chore: add mypy

bin/lint

@@ -16,3 +16,4 @@ python -m black --check *.py warehouse/ tests/
 python -m isort --check *.py warehouse/ tests/
 python -m doc8 --allow-long-titles README.rst CONTRIBUTING.rst docs/ --ignore-path docs/_build/
 python -m curlylint ./warehouse/templates
+python -m mypy -p warehouse

pyproject.toml

@@ -8,6 +8,57 @@ lines_between_types = 1
 combine_as_imports = true
 known_first_party = ['warehouse', 'tests']
 
+[tool.mypy]
+python_version = "3.9"
+namespace_packages = true
+warn_unused_configs = true
+plugins = ["mypy_zope:plugin"]
+exclude = ["warehouse/locale/.*", "warehouse/migrations/versions.*"]
+
+[[tool.mypy.overrides]]
+# These modules do not yet have types available.
+module = [
+    "automat.*",
+    "babel.*",
+    "bpython.*",
+    "celery.app.backends.*",
+    "celery.backends.redis.*",
+    "citext.*",
+    "disposable_email_domains.*",
+    "elasticsearch_dsl.*", # https://github.com/elastic/elasticsearch-dsl-py/issues/1533
+    "google.cloud.*",
+    "IPython.*",
+    "mistune.*",
+    "msgpack.*",
+    "paginate.*",
+    "paginate_sqlalchemy.*",
+    "passlib.*",
+    "premailer.*",
+    "pymacaroons.*", # https://github.com/ecordell/pymacaroons/issues/41
+    "pyramid.*", # https://github.com/Pylons/pyramid/issues/2638
+    "pyramid_jinja2.*",
+    "pyramid_mailer.*",
+    "pyramid_multiauth.*",
+    "pyramid_retry.*",
+    "pyramid_rpc.*",
+    "pyqrcode.*",
+    "readme_renderer.*", # https://github.com/pypa/readme_renderer/issues/166
+    "requests_aws4auth.*",
+    "rfc3986.*",
+    "stdlib_list.*",
+    "sqlalchemy.*", # https://docs.sqlalchemy.org/en/14/orm/extensions/mypy.html
+    "sqlalchemy_utils.*",
+    "transaction.*",
+    "trove_classifiers.*",
+    "venusian.*",
+    "whitenoise.*",
+    "wtforms.*", # https://github.com/wtforms/wtforms/issues/618
+    "yara.*",
+    "zxcvbn.*", # https://github.com/dwolfhub/zxcvbn-python/issues/56
+    "zope.sqlalchemy.*",
+]
+ignore_missing_imports = true
+
 [tool.pytest.ini_options]
 norecursedirs = ['build', 'dist', 'node_modules', '*.egg-info', '.state requirements']
 markers = [

requirements/lint.in

@@ -4,3 +4,17 @@ curlylint
 pep8-naming
 black==22.1.0
 isort>=5
+mypy
+celery-types
+mypy-zope
+types-boto3
+types-certifi
+types-first
+types-html5lib
+types-itsdangerous
+types-psycopg2
+types-python-slugify
+types-pytz
+types-redis
+types-requests
+types-setuptools

