From cffef31906456909d304e3af96fcec4656e370d6 Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 27 Dec 2020 17:17:47 +0100
Subject: [PATCH 01/11] Add maximum of workers to config

---
 docs/docs/configuration.md        |  7 +++++++
 poetry/console/commands/config.py |  6 ++++++
 poetry/installation/executor.py   | 17 ++++++++---------
 poetry/utils/helpers.py           | 13 +++++++++++++
 4 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/docs/docs/configuration.md b/docs/docs/configuration.md
index 72310886ca7..caf24416a1f 100644
--- a/docs/docs/configuration.md
+++ b/docs/docs/configuration.md
@@ -112,6 +112,13 @@ Defaults to `true`.
         This configuration will be ignored, and parallel execution disabled when running
         Python 2.7 under Windows.
 
+### `installer.max-workers`: int
+
+Set the maximum number of workers while using the parallel installer. Defaults to `number_of_cores + 4`.
+
+!!!note:
+        This configuration will be ignored when `installer.parallel` is set to false.
+
 ### `virtualenvs.create`: boolean
 
 Create a new virtual environment if one doesn't already exist.
diff --git a/poetry/console/commands/config.py b/poetry/console/commands/config.py
index 310524d4ee2..9a71e3552b4 100644
--- a/poetry/console/commands/config.py
+++ b/poetry/console/commands/config.py
@@ -46,6 +46,7 @@ def unique_config_values(self):
         from poetry.config.config import boolean_normalizer
         from poetry.config.config import boolean_validator
         from poetry.locations import CACHE_DIR
+        from poetry.utils.helpers import get_default_max_workers
 
         unique_config_values = {
             "cache-dir": (
@@ -71,6 +72,11 @@ def unique_config_values(self):
                 False,
             ),
             "installer.parallel": (boolean_validator, boolean_normalizer, True,),
+            "installer.max-workers": (
+                lambda val: int(val) > 0,
+                lambda val: int(val),
+                get_default_max_workers(),
+            ),
         }
 
         return unique_config_values
diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index 5523ed2813f..188de6371a3 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -16,6 +16,7 @@
 from poetry.io.null_io import NullIO
 from poetry.utils._compat import decode
 from poetry.utils.env import EnvCommandError
+from poetry.utils.helpers import get_default_max_workers
 from poetry.utils.helpers import safe_rmtree
 
 from .authenticator import Authenticator
@@ -28,7 +29,7 @@
 
 
 class Executor(object):
-    def __init__(self, env, pool, config, io, parallel=None):
+    def __init__(self, env, pool, config, io, parallel=None, max_workers=None):
         self._env = env
         self._io = io
         self._dry_run = False
@@ -42,14 +43,12 @@ def __init__(self, env, pool, config, io, parallel=None):
             parallel = config.get("installer.parallel", True)
 
         if parallel:
-            # This should be directly handled by ThreadPoolExecutor
-            # however, on some systems the number of CPUs cannot be determined
-            # (it raises a NotImplementedError), so, in this case, we assume
-            # that the system only has one CPU.
-            try:
-                self._max_workers = os.cpu_count() + 4
-            except NotImplementedError:
-                self._max_workers = 5
+            self._max_workers = get_default_max_workers()
+
+            if max_workers is None:
+                max_workers = config.get("installer.max-workers", self._max_workers)
+
+            self._max_workers = min(max_workers, self._max_workers)
         else:
             self._max_workers = 1
 
diff --git a/poetry/utils/helpers.py b/poetry/utils/helpers.py
index 909ec3c1438..55ed6bf3567 100644
--- a/poetry/utils/helpers.py
+++ b/poetry/utils/helpers.py
@@ -133,3 +133,16 @@ def is_dir_writable(path, create=False):  # type: (Path, bool) -> bool
         return False
     else:
         return True
+
+
+def get_default_max_workers():
+    # This should be directly handled by ThreadPoolExecutor
+    # however, on some systems the number of CPUs cannot be determined
+    # (it raises a NotImplementedError), so, in this case, we assume
+    # that the system only has one CPU.
+    try:
+        default_max_workers = os.cpu_count() + 4
+    except NotImplementedError:
+        default_max_workers = 5
+
+    return default_max_workers

