From 128c528f392cd79b3f19f0dbf09b6e4c74809e2a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Randy=20D=C3=B6ring?=
 <30527984+radoering@users.noreply.github.com>
Date: Mon, 12 Dec 2022 05:51:50 +0100
Subject: [PATCH] solver: fix a special case with unconditional dependency of
 an extra (#7175)

Co-authored-by: David Hotham <david.hotham@blueyonder.co.uk>
---
 src/poetry/puzzle/provider.py | 18 ++++++----------
 src/poetry/puzzle/solver.py   | 10 ++++++++-
 tests/puzzle/test_solver.py   | 39 +++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 13 deletions(-)

diff --git a/src/poetry/puzzle/provider.py b/src/poetry/puzzle/provider.py
index cfb50d43b4a..69302a94acb 100644
--- a/src/poetry/puzzle/provider.py
+++ b/src/poetry/puzzle/provider.py
@@ -20,6 +20,7 @@
 from poetry.core.constraints.version import Version
 from poetry.core.packages.utils.utils import get_python_constraint_from_marker
 from poetry.core.version.markers import AnyMarker
+from poetry.core.version.markers import EmptyMarker
 from poetry.core.version.markers import MarkerUnion
 
 from poetry.inspection.info import PackageInfo
@@ -946,20 +947,13 @@ def _merge_dependencies_by_constraint(
         for dep in dependencies:
             by_constraint[dep.constraint].append(dep)
         for constraint, _deps in by_constraint.items():
-            new_markers = []
-            for dep in _deps:
-                marker = dep.marker.without_extras()
-                if marker.is_any():
-                    # No marker or only extras
-                    continue
-
-                new_markers.append(marker)
-
-            if not new_markers:
-                continue
+            new_markers = [dep.marker for dep in _deps]
 
             dep = _deps[0]
-            dep.marker = dep.marker.union(MarkerUnion(*new_markers))
+
+            # Union with EmptyMarker is to make sure we get the benefit of marker
+            # simplifications.
+            dep.marker = MarkerUnion(*new_markers).union(EmptyMarker())
             by_constraint[constraint] = [dep]
 
         return [value[0] for value in by_constraint.values()]
diff --git a/src/poetry/puzzle/solver.py b/src/poetry/puzzle/solver.py
index d38a2e0c277..66e1aca6a5b 100644
--- a/src/poetry/puzzle/solver.py
+++ b/src/poetry/puzzle/solver.py
@@ -181,8 +181,16 @@ def _solve(self) -> tuple[list[Package], list[int]]:
                             if _package.name == dep.name:
                                 continue
 
-                            if dep not in _package.requires:
+                            try:
+                                index = _package.requires.index(dep)
+                            except ValueError:
                                 _package.add_dependency(dep)
+                            else:
+                                _dep = _package.requires[index]
+                                if _dep.marker != dep.marker:
+                                    # marker of feature package is more accurate
+                                    # because it includes relevant extras
+                                    _dep.marker = dep.marker
             else:
                 final_packages.append(package)
                 depths.append(results[package])
diff --git a/tests/puzzle/test_solver.py b/tests/puzzle/test_solver.py
index 04f2dd70b35..0018da79da5 100644
--- a/tests/puzzle/test_solver.py
+++ b/tests/puzzle/test_solver.py
@@ -791,6 +791,45 @@ def test_solver_merge_extras_into_base_package_multiple_repos_fixes_5727(
     assert len(ops[0].package.requires) == 0, "a should not require itself"
 
 
+def test_solver_returns_extras_if_excluded_by_markers_without_extras(
+    solver: Solver, repo: Repository, package: ProjectPackage
+):
+    package.add_dependency(
+        Factory.create_dependency("A", {"version": "*", "extras": ["foo"]})
+    )
+
+    package_a = get_package("A", "1.0")
+    package_b = get_package("B", "1.0")
+
+    # mandatory dependency with marker
+    dep = get_dependency("B", "^1.0")
+    dep.marker = parse_marker("sys_platform != 'linux'")
+    package_a.add_dependency(dep)
+
+    # optional dependency with same constraint and no marker except for extra
+    dep = get_dependency("B", "^1.0", optional=True)
+    dep.marker = parse_marker("extra == 'foo'")
+    package_a.extras = {"foo": [dep]}
+    package_a.add_dependency(dep)
+
+    repo.add_package(package_a)
+    repo.add_package(package_b)
+
+    transaction = solver.solve()
+
+    ops = check_solver_result(
+        transaction,
+        [
+            {"job": "install", "package": package_b},
+            {"job": "install", "package": package_a},
+        ],
+    )
+    assert (
+        str(ops[1].package.requires[0].marker)
+        == 'sys_platform != "linux" or extra == "foo"'
+    )
+
+
 def test_solver_returns_prereleases_if_requested(
     solver: Solver, repo: Repository, package: ProjectPackage
 ):