From 64cce29ec2bd0a0c650683526f8930426576db17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Randy=20D=C3=B6ring?=
 <30527984+radoering@users.noreply.github.com>
Date: Sat, 25 Jan 2025 18:01:35 +0100
Subject: [PATCH] improve performance for merging marker overrides - volume 2

---
 src/poetry/puzzle/solver.py           | 31 ++++++++++++++---
 tests/puzzle/test_solver_internals.py | 48 +++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/src/poetry/puzzle/solver.py b/src/poetry/puzzle/solver.py
index 7bbce2e4b5b..3bb4c43851d 100644
--- a/src/poetry/puzzle/solver.py
+++ b/src/poetry/puzzle/solver.py
@@ -9,6 +9,8 @@
 
 from poetry.core.version.markers import AnyMarker
 from poetry.core.version.markers import EmptyMarker
+from poetry.core.version.markers import MultiMarker
+from poetry.core.version.markers import SingleMarker
 from poetry.core.version.markers import parse_marker
 
 from poetry.mixology import resolve_version
@@ -428,11 +430,20 @@ def merge_override_packages(
             for dep in deps.values():
                 override_marker = override_marker.intersect(dep.marker.without_extras())
         for package, info in o_packages.items():
+            for group, marker in info.markers.items():
+                # `override_marker` is often a SingleMarker or a MultiMarker,
+                # `marker` often is a MultiMarker that contains override_marker.
+                # We can "remove" the `override_marker` from `marker`
+                # because we will do an intersection later anyway.
+                # By removing it now, it is more likely that we hit
+                # the performance shortcut instead of the fallback algorithm.
+                info.markers[group] = remove_other_from_marker(marker, override_marker)
             all_packages.setdefault(package, []).append(
                 (package, info, override_marker)
             )
     for package_duplicates in all_packages.values():
         base = package_duplicates[0]
+        remaining = package_duplicates[1:]
         package = base[0]
         package_info = base[1]
         first_override_marker = base[2]
@@ -441,9 +452,7 @@ def merge_override_packages(
         package_info.groups = {
             g for _, info, _ in package_duplicates for g in info.groups
         }
-        if all(
-            info.markers == package_info.markers for _, info, _ in package_duplicates
-        ):
+        if all(info.markers == package_info.markers for _, info, _ in remaining):
             # performance shortcut:
             # if markers are the same for all overrides,
             # we can use less expensive marker operations
@@ -458,18 +467,30 @@ def merge_override_packages(
             # fallback / general algorithm with performance issues
             for group, marker in package_info.markers.items():
                 package_info.markers[group] = first_override_marker.intersect(marker)
-            for _, info, override_marker in package_duplicates[1:]:
+            for _, info, override_marker in remaining:
                 for group, marker in info.markers.items():
                     package_info.markers[group] = package_info.markers.get(
                         group, EmptyMarker()
                     ).union(override_marker.intersect(marker))
-        for duplicate_package, _, _ in package_duplicates[1:]:
+        for duplicate_package, _, _ in remaining:
             for dep in duplicate_package.requires:
                 if dep not in package.requires:
                     package.add_dependency(dep)
     return result
 
 
+def remove_other_from_marker(marker: BaseMarker, other: BaseMarker) -> BaseMarker:
+    if isinstance(other, SingleMarker):
+        other_markers: set[BaseMarker] = {other}
+    elif isinstance(other, MultiMarker):
+        other_markers = set(other.markers)
+    else:
+        return marker
+    if isinstance(marker, MultiMarker) and other_markers.issubset(marker.markers):
+        return MultiMarker.of(*(m for m in marker.markers if m not in other_markers))
+    return marker
+
+
 @functools.cache
 def simplify_marker(
     marker: BaseMarker, python_constraint: VersionConstraint
diff --git a/tests/puzzle/test_solver_internals.py b/tests/puzzle/test_solver_internals.py
index 9cfbac30da6..5fa07a26628 100644
--- a/tests/puzzle/test_solver_internals.py
+++ b/tests/puzzle/test_solver_internals.py
@@ -513,4 +513,52 @@ def test_merge_override_packages_groups(package: ProjectPackage) -> None:
     }
 
 
+def test_merge_override_packages_shortcut(package: ProjectPackage) -> None:
+    a = Package("a", "1")
+    common_marker = (
+        'extra == "test" and sys_platform == "win32" or platform_system == "Windows"'
+        ' or sys_platform == "linux" and extra == "stretch"'
+    )
+    override_marker1 = 'python_version >= "3.12" and platform_system != "Emscripten"'
+    override_marker2 = 'python_version >= "3.12" and platform_system == "Emscripten"'
+
+    packages = merge_override_packages(
+        [
+            (
+                {package: {"a": dep("b", override_marker1)}},
+                {
+                    a: TransitivePackageInfo(
+                        0,
+                        {"main"},
+                        {
+                            "main": parse_marker(
+                                f"{override_marker1} and ({common_marker})"
+                            )
+                        },
+                    )
+                },
+            ),
+            (
+                {package: {"a": dep("b", override_marker2)}},
+                {
+                    a: TransitivePackageInfo(
+                        0,
+                        {"main"},
+                        {
+                            "main": parse_marker(
+                                f"{override_marker2} and ({common_marker})"
+                            )
+                        },
+                    )
+                },
+            ),
+        ]
+    )
+    assert len(packages) == 1
+    assert packages[a].groups == {"main"}
+    assert tm(packages[a]) == {
+        "main": f'({common_marker}) and python_version >= "3.12"'
+    }
+
+
 # TODO: root extras