From 7bc6a22b5148a47ba1934b92177b07f2a003ce6e Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 27 Dec 2020 17:39:05 +0100
Subject: [PATCH 02/11] Trigger build

---
 poetry/installation/executor.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index 188de6371a3..2368dc33fdb 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -43,6 +43,7 @@ def __init__(self, env, pool, config, io, parallel=None, max_workers=None):
             parallel = config.get("installer.parallel", True)
 
         if parallel:
+            # Trigger build
             self._max_workers = get_default_max_workers()
 
             if max_workers is None:

From a48fd789dfd3c3dff273eb170076f12460ab944f Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 27 Dec 2020 17:45:31 +0100
Subject: [PATCH 03/11] Revert Trigger build

---
 poetry/installation/executor.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index 2368dc33fdb..188de6371a3 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -43,7 +43,6 @@ def __init__(self, env, pool, config, io, parallel=None, max_workers=None):
             parallel = config.get("installer.parallel", True)
 
         if parallel:
-            # Trigger build
             self._max_workers = get_default_max_workers()
 
             if max_workers is None:

From 5b16a4108de0ba9dece6536a216395f08f949fdd Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Mon, 28 Dec 2020 11:42:54 +0100
Subject: [PATCH 04/11] Add test for config

---
 tests/config/test_config.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index f3b13f23003..7727795ecfe 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -19,11 +19,15 @@ def test_config_get_processes_depended_on_values(config, config_cache_dir):
     [
         ("installer.parallel", "true", True),
         ("installer.parallel", "false", False),
+        ("installer.max-workers", "4", "4"),
+        ("installer.max-workers", "2", "2"),
         ("virtualenvs.create", "true", True),
         ("virtualenvs.create", "false", False),
     ],
 )
 def test_config_get_from_environment_variable(config, environ, name, env_value, value):
-    env_var = "POETRY_{}".format("_".join(k.upper() for k in name.split(".")))
+    env_var = "POETRY_{}".format(
+        "_".join(k.upper().replace("-", "_") for k in name.split("."))
+    )
     os.environ[env_var] = env_value
     assert config.get(name) is value

From 8c10e9c592dea29eebeea20b9cf3552c3c36e787 Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 14 Nov 2021 14:11:15 +0100
Subject: [PATCH 05/11] Address max workers logic

---
 poetry/console/commands/config.py |  4 ++--
 poetry/installation/executor.py   | 12 ++++--------
 poetry/utils/helpers.py           |  6 ++++--
 3 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/poetry/console/commands/config.py b/poetry/console/commands/config.py
index 5558b2924f1..799fd1a218e 100644
--- a/poetry/console/commands/config.py
+++ b/poetry/console/commands/config.py
@@ -53,7 +53,7 @@ def unique_config_values(self) -> Dict[str, Tuple[Any, Any, Any]]:
         from poetry.config.config import boolean_normalizer
         from poetry.config.config import boolean_validator
         from poetry.locations import CACHE_DIR
-        from poetry.utils.helpers import get_default_max_workers
+        from poetry.utils.helpers import get_max_workers
 
         unique_config_values = {
             "cache-dir": (
@@ -91,7 +91,7 @@ def unique_config_values(self) -> Dict[str, Tuple[Any, Any, Any]]:
             "installer.max-workers": (
                 lambda val: int(val) > 0,
                 lambda val: int(val),
-                get_default_max_workers(),
+                get_max_workers(),
             ),
         }
 
diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index add2bff78e4..dbdfc5050d4 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -13,6 +13,7 @@
 from typing import Dict
 from typing import List
 from typing import Union
+from typing import Optional
 
 from cleo.io.null_io import NullIO
 
@@ -23,7 +24,7 @@
 from poetry.core.pyproject.toml import PyProjectTOML
 from poetry.utils._compat import decode
 from poetry.utils.env import EnvCommandError
-from poetry.utils.helpers import get_default_max_workers
+from poetry.utils.helpers import get_max_workers
 from poetry.utils.helpers import safe_rmtree
 from poetry.utils.pip import pip_editable_install
 