requirements/lint.txt

@@ -33,6 +33,18 @@ black==22.1.0 \
     --hash=sha256:f5660feab44c2e3cb24b2419b998846cbb01c23c7fe645fee45087efa3da2d61 \
     --hash=sha256:fdb8754b453fb15fad3f72cd9cad3e16776f0964d67cf30ebcbf10327a3777a3
     # via -r requirements/lint.in
+boto3-stubs==1.21.13 \
+    --hash=sha256:4d490b296754e3bef8350b22be02d54590bfc1967e24e2e1e9d256f2ffbd5b82 \
+    --hash=sha256:5ede068ad7c8e426af0938ebcf5f417610a1745a387f9ceca1398c9da7956f08
+    # via types-boto3
+botocore-stubs==1.24.13 \
+    --hash=sha256:d172f4dde2df15c90bb6926801fe8cc6fad4d91d094faf35c34f69b8203d2b57 \
+    --hash=sha256:eddcb423f18817cad8f4fcba4db8f24ebb21f16a5c0e28e09771099edb47fcce
+    # via boto3-stubs
+celery-types==0.11.0 \
+    --hash=sha256:88a95c5513d62145583235ad03050352ed4b8294003d0a5a012c959c09ec68d3 \
+    --hash=sha256:95134cb0899c7cd1116edc8d8017e1fe156697247e9657e6cdf56ed362de56cb
+    # via -r requirements/lint.in
 click==8.0.4 \
     --hash=sha256:6a7a62563bbfabfda3a38f3023a1db4a35978c0abd76f6c9605ecd6554d6d9b1 \
     --hash=sha256:8458d7b1287c5fb128c90e23381cf99dcde74beaf6c7ff6384ce84d6fe090adb
@@ -72,10 +84,40 @@ mccabe==0.6.1 \
     --hash=sha256:ab8a6258860da4b6677da4bd2fe5dc2c659cff31b3ee4f7f5d64e79735b80d42 \
     --hash=sha256:dd8d182285a0fe56bace7f45b5e7d1a6ebcbf524e8f3bd87eb0f125271b8831f
     # via flake8
+mypy==0.931 \
+    --hash=sha256:0038b21890867793581e4cb0d810829f5fd4441aa75796b53033af3aa30430ce \
+    --hash=sha256:1171f2e0859cfff2d366da2c7092b06130f232c636a3f7301e3feb8b41f6377d \
+    --hash=sha256:1b06268df7eb53a8feea99cbfff77a6e2b205e70bf31743e786678ef87ee8069 \
+    --hash=sha256:1b65714dc296a7991000b6ee59a35b3f550e0073411ac9d3202f6516621ba66c \
+    --hash=sha256:1bf752559797c897cdd2c65f7b60c2b6969ffe458417b8d947b8340cc9cec08d \
+    --hash=sha256:300717a07ad09525401a508ef5d105e6b56646f7942eb92715a1c8d610149714 \
+    --hash=sha256:3c5b42d0815e15518b1f0990cff7a705805961613e701db60387e6fb663fe78a \
+    --hash=sha256:4365c60266b95a3f216a3047f1d8e3f895da6c7402e9e1ddfab96393122cc58d \
+    --hash=sha256:50c7346a46dc76a4ed88f3277d4959de8a2bd0a0fa47fa87a4cde36fe247ac05 \
+    --hash=sha256:5b56154f8c09427bae082b32275a21f500b24d93c88d69a5e82f3978018a0266 \
+    --hash=sha256:74f7eccbfd436abe9c352ad9fb65872cc0f1f0a868e9d9c44db0893440f0c697 \
+    --hash=sha256:7b3f6f557ba4afc7f2ce6d3215d5db279bcf120b3cfd0add20a5d4f4abdae5bc \
+    --hash=sha256:8c11003aaeaf7cc2d0f1bc101c1cc9454ec4cc9cb825aef3cafff8a5fdf4c799 \
+    --hash=sha256:8ca7f8c4b1584d63c9a0f827c37ba7a47226c19a23a753d52e5b5eddb201afcd \
+    --hash=sha256:c89702cac5b302f0c5d33b172d2b55b5df2bede3344a2fbed99ff96bddb2cf00 \
+    --hash=sha256:d8f1ff62f7a879c9fe5917b3f9eb93a79b78aad47b533911b853a757223f72e7 \
+    --hash=sha256:d9d2b84b2007cea426e327d2483238f040c49405a6bf4074f605f0156c91a47a \
+    --hash=sha256:e839191b8da5b4e5d805f940537efcaa13ea5dd98418f06dc585d2891d228cf0 \
+    --hash=sha256:f9fe20d0872b26c4bba1c1be02c5340de1019530302cf2dcc85c7f9fc3252ae0 \
+    --hash=sha256:ff3bf387c14c805ab1388185dd22d6b210824e164d4bb324b195ff34e322d166
