fix: make it a preference, not a fix

Author: IanButterworth

src/Resolve/maxsum.jl

@@ -1,7 +1,10 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 const DEFAULT_MAX_TIME = "300"
-const PREFERRED_VERSION_WEIGHT_BONUS = VersionWeight(typemax(Int32))
+# Prefer loaded versions, but not so strongly that it overrides compatibility constraints.
+# This bonus is added to the version weight of already-loaded packages, making them more
+# favorable than other versions but not creating hard requirements.
+const PREFERRED_VERSION_WEIGHT_BONUS = VersionWeight(100, 0, 0)
 
 # Some parameters to drive the decimation process
 mutable struct MaxSumParams

test/registry.jl

@@ -431,13 +431,13 @@ end
         # Tests that [email protected] does not get installed
         temp_pkg_dir() do env
             Pkg.Registry.add(url = "https://github.com/JuliaRegistries/Test")
-            Pkg.add("Example"; prefer_loaded_versions = false)
+            Pkg.add("Example")
             @test manifest_info(EnvCache().manifest, uuid).version == v"0.5.0"
             Pkg.update() # should not update Example
             @test manifest_info(EnvCache().manifest, uuid).version == v"0.5.0"
             @test_throws Pkg.Resolve.ResolverError Pkg.add(PackageSpec(name = "Example", version = v"0.5.1"))
             Pkg.rm("Example")
-            Pkg.add("JSON"; prefer_loaded_versions = false) # depends on Example
+            Pkg.add("JSON") # depends on Example
             @test manifest_info(EnvCache().manifest, uuid).version == v"0.5.0"
             Pkg.update()
             @test manifest_info(EnvCache().manifest, uuid).version == v"0.5.0"