return 0 if packages else 1
+
+    if args.by_user:
+        if not args.pkg_or_user:
+            tty.die('spack maintainers --by-user requires a user or --all')
+
+        packages = union_values(maintainers_to_packages(args.pkg_or_user))
+        colify(packages)
+        return 0 if packages else 1
+
+    else:
+        if not args.pkg_or_user:
+            tty.die('spack maintainers requires a package or --all')
+
+        users = union_values(packages_to_maintainers(args.pkg_or_user))
+        colify(users)
+        return 0 if users else 1
diff --git a/lib/spack/spack/test/cmd/maintainers.py b/lib/spack/spack/test/cmd/maintainers.py
new file mode 100644
index 0000000000..5ddf176c39
--- /dev/null
+++ b/lib/spack/spack/test/cmd/maintainers.py
@@ -0,0 +1,117 @@
+# Copyright 2013-2019 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)
+
+from __future__ import print_function
+
+import pytest
+import re
+
+import spack.main
+import spack.repo
+
+maintainers = spack.main.SpackCommand('maintainers')
+
+
+def split(output):
+    """Split command line output into an array."""
+    output = output.strip()
+    return re.split(r'\s+', output) if output else []
+
+
+def test_maintained(mock_packages):
+    out = split(maintainers('--maintained'))
+    assert out == ['maintainers-1', 'maintainers-2']
+
+
+def test_unmaintained(mock_packages):
+    out = split(maintainers('--unmaintained'))
+    assert out == sorted(
+        set(spack.repo.all_package_names()) -
+        set(['maintainers-1', 'maintainers-2']))
+
+
+def test_all(mock_packages, capfd):
+    with capfd.disabled():
+        out = split(maintainers('--all'))
+    assert out == [
+        'maintainers-1:', 'user1,', 'user2',
+        'maintainers-2:', 'user2,', 'user3',
+    ]
+
+    with capfd.disabled():
+        out = split(maintainers('--all', 'maintainers-1'))
+    assert out == [
+        'maintainers-1:', 'user1,', 'user2',
+    ]
+
+
+def test_all_by_user(mock_packages, capfd):
+    with capfd.disabled():
+        out = split(maintainers('--all', '--by-user'))
+    assert out == [
+        'user1:', 'maintainers-1',
+        'user2:', 'maintainers-1,', 'maintainers-2',
+        'user3:', 'maintainers-2',
+    ]
+
+    with capfd.disabled():
+        out = split(maintainers('--all', '--by-user', 'user1', 'user2'))
+    assert out == [
+        'user1:', 'maintainers-1',
+        'user2:', 'maintainers-1,', 'maintainers-2',
+    ]
+
+
+def test_no_args(mock_packages):
+    with pytest.raises(spack.main.SpackCommandError):
+        maintainers()
+
+
+def test_no_args_by_user(mock_packages):
+    with pytest.raises(spack.main.SpackCommandError):
+        maintainers('--by-user')
+
+
+def test_mutex_args_fail(mock_packages):
+    with pytest.raises(SystemExit):
+        maintainers('--maintained', '--unmaintained')
+
+
+def test_maintainers_list_packages(mock_packages, capfd):
+    with capfd.disabled():
+        out = split(maintainers('maintainers-1'))
+    assert out == ['user1', 'user2']
+
+    with capfd.disabled():
+        out = split(maintainers('maintainers-1', 'maintainers-2'))
+    assert out == ['user1', 'user2', 'user3']
+
+    with capfd.disabled():
+        out = split(maintainers('maintainers-2'))
+    assert out == ['user2', 'user3']
+
+
+def test_maintainers_list_fails(mock_packages, capfd):
+    out = maintainers('a', fail_on_error=False)
+    assert not out
+    assert maintainers.returncode == 1
+
+
+def test_maintainers_list_by_user(mock_packages, capfd):
+    with capfd.disabled():
+        out = split(maintainers('--by-user', 'user1'))
+    assert out == ['maintainers-1']
+
+    with capfd.disabled():
+        out = split(maintainers('--by-user', 'user1', 'user2'))
+    assert out == ['maintainers-1', 'maintainers-2']
+
+    with capfd.disabled():
+        out = split(maintainers('--by-user', 'user2'))
+    assert out == ['maintainers-1', 'maintainers-2']
+
+    with capfd.disabled():
+        out = split(maintainers('--by-user', 'user3'))
+    assert out == ['maintainers-2']