feat: add support for removal of packages from a registryfix/support-removed-packages

This adds support for removal of packages from any given registry.
Currently mason.nvim doesn't support this at all and throws an error
when trying to interact with the registry in any way while having a
removed package installed locally.

This ensures that removed packages are available both in the `:Mason` UI
as well as the public Lua APIs. These "synthesized" packages only
supports uninstallation, and metadata such as licenses, categories,
homepage, etc is not available.

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/mason-registry/sources/collection_spec.lua b/tests/mason-registry/sources/collection_spec.lua
index b603c868..a5253ab5 100644
--- a/tests/mason-registry/sources/collection_spec.lua
+++ b/tests/mason-registry/sources/collection_spec.lua
@@ -1,4 +1,5 @@
 local LazySourceCollection = require "mason-registry.sources"
+local SynthesizedSource = require "mason-registry.sources.synthesized"
 
 describe("LazySourceCollection", function()
     it("should dedupe registries on append/prepend", function()
@@ -18,4 +19,22 @@ describe("LazySourceCollection", function()
         assert.same("github:mason-org/mason-registry@2025-05-16", coll:get(3):get_full_id())
         assert.same("file:~/registry", coll:get(4):get_full_id())
     end)
+
+    it("should fall back to synthesized source", function()
+        local coll = LazySourceCollection:new()
+
+        for source in coll:iterate() do
+            assert.is_true(getmetatable(source) == SynthesizedSource)
+            return
+        end
+        error "Did not fall back to synthesized source"
+    end)
+
+    it("should exclude synthesized source", function()
+        local coll = LazySourceCollection:new()
+
+        for source in coll:iterate { include_synthesized = false } do
+            error "Should not iterate."
+        end
+    end)
 end)