@@ -55,7 +56,7 @@ def __init__(
         config: "Config",
         io: "IO",
         parallel: bool = None,
-        max_workers: int = None,
+        max_workers: Optional[int] = None,
     ) -> None:
         self._env = env
         self._io = io
@@ -70,12 +71,7 @@ def __init__(
             parallel = config.get("installer.parallel", True)
 
         if parallel:
-            self._max_workers = get_default_max_workers()
-
-            if max_workers is None:
-                max_workers = config.get("installer.max-workers", self._max_workers)
-
-            self._max_workers = min(max_workers, self._max_workers)
+            self._max_workers = config.get("installer.max-workers", get_max_workers(desired_max_workers=max_workers))
         else:
             self._max_workers = 1
 
diff --git a/poetry/utils/helpers.py b/poetry/utils/helpers.py
index 3c82450b2c2..ba2e7c6f5b6 100644
--- a/poetry/utils/helpers.py
+++ b/poetry/utils/helpers.py
@@ -143,7 +143,7 @@ def is_dir_writable(path: Path, create: bool = False) -> bool:
         return True
 
 
-def get_default_max_workers():
+def get_max_workers(desired_max_workers: Optional[int] = None):
     # This should be directly handled by ThreadPoolExecutor
     # however, on some systems the number of CPUs cannot be determined
     # (it raises a NotImplementedError), so, in this case, we assume
@@ -153,4 +153,6 @@ def get_default_max_workers():
     except NotImplementedError:
         default_max_workers = 5
 
-    return default_max_workers
+    if desired_max_workers is None:
+        return default_max_workers
+    return min(default_max_workers, desired_max_workers)

From ddb2a6587113878d18091b80854cb792cf32b209 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sun, 14 Nov 2021 13:12:07 +0000
Subject: [PATCH 06/11] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 poetry/installation/executor.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index dbdfc5050d4..7c05bfd011b 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -12,8 +12,8 @@
 from typing import Any
 from typing import Dict
 from typing import List
-from typing import Union
 from typing import Optional
+from typing import Union
 
 from cleo.io.null_io import NullIO
 
@@ -71,7 +71,10 @@ def __init__(
             parallel = config.get("installer.parallel", True)
 
         if parallel:
-            self._max_workers = config.get("installer.max-workers", get_max_workers(desired_max_workers=max_workers))
+            self._max_workers = config.get(
+                "installer.max-workers",
+                get_max_workers(desired_max_workers=max_workers),
+            )
         else:
             self._max_workers = 1
 

From 4aa81176aa4ee02d86fbf8e9073c81b7a123e55b Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sat, 20 Nov 2021 14:15:48 +0100
Subject: [PATCH 07/11] Update maximum worker logic

---
 .gitignore                          |  2 ++
 docs/configuration.md               |  5 +++++
 poetry/config/config.py             |  9 +++++++-
 poetry/console/commands/config.py   |  6 +++---
 poetry/installation/executor.py     | 22 +++++++++++++++-----
 poetry/utils/helpers.py             | 15 --------------
 tests/config/test_config.py         |  4 ++--
 tests/installation/test_executor.py | 32 +++++++++++++++++++++++++++++
 8 files changed, 69 insertions(+), 26 deletions(-)

diff --git a/.gitignore b/.gitignore
index fcbd92e97a3..0004c5bcc85 100644
--- a/.gitignore
+++ b/.gitignore
@@ -38,3 +38,5 @@ MANIFEST.in
 /releases/*
 pip-wheel-metadata
 /poetry.toml
+
+poetry/core/*
diff --git a/docs/configuration.md b/docs/configuration.md
index 19b988c969a..c93322310a1 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -128,6 +128,11 @@ Defaults to `true`.
 **Type**: int
 
 Set the maximum number of workers while using the parallel installer. Defaults to `number_of_cores + 4`.
+The `number_of_cores` is determined by `os.cpu_count()`.
+If this raises a `NotImplentedError` exception `number_of_cores` is assumed to be 1.
+
+If this configuration parameter is set to a value greater than `number_of_cores + 4`,
+the number of maximum workers is still limited at `number_of_cores + 4`.
 