+    # via
+    #   -r requirements/lint.in
+    #   mypy-zope
 mypy-extensions==0.4.3 \
     --hash=sha256:090fedd75945a69ae91ce1303b5824f428daf5a028d2f6ab8a299250a846f15d \
     --hash=sha256:2d82818f5bb3e369420cb3c4060a7970edba416647068eb4c5343488a6c604a8
-    # via black
+    # via
+    #   black
+    #   mypy
+mypy-zope==0.3.5 \
+    --hash=sha256:3bd0cc9a3e5933b02931af4b214ba32a4f4ff98adb30c979ce733857db91a18b \
+    --hash=sha256:489e7da1c2af887f2cfe3496995fc247f296512b495b57817edddda9d22308f3
+    # via -r requirements/lint.in
 parsy==1.1.0 \
     --hash=sha256:25bd5cea2954950ebbfdf71f8bdaf7fd45a5df5325fd36a1064be2204d9d4c94 \
     --hash=sha256:36173ba01a5372c7a1b32352cc73a279a49198f52252adf1c8c1ed41d1f94e8d
@@ -124,8 +166,131 @@ toml==0.10.2 \
 tomli==2.0.1 \
     --hash=sha256:939de3e7a6161af0c887ef91b7d41a53e7c5a1ca976325f429cb46ea9bc30ecc \
     --hash=sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f
-    # via black
+    # via
+    #   black
+    #   mypy
+types-boto3==1.0.1 \
+    --hash=sha256:392d5fdbb40ea0fb20f5116897e96b5e6c5b4a784e8c75aec1f5e12f2ebe3438 \
+    --hash=sha256:4eb8aad23d4287d2f5b30a36e742f108beab8e0d55eb73817fdce405b8eef95e
+    # via -r requirements/lint.in
+types-certifi==2021.10.8.1 \
+    --hash=sha256:2290008f32e6ac7c69e779d04fa1bc4c6bb4c7200aa3b3b072ad5475a8968aa5 \
+    --hash=sha256:546cd3ca4466855959fbc8868fd7139a50eb55a2d1fae497e13b60af439597a3
+    # via -r requirements/lint.in
+types-first==2.0.2 \
+    --hash=sha256:129155be97b4a65a86a2b4cbc6f2d1de5b40d2c5d370289779fd6dd0293b69f6 \
+    --hash=sha256:444b4eaba3342f3d360f9f49eb4a175538da212e31ed1f26ee9b54c23f5fa0de
+    # via -r requirements/lint.in
+types-html5lib==1.1.5 \
+    --hash=sha256:15435ea831ee0fef4cca1382998d51c1e81447ccd38664baab4fb50249695372 \
+    --hash=sha256:6e190a4e466e3f96f2128fd936a10b1159a57142d01628b0c515f4fc48d2e094
+    # via -r requirements/lint.in
+types-itsdangerous==1.1.6 \
+    --hash=sha256:21c6966c10e353a5d35d36c82aaa2c5598d3bc32ddc8e0591276da5ad2e3c638 \
+    --hash=sha256:aef2535c2fa0527dcce244ece0792b20ec02ee46533800735275f82a45a0244d
+    # via -r requirements/lint.in
+types-psycopg2==2.9.7 \
+    --hash=sha256:90e9393c04ac29af7f000578629020b488f6435abb283d928c1bd8eabb846e14 \
+    --hash=sha256:cc876db5aa77773deb0abe2e5b088842b91163261294b36caaf7e1087e7e8cd2
+    # via -r requirements/lint.in
+types-python-slugify==5.0.3 \
+    --hash=sha256:76169f4a6d40896fea76fb45a25c50ac7ba2ca03eee759ecac322a05fe4dd21c \
+    --hash=sha256:a5761d3c55e949f8ace0694eb5be81210087084bb78df495de14ee5eaad6ac54
+    # via -r requirements/lint.in
+types-pytz==2021.3.5 \
+    --hash=sha256:8831f689379ac9e2a62668157381379ed74b3702980e08e71f8673c179c4e3c7 \
+    --hash=sha256:fef8de238ee95135952229a2a23bfb87bd63d5a6c8598106a46cfcf48f069ea8
+    # via -r requirements/lint.in
+types-redis==4.1.17 \
+    --hash=sha256:5c8707423c60e70ba6ff9a5f01baacbb6c871e44f6a2bd562790cee9edd5b5b1 \
+    --hash=sha256:7e98c567f0e279b47b0a0ddee8c0180a086e4a5f1b95e6890b40b2a84dc97fb6
+    # via -r requirements/lint.in
