From 89ab70daea0e1bf77eb8310a42fb7312a8076d0f Mon Sep 17 00:00:00 2001
From: Paul Moore <p.f.moore@gmail.com>
Date: Fri, 19 Jan 2024 10:24:56 +0000
Subject: [PATCH 1/2] Allow creating a SpecifierSet from a list of specifiers

---
 CHANGELOG.rst               |  1 +
 src/packaging/specifiers.py | 21 +++++++++++++++------
 tests/test_specifiers.py    |  6 ++++++
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 153c2af6..73568358 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -14,6 +14,7 @@ Changelog
   have not been provided (:issue:`733`)
 * Fix a bug preventing the use of the built in ``ExceptionGroup`` on versions of
   Python that support it (:issue:`725`)
+* Support creating a ``SpecifierSet`` from an iterable of ``Specifier`` objects (:issue:`775`)
 
 23.2 - 2023-10-01
 ~~~~~~~~~~~~~~~~~
diff --git a/src/packaging/specifiers.py b/src/packaging/specifiers.py
index 2d015bab..3f88fd12 100644
--- a/src/packaging/specifiers.py
+++ b/src/packaging/specifiers.py
@@ -701,13 +701,17 @@ class SpecifierSet(BaseSpecifier):
     """
 
     def __init__(
-        self, specifiers: str = "", prereleases: Optional[bool] = None
+        self,
+        specifiers: Union[str, Iterable[Specifier]] = "",
+        prereleases: Optional[bool] = None,
     ) -> None:
         """Initialize a SpecifierSet instance.
 
         :param specifiers:
             The string representation of a specifier or a comma-separated list of
             specifiers which will be parsed and normalized before use.
+            May also be an iterable of ``Specifier`` instances, which will be used
+            as is.
         :param prereleases:
             This tells the SpecifierSet if it should accept prerelease versions if
             applicable or not. The default of ``None`` will autodetect it from the
@@ -718,12 +722,17 @@ def __init__(
             raised.
         """
 
-        # Split on `,` to break each individual specifier into it's own item, and
-        # strip each item to remove leading/trailing whitespace.
-        split_specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]
+        if isinstance(specifiers, str):
+            # Split on `,` to break each individual specifier into its own item, and
+            # strip each item to remove leading/trailing whitespace.
+            split_specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]
 
-        # Make each individual specifier a Specifier and save in a frozen set for later.
-        self._specs = frozenset(map(Specifier, split_specifiers))
+            # Make each individual specifier a Specifier and save in a frozen set
+            # for later.
+            self._specs = frozenset(map(Specifier, split_specifiers))
+        else:
+            # Save the supplied specifiers in a frozen set.
+            self._specs = frozenset(specifiers)
 
         # Store our prereleases value so we can use it later to determine if
         # we accept prereleases or not.
diff --git a/tests/test_specifiers.py b/tests/test_specifiers.py
index a79b860e..de360981 100644
--- a/tests/test_specifiers.py
+++ b/tests/test_specifiers.py
@@ -650,6 +650,12 @@ def test_empty_specifier(self, version):
         assert parse(version) in spec
         assert spec.contains(parse(version))
 
+    def test_create_from_specifiers(self):
+        spec_strs = [">=1.0", "!=1.1", "!=1.2", "<2.0"]
+        specs = [Specifier(s) for s in spec_strs]
+        spec = SpecifierSet(iter(specs))
+        assert set(spec) == set(specs)
+
     def test_specifier_prereleases_explicit(self):
         spec = SpecifierSet()
         assert not spec.prereleases

From 805bf15ddf954101208d281bb2d20b7116d896e7 Mon Sep 17 00:00:00 2001
From: Paul Moore <p.f.moore@gmail.com>
Date: Thu, 8 Aug 2024 09:28:52 +0100
Subject: [PATCH 2/2] Change from Union to | in type annotation

---
 src/packaging/specifiers.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/packaging/specifiers.py b/src/packaging/specifiers.py
index 54a12238..5fe042b3 100644
--- a/src/packaging/specifiers.py
+++ b/src/packaging/specifiers.py
@@ -696,7 +696,7 @@ class SpecifierSet(BaseSpecifier):
 
     def __init__(
         self,
-        specifiers: Union[str, Iterable[Specifier]] = "",
+        specifiers: str | Iterable[Specifier] = "",
         prereleases: bool | None = None,
     ) -> None:
         """Initialize a SpecifierSet instance.