 {{% note %}}
 This configuration will be ignored when `installer.parallel` is set to false.
diff --git a/poetry/config/config.py b/poetry/config/config.py
index b1b3b3e61bb..3f7a93872de 100644
--- a/poetry/config/config.py
+++ b/poetry/config/config.py
@@ -25,6 +25,10 @@ def boolean_normalizer(val: str) -> bool:
     return val in ["true", "1"]
 
 
+def int_normalizer(val: str) -> int:
+    return int(val)
+
+
 class Config:
 
     default_config = {
@@ -36,7 +40,7 @@ class Config:
             "options": {"always-copy": False, "system-site-packages": False},
         },
         "experimental": {"new-installer": True},
-        "installer": {"parallel": True},
+        "installer": {"parallel": True, "max-workers": None},
     }
 
     def __init__(
@@ -146,4 +150,7 @@ def _get_normalizer(self, name: str) -> Callable:
         if name == "virtualenvs.path":
             return lambda val: str(Path(val))
 
+        if name == "installer.max-workers":
+            return int_normalizer
+
         return lambda val: val
diff --git a/poetry/console/commands/config.py b/poetry/console/commands/config.py
index 799fd1a218e..95672b4ec16 100644
--- a/poetry/console/commands/config.py
+++ b/poetry/console/commands/config.py
@@ -52,8 +52,8 @@ def unique_config_values(self) -> Dict[str, Tuple[Any, Any, Any]]:
 
         from poetry.config.config import boolean_normalizer
         from poetry.config.config import boolean_validator
+        from poetry.config.config import int_normalizer
         from poetry.locations import CACHE_DIR
-        from poetry.utils.helpers import get_max_workers
 
         unique_config_values = {
             "cache-dir": (
@@ -90,8 +90,8 @@ def unique_config_values(self) -> Dict[str, Tuple[Any, Any, Any]]:
             ),
             "installer.max-workers": (
                 lambda val: int(val) > 0,
-                lambda val: int(val),
-                get_max_workers(),
+                int_normalizer,
+                None,
             ),
         }
 
diff --git a/poetry/installation/executor.py b/poetry/installation/executor.py
index 7c05bfd011b..18dc7ee70c9 100644
--- a/poetry/installation/executor.py
+++ b/poetry/installation/executor.py
@@ -24,7 +24,6 @@
 from poetry.core.pyproject.toml import PyProjectTOML
 from poetry.utils._compat import decode
 from poetry.utils.env import EnvCommandError
-from poetry.utils.helpers import get_max_workers
 from poetry.utils.helpers import safe_rmtree
 from poetry.utils.pip import pip_editable_install
 
@@ -56,7 +55,6 @@ def __init__(
         config: "Config",
         io: "IO",
         parallel: bool = None,
-        max_workers: Optional[int] = None,
     ) -> None:
         self._env = env
         self._io = io
@@ -71,9 +69,8 @@ def __init__(
             parallel = config.get("installer.parallel", True)
 
         if parallel:
-            self._max_workers = config.get(
-                "installer.max-workers",
-                get_max_workers(desired_max_workers=max_workers),
+            self._max_workers = self._get_max_workers(
+                desired_max_workers=config.get("installer.max-workers")
             )
         else:
             self._max_workers = 1
@@ -191,6 +188,21 @@ def execute(self, operations: List["OperationTypes"]) -> int:
 