+types-requests==2.27.11 \
+    --hash=sha256:506279bad570c7b4b19ac1f22e50146538befbe0c133b2cea66a9b04a533a859 \
+    --hash=sha256:6a7ed24b21780af4a5b5e24c310b2cd885fb612df5fd95584d03d87e5f2a195a
+    # via -r requirements/lint.in
+types-setuptools==57.4.9 \
+    --hash=sha256:536ef74744f8e1e4be4fc719887f886e74e4cf3c792b4a06984320be4df450b5 \
+    --hash=sha256:948dc6863373750e2cd0b223a84f1fb608414cde5e55cf38ea657b93aeb411d2
+    # via -r requirements/lint.in
+types-urllib3==1.26.10 \
+    --hash=sha256:a26898f530e6c3f43f25b907f2b884486868ffd56a9faa94cbf9b3eb6e165d6a \
+    --hash=sha256:d755278d5ecd7a7a6479a190e54230f241f1a99c19b81518b756b19dc69e518c
+    # via types-requests
 typing-extensions==4.1.1 \
     --hash=sha256:1a9462dcc3347a79b1f1c0271fbe79e844580bb598bafa1ed208b94da3cdcd42 \
     --hash=sha256:21c85e0fe4b9a155d0799430b0ad741cdce7e359660ccbd8b530613e8df88ce2
-    # via black
+    # via
+    #   black
+    #   mypy
+zope-event==4.5.0 \
+    --hash=sha256:2666401939cdaa5f4e0c08cf7f20c9b21423b95e88f4675b1443973bdb080c42 \
+    --hash=sha256:5e76517f5b9b119acf37ca8819781db6c16ea433f7e2062c4afc2b6fbedb1330
+    # via zope-schema
+zope-interface==5.4.0 \
+    --hash=sha256:08f9636e99a9d5410181ba0729e0408d3d8748026ea938f3b970a0249daa8192 \
+    --hash=sha256:0b465ae0962d49c68aa9733ba92a001b2a0933c317780435f00be7ecb959c702 \
+    --hash=sha256:0cba8477e300d64a11a9789ed40ee8932b59f9ee05f85276dbb4b59acee5dd09 \
+    --hash=sha256:0cee5187b60ed26d56eb2960136288ce91bcf61e2a9405660d271d1f122a69a4 \
+    --hash=sha256:0ea1d73b7c9dcbc5080bb8aaffb776f1c68e807767069b9ccdd06f27a161914a \
+    --hash=sha256:0f91b5b948686659a8e28b728ff5e74b1be6bf40cb04704453617e5f1e945ef3 \
+    --hash=sha256:15e7d1f7a6ee16572e21e3576d2012b2778cbacf75eb4b7400be37455f5ca8bf \
+    --hash=sha256:17776ecd3a1fdd2b2cd5373e5ef8b307162f581c693575ec62e7c5399d80794c \
+    --hash=sha256:194d0bcb1374ac3e1e023961610dc8f2c78a0f5f634d0c737691e215569e640d \
+    --hash=sha256:1c0e316c9add0db48a5b703833881351444398b04111188069a26a61cfb4df78 \
+    --hash=sha256:205e40ccde0f37496904572035deea747390a8b7dc65146d30b96e2dd1359a83 \
+    --hash=sha256:273f158fabc5ea33cbc936da0ab3d4ba80ede5351babc4f577d768e057651531 \
+    --hash=sha256:2876246527c91e101184f63ccd1d716ec9c46519cc5f3d5375a3351c46467c46 \
+    --hash=sha256:2c98384b254b37ce50eddd55db8d381a5c53b4c10ee66e1e7fe749824f894021 \
+    --hash=sha256:2e5a26f16503be6c826abca904e45f1a44ff275fdb7e9d1b75c10671c26f8b94 \
+    --hash=sha256:334701327f37c47fa628fc8b8d28c7d7730ce7daaf4bda1efb741679c2b087fc \
+    --hash=sha256:3748fac0d0f6a304e674955ab1365d515993b3a0a865e16a11ec9d86fb307f63 \
+    --hash=sha256:3c02411a3b62668200910090a0dff17c0b25aaa36145082a5a6adf08fa281e54 \
+    --hash=sha256:3dd4952748521205697bc2802e4afac5ed4b02909bb799ba1fe239f77fd4e117 \
+    --hash=sha256:3f24df7124c323fceb53ff6168da70dbfbae1442b4f3da439cd441681f54fe25 \
+    --hash=sha256:469e2407e0fe9880ac690a3666f03eb4c3c444411a5a5fddfdabc5d184a79f05 \
+    --hash=sha256:4de4bc9b6d35c5af65b454d3e9bc98c50eb3960d5a3762c9438df57427134b8e \
