fix: allow prereleases when the requirement is pinned even if disabled by project

news/3202.bugfix.md

@@ -0,0 +1 @@
+Allow prereleases when the requirement is pinned even if disabled by project

src/pdm/resolver/providers.py

@@ -184,6 +184,8 @@ def _find_candidates(self, requirement: Requirement) -> Iterable[Candidate]:
             return [can]
         else:
             prerelease = requirement.prerelease
+            if prerelease is None and requirement.is_pinned and requirement.specifier.prereleases:
+                prerelease = True
             if prerelease is None and (key := requirement.identify()) in self.locked_candidates:
                 # keep the prerelease if it is locked
                 candidates = self.locked_candidates[key]
@@ -265,8 +267,10 @@ def is_satisfied_by(self, requirement: Requirement, candidate: Candidate) -> boo
             # This should be a URL candidate or self package, consider it to be matching
             return True
         # Allow prereleases if: 1) it is not specified in the tool settings or
-        # 2) the candidate doesn't come from PyPI index.
-        allow_prereleases = self.allow_prereleases in (True, None) or not candidate.req.is_named
+        # 2) the candidate doesn't come from PyPI index or 3) the requirement is pinned
+        allow_prereleases = (
+            self.allow_prereleases in (True, None) or not candidate.req.is_named or requirement.is_pinned
+        )
         return requirement.specifier.contains(version, allow_prereleases)
 
     def get_dependencies(self, candidate: Candidate) -> list[Requirement]:

tests/resolver/test_resolve.py

@@ -120,6 +120,11 @@ def test_resolve_allow_prereleases(resolve, repository):
         resolve(["bar"], allow_prereleases=False)
 
 
+def test_resolve_prereleases_if_disabled_by_project(resolve):
+    result = resolve(["urllib3==1.23b0"], allow_prereleases=False)
+    assert result["urllib3"].version == "1.23b0"
+
+
 def test_resolve_with_extras(resolve):
     result = resolve(["requests[socks]"])
     assert result["pysocks"].version == "1.5.6"