Stable marker string

Fix #7

pdm/installers.py

@@ -53,10 +53,10 @@ class Installer:
     def install(self, candidate: Candidate) -> None:
         context.io.echo(f"Installing {candidate.format()}...")
         candidate.get_metadata()
-        if candidate.wheel:
-            self.install_wheel(candidate.wheel)
-        else:
+        if candidate.req.editable:
             self.install_editable(candidate.ireq)
+        else:
+            self.install_wheel(candidate.wheel)
 
     def install_wheel(self, wheel: Wheel) -> None:
         paths = self.environment.get_paths()

pdm/models/candidates.py

@@ -178,7 +178,7 @@ class Candidate:
     def as_lockfile_entry(self) -> Dict[str, Any]:
         result = {
             "name": self.name,
-            "sections": self.sections,
+            "sections": sorted(self.sections),
             "version": str(self.version),
             "extras": sorted(self.req.extras or ()),
             "marker": str(self.marker) if self.marker else None,

pdm/models/specifiers.py

@@ -373,7 +373,7 @@ class PySpecSet(SpecifierSet):
         result = []
         excludes = []
         full_excludes = []
-        for spec in self:
+        for spec in sorted(self, key=lambda spec: spec.version):
             op, version = spec.operator, spec.version
             if len(version.split(".")) < 3:
                 key = "python_version"