         return 1 if self._shutdown else 0
 
+    @staticmethod
+    def _get_max_workers(desired_max_workers: Optional[int] = None):
+        # This should be directly handled by ThreadPoolExecutor
+        # however, on some systems the number of CPUs cannot be determined
+        # (it raises a NotImplementedError), so, in this case, we assume
+        # that the system only has one CPU.
+        try:
+            default_max_workers = os.cpu_count() + 4
+        except NotImplementedError:
+            default_max_workers = 5
+
+        if desired_max_workers is None:
+            return default_max_workers
+        return min(default_max_workers, desired_max_workers)
+
     def _write(self, operation: "OperationTypes", line: str) -> None:
         if not self.supports_fancy_output() or not self._should_write_operation(
             operation
diff --git a/poetry/utils/helpers.py b/poetry/utils/helpers.py
index ba2e7c6f5b6..a19874a0ce2 100644
--- a/poetry/utils/helpers.py
+++ b/poetry/utils/helpers.py
@@ -141,18 +141,3 @@ def is_dir_writable(path: Path, create: bool = False) -> bool:
         return False
     else:
         return True
-
-
-def get_max_workers(desired_max_workers: Optional[int] = None):
-    # This should be directly handled by ThreadPoolExecutor
-    # however, on some systems the number of CPUs cannot be determined
-    # (it raises a NotImplementedError), so, in this case, we assume
-    # that the system only has one CPU.
-    try:
-        default_max_workers = os.cpu_count() + 4
-    except NotImplementedError:
-        default_max_workers = 5
-
-    if desired_max_workers is None:
-        return default_max_workers
-    return min(default_max_workers, desired_max_workers)
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index 7727795ecfe..9f8f5237e52 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -19,8 +19,8 @@ def test_config_get_processes_depended_on_values(config, config_cache_dir):
     [
         ("installer.parallel", "true", True),
         ("installer.parallel", "false", False),
-        ("installer.max-workers", "4", "4"),
-        ("installer.max-workers", "2", "2"),
+        ("installer.max-workers", "4", 4),
+        ("installer.max-workers", "2", 2),
         ("virtualenvs.create", "true", True),
         ("virtualenvs.create", "false", False),
     ],
diff --git a/tests/installation/test_executor.py b/tests/installation/test_executor.py
index 5da4ef2d492..8b9fdcf03ac 100644
--- a/tests/installation/test_executor.py
+++ b/tests/installation/test_executor.py
@@ -494,3 +494,35 @@ def test_executor_should_use_cached_link_and_hash(
         Link("https://example.com/demo-0.1.0-py2.py3-none-any.whl"),
     )
     assert archive == link_cached
+
+
+@pytest.mark.parametrize(
+    ("max_workers", "cpu_count", "side_effect", "expected_workers"),
+    [
+        (None, 3, None, 7),
+        (3, 4, None, 3),
+        (8, 3, None, 7),
+        (None, 8, NotImplementedError(), 5),
+        (2, 8, NotImplementedError(), 2),
+        (8, 8, NotImplementedError(), 5),
+    ],
+)
+def test_executor_should_be_initialized_with_correct_workers(
+    tmp_venv,
+    pool,
+    config,
+    io,
+    mocker,
+    max_workers,
+    cpu_count,
+    side_effect,
+    expected_workers,
+):
+    config = Config()
+    config.merge({"installer": {"max-workers": max_workers}})
+
+    mocker.patch("os.cpu_count", return_value=cpu_count, side_effect=side_effect)
+
+    executor = Executor(tmp_venv, pool, config, io)
+
+    assert executor._max_workers == expected_workers

From 474e879db400181015ceebd065876de96502343a Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sat, 20 Nov 2021 14:50:10 +0100
Subject: [PATCH 08/11] Update test_config.py to include int tests

---
 tests/config/test_config.py | 41 +++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index 6f05056fb19..a1c662c305f 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -3,6 +3,7 @@
 
 from typing import TYPE_CHECKING
 from typing import Any
+from typing import Callable
 from typing import Dict
 from typing import Iterator
 from typing import Optional
@@ -11,22 +12,36 @@
 import pytest
 
 from poetry.config.config import Config
+from poetry.config.config import boolean_normalizer
+from poetry.config.config import int_normalizer
 
 
 if TYPE_CHECKING:
     from pathlib import Path
 
 
-def get_boolean_options(config: Optional[Dict[str, Any]] = None) -> str:
+def flatten(config: Optional[Dict[str, Any]], parent_key: str = "", sep="."):
+    items = []
+    for k, v in config.items():
+        new_key = parent_key + sep + k if parent_key else k
+        if isinstance(v, dict):
+            items.extend(flatten(v, new_key, sep=sep).items())
+        else:
+            items.append((new_key, v))
+    return dict(items)
+
+
+def get_options_based_on_normalizer(
+    normalizer: Callable, config: Optional[Config] = None
+) -> str:
     if config is None:
-        config = Config.default_config
+        config = Config()
 
-    for k, v in config.items():
-        if isinstance(v, bool) or v is None:
+    flattened_config = flatten(config.default_config)
+
+    for k in flattened_config:
+        if config._get_normalizer(k) == normalizer:
             yield k
-        if isinstance(v, dict):
-            for suboption in get_boolean_options(v):
-                yield f"{k}.{suboption}"
 