+    --hash=sha256:5208ebd5152e040640518a77827bdfcc73773a15a33d6644015b763b9c9febc1 \
+    --hash=sha256:52de7fc6c21b419078008f697fd4103dbc763288b1406b4562554bd47514c004 \
+    --hash=sha256:5bb3489b4558e49ad2c5118137cfeaf59434f9737fa9c5deefc72d22c23822e2 \
+    --hash=sha256:5dba5f530fec3f0988d83b78cc591b58c0b6eb8431a85edd1569a0539a8a5a0e \
+    --hash=sha256:5dd9ca406499444f4c8299f803d4a14edf7890ecc595c8b1c7115c2342cadc5f \
+    --hash=sha256:5f931a1c21dfa7a9c573ec1f50a31135ccce84e32507c54e1ea404894c5eb96f \
+    --hash=sha256:63b82bb63de7c821428d513607e84c6d97d58afd1fe2eb645030bdc185440120 \
+    --hash=sha256:66c0061c91b3b9cf542131148ef7ecbecb2690d48d1612ec386de9d36766058f \
+    --hash=sha256:6f0c02cbb9691b7c91d5009108f975f8ffeab5dff8f26d62e21c493060eff2a1 \
+    --hash=sha256:71aace0c42d53abe6fc7f726c5d3b60d90f3c5c055a447950ad6ea9cec2e37d9 \
+    --hash=sha256:7d97a4306898b05404a0dcdc32d9709b7d8832c0c542b861d9a826301719794e \
+    --hash=sha256:7df1e1c05304f26faa49fa752a8c690126cf98b40b91d54e6e9cc3b7d6ffe8b7 \
+    --hash=sha256:8270252effc60b9642b423189a2fe90eb6b59e87cbee54549db3f5562ff8d1b8 \
+    --hash=sha256:867a5ad16892bf20e6c4ea2aab1971f45645ff3102ad29bd84c86027fa99997b \
+    --hash=sha256:877473e675fdcc113c138813a5dd440da0769a2d81f4d86614e5d62b69497155 \
+    --hash=sha256:8892f89999ffd992208754851e5a052f6b5db70a1e3f7d54b17c5211e37a98c7 \
+    --hash=sha256:9a9845c4c6bb56e508651f005c4aeb0404e518c6f000d5a1123ab077ab769f5c \
+    --hash=sha256:a1e6e96217a0f72e2b8629e271e1b280c6fa3fe6e59fa8f6701bec14e3354325 \
+    --hash=sha256:a8156e6a7f5e2a0ff0c5b21d6bcb45145efece1909efcbbbf48c56f8da68221d \
+    --hash=sha256:a9506a7e80bcf6eacfff7f804c0ad5350c8c95b9010e4356a4b36f5322f09abb \
+    --hash=sha256:af310ec8335016b5e52cae60cda4a4f2a60a788cbb949a4fbea13d441aa5a09e \
+    --hash=sha256:b0297b1e05fd128d26cc2460c810d42e205d16d76799526dfa8c8ccd50e74959 \
+    --hash=sha256:bf68f4b2b6683e52bec69273562df15af352e5ed25d1b6641e7efddc5951d1a7 \
+    --hash=sha256:d0c1bc2fa9a7285719e5678584f6b92572a5b639d0e471bb8d4b650a1a910920 \
+    --hash=sha256:d4d9d6c1a455d4babd320203b918ccc7fcbefe308615c521062bc2ba1aa4d26e \
+    --hash=sha256:db1fa631737dab9fa0b37f3979d8d2631e348c3b4e8325d6873c2541d0ae5a48 \
+    --hash=sha256:dd93ea5c0c7f3e25335ab7d22a507b1dc43976e1345508f845efc573d3d779d8 \
+    --hash=sha256:f44e517131a98f7a76696a7b21b164bcb85291cee106a23beccce454e1f433a4 \
+    --hash=sha256:f7ee479e96f7ee350db1cf24afa5685a5899e2b34992fb99e1f7c1b0b758d263
+    # via
+    #   mypy-zope
+    #   zope-schema
+zope-schema==6.2.0 \
+    --hash=sha256:03150d8670549590b45109e06b7b964f4e751fa9cb5297ec4985c3bc38641b07 \
+    --hash=sha256:2201aef8ad75ee5a881284d7a6acd384661d6dca7bde5e80a22839a77124595b
+    # via mypy-zope
+
+# The following packages are considered to be unsafe in a requirements file:
+setuptools==60.9.3 \
+    --hash=sha256:2347b2b432c891a863acadca2da9ac101eae6169b1d3dfee2ec605ecd50dbfe5 \
+    --hash=sha256:e4f30b9f84e5ab3decf945113119649fec09c1fc3507c6ebffec75646c56e62b
+    # via
+    #   zope-interface
+    #   zope-schema