 
 @pytest.mark.parametrize(
@@ -43,10 +58,14 @@ def test_config_get_processes_depended_on_values(
 
 
 def generate_environment_variable_tests() -> Iterator[Tuple[str, str, str, bool]]:
-    for env_value, value in [("true", True), ("false", False)]:
-        for name in get_boolean_options():
-            env_var = "POETRY_{}".format(re.sub("[.-]+", "_", name).upper())
-            yield name, env_var, env_value, value
+    for normalizer, values in [
+        (boolean_normalizer, [("true", True), ("false", False)]),
+        (int_normalizer, [("4", 4), ("2", 2)]),
+    ]:
+        for env_value, value in values:
+            for name in get_options_based_on_normalizer(normalizer=normalizer):
+                env_var = "POETRY_{}".format(re.sub("[.-]+", "_", name).upper())
+                yield name, env_var, env_value, value
 
 
 @pytest.mark.parametrize(

From ed0b4a73d1633b448a9b934d757596dbb860acdd Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sat, 20 Nov 2021 15:03:23 +0100
Subject: [PATCH 09/11] Fix tests

---
 tests/console/commands/test_config.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/console/commands/test_config.py b/tests/console/commands/test_config.py
index 8d9620b1b28..d4a2dfec857 100644
--- a/tests/console/commands/test_config.py
+++ b/tests/console/commands/test_config.py
@@ -46,6 +46,7 @@ def test_list_displays_default_value_if_not_set(
 
     expected = """cache-dir = {cache}
 experimental.new-installer = true
+installer.max-workers = null
 installer.parallel = true
 virtualenvs.create = true
 virtualenvs.in-project = null
@@ -70,6 +71,7 @@ def test_list_displays_set_get_setting(
 
     expected = """cache-dir = {cache}
 experimental.new-installer = true
+installer.max-workers = null
 installer.parallel = true
 virtualenvs.create = false
 virtualenvs.in-project = null
@@ -118,6 +120,7 @@ def test_list_displays_set_get_local_setting(
 
     expected = """cache-dir = {cache}
 experimental.new-installer = true
+installer.max-workers = null
 installer.parallel = true
 virtualenvs.create = false
 virtualenvs.in-project = null

From 2e724ae8cf5e7e30efc93afc923eb2e4bab3a6dc Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 21 Nov 2021 16:08:30 +0100
Subject: [PATCH 10/11] Address PR comments

---
 poetry.lock                 | 13 ++++++++++++-
 pyproject.toml              |  1 +
 tests/config/test_config.py | 28 ++++++----------------------
 3 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/poetry.lock b/poetry.lock
index e1987a36d8c..36b6f769f8b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -211,6 +211,14 @@ python-versions = ">=3.6"
 docs = ["furo (>=2021.8.17b43)", "sphinx (>=4.1)", "sphinx-autodoc-typehints (>=1.12)"]
 testing = ["covdefaults (>=1.2.0)", "coverage (>=4)", "pytest (>=4)", "pytest-cov", "pytest-timeout (>=1.4.2)"]
 
+[[package]]
+name = "flatdict"
+version = "4.0.1"
+description = "Python module for interacting with nested dicts as a single level dict with delimited keys."
+category = "dev"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "html5lib"
 version = "1.1"
@@ -739,7 +747,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytes
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.6"
-content-hash = "9d2e32899df46f2c63018e9a3f5e95dbbeb1ec41291c31289cff40f6f2d935a4"
+content-hash = "d427df125a868ada92bbb6d3a8cc90def6034ad684c1546afb519729048ab150"
 