warehouse/accounts/models.py

@@ -135,7 +135,7 @@ def email(self):
         primary_email = self.primary_email
         return primary_email.email if primary_email else None
 
-    @email.expression
+    @email.expression  # type: ignore
     def email(self):
         return (
             select([Email.email])

warehouse/cli/__init__.py

@@ -43,5 +43,5 @@ def warehouse(ctx):
 
 # We want to automatically import all of the warehouse.cli.* modules so that
 # any commands registered in any of them will be discovered.
-for _, name, _ in pkgutil.walk_packages(__path__, prefix=__name__ + "."):
+for _, name, _ in pkgutil.walk_packages(__path__, prefix=__name__ + "."):  # type: ignore # noqa
     importlib.import_module(name)

warehouse/csrf.py

@@ -40,7 +40,7 @@ def wrapped(context, request):
     return wrapped
 
 
-require_method_view.options = {"require_methods"}
+require_method_view.options = {"require_methods"}  # type: ignore
 
 
 def includeme(config):

warehouse/db.py

@@ -24,7 +24,7 @@
 from sqlalchemy import event, inspect
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.exc import IntegrityError, OperationalError
-from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.ext.declarative import declarative_base  # type: ignore
 from sqlalchemy.orm import sessionmaker
 
 from warehouse.metrics import IMetricsService
@@ -97,7 +97,7 @@ def __repr__(self):
 
 
 # Base class for models using declarative syntax
-ModelBase = declarative_base(cls=ModelBase, metadata=metadata)
+ModelBase = declarative_base(cls=ModelBase, metadata=metadata)  # type: ignore
 
 
 class Model(ModelBase):

warehouse/email/ses/models.py

@@ -251,7 +251,7 @@ class EmailMessage(db.Model):
         backref="email",
         cascade="all, delete-orphan",
         lazy=False,
-        order_by=lambda: Event.created,
+        order_by=lambda: Event.created,  # type: ignore
     )
 
 

warehouse/i18n/__init__.py

@@ -170,7 +170,7 @@ def wrapped(context, request):
         return wrapped
 
 
-translated_view.options = {"has_translations"}
+translated_view.options = {"has_translations"}  # type: ignore
 
 
 def includeme(config):

warehouse/legacy/api/xmlrpc/cache/derivers.py

@@ -43,7 +43,7 @@ def wrapper_view(context, request):
     return view
 
 
-cached_return_view.options = [
+cached_return_view.options = [  # type: ignore
     "xmlrpc_cache",
     "xmlrpc_cache_tag",
     "xmlrpc_cache_expires",

warehouse/legacy/api/xmlrpc/cache/interfaces.py

@@ -24,7 +24,7 @@ def create_service(context, request):
         created for.
         """
 
-    def fetch(self, func, args, kwargs, key, tag, expire):
+    def fetch(func, args, kwargs, key, tag, expire):
         """
         Gets cached function return value from the cache or calls func with the
         supplied args and kwargs, stashing it in the cache. Cache is drawn from
@@ -33,13 +33,13 @@ def fetch(self, func, args, kwargs, key, tag, expire):
         expiration.
         """
 
-    def purge(self, tag):
+    def purge(tag):
         """
         Issues a purge, clearing all cached objects associated with the tag
         from the cache.
         """
 
-    def purge_tags(self, tags):
+    def purge_tags(tags):
         """
         Issues a purge, clearing all cached objects associated with each tag
         in the iterable tags.