 [metadata.files]
 atomicwrites = [
@@ -929,6 +937,9 @@ filelock = [
     {file = "filelock-3.4.0-py3-none-any.whl", hash = "sha256:2e139a228bcf56dd8b2274a65174d005c4a6b68540ee0bdbb92c76f43f29f7e8"},
     {file = "filelock-3.4.0.tar.gz", hash = "sha256:93d512b32a23baf4cac44ffd72ccf70732aeff7b8050fcaf6d3ec406d954baf4"},
 ]
+flatdict = [
+    {file = "flatdict-4.0.1.tar.gz", hash = "sha256:cd32f08fd31ed21eb09ebc76f06b6bd12046a24f77beb1fd0281917e47f26742"},
+]
 html5lib = [
     {file = "html5lib-1.1-py2.py3-none-any.whl", hash = "sha256:0d78f8fde1c230e99fe37986a60526d7049ed4bf8a9fadbad5f00e22e58e041d"},
     {file = "html5lib-1.1.tar.gz", hash = "sha256:b2e5b40261e20f354d198eae92afc10d750afb487ed5e50f9c4eaf07c184146f"},
diff --git a/pyproject.toml b/pyproject.toml
index 4ff1a3f4420..0dc64b4877c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,6 +65,7 @@ deepdiff = "^5.0"
 httpretty = "^1.0"
 typing-extensions = { version = "^4.0.0", python = "<3.8" }
 zipp = { version = "^3.4", python = "<3.8" }
+flatdict = "^4.0.1"
 
 [tool.poetry.scripts]
 poetry = "poetry.console.application:main"
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index a1c662c305f..5a9e9477318 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -2,15 +2,14 @@
 import re
 
 from typing import TYPE_CHECKING
-from typing import Any
 from typing import Callable
-from typing import Dict
 from typing import Iterator
-from typing import Optional
 from typing import Tuple
 
 import pytest
 
+from flatdict import FlatDict
+
 from poetry.config.config import Config
 from poetry.config.config import boolean_normalizer
 from poetry.config.config import int_normalizer
@@ -20,24 +19,9 @@
     from pathlib import Path
 
 
-def flatten(config: Optional[Dict[str, Any]], parent_key: str = "", sep="."):
-    items = []
-    for k, v in config.items():
-        new_key = parent_key + sep + k if parent_key else k
-        if isinstance(v, dict):
-            items.extend(flatten(v, new_key, sep=sep).items())
-        else:
-            items.append((new_key, v))
-    return dict(items)
-
-
-def get_options_based_on_normalizer(
-    normalizer: Callable, config: Optional[Config] = None
-) -> str:
-    if config is None:
-        config = Config()
-
-    flattened_config = flatten(config.default_config)
+def get_options_based_on_normalizer(normalizer: Callable) -> str:
+    config = Config()
+    flattened_config = FlatDict(config.default_config, delimiter=".")
 
     for k in flattened_config:
         if config._get_normalizer(k) == normalizer:
@@ -64,7 +48,7 @@ def generate_environment_variable_tests() -> Iterator[Tuple[str, str, str, bool]
     ]:
         for env_value, value in values:
             for name in get_options_based_on_normalizer(normalizer=normalizer):
-                env_var = "POETRY_{}".format(re.sub("[.-]+", "_", name).upper())
+                env_var = "POETRY_" + re.sub("[.-]+", "_", name).upper()
                 yield name, env_var, env_value, value
 
 

From d05ef885803eb3edc896eb8941cf429f73ee8802 Mon Sep 17 00:00:00 2001
From: Maximilian Speicher <maximilian.speicher@tum.de>
Date: Sun, 21 Nov 2021 20:56:59 +0100
Subject: [PATCH 11/11] Make _get_normalizer static

---
 src/poetry/config/config.py | 3 ++-
 tests/config/test_config.py | 5 ++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/poetry/config/config.py b/src/poetry/config/config.py
index 011a556c8ff..720e479f48f 100644
--- a/src/poetry/config/config.py
+++ b/src/poetry/config/config.py
@@ -133,7 +133,8 @@ def process(self, value: Any) -> Any:
 
         return re.sub(r"{(.+?)}", lambda m: self.get(m.group(1)), value)
 
-    def _get_normalizer(self, name: str) -> Callable:
+    @staticmethod
+    def _get_normalizer(name: str) -> Callable:
         if name in {
             "virtualenvs.create",
             "virtualenvs.in-project",
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index 5a9e9477318..0f8c237c27d 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -20,11 +20,10 @@
 
 
 def get_options_based_on_normalizer(normalizer: Callable) -> str:
-    config = Config()
-    flattened_config = FlatDict(config.default_config, delimiter=".")
+    flattened_config = FlatDict(Config.default_config, delimiter=".")
 
     for k in flattened_config:
-        if config._get_normalizer(k) == normalizer:
+        if Config._get_normalizer(k) == normalizer:
             yield k