Merge pull request #22351 from dariaguy/install-renamed-src-realpath

Resolve src through realpath in install_renamed

Author: MikeMcQuaid

Library/Homebrew/install_renamed.rb

@@ -48,6 +48,14 @@ def append_default_if_different(src, dst)
     # helper. If the live config still matches an older bottled default, replace
     # it so untouched configs advance on upgrade. Modified configs still receive
     # the new default as `*.default`.
+    # Resolve via realpath so the ascend walks the Cellar path, not `opt_prefix`.
+    # For symlink sources, resolve only the parent directory so broken symlinks
+    # are still handled without requiring the target to exist.
+    src = if src.symlink?
+      src.dirname.realpath/src.basename
+    else
+      src.realpath
+    end
     src.ascend do |path|
       next if path.basename.to_s != ".bottle" || path.parent.parent.parent != HOMEBREW_CELLAR
 

Library/Homebrew/test/formula_spec.rb

@@ -1121,6 +1121,15 @@ def post_install
 
       expect([config_file.read, default_config_file.read]).to eq(["custom\n", "new\n"])
     end
+
+    it "replaces config that matches the previous default when the keg is opt-linked" do
+      config_file.write "old\n"
+      Keg.new(f.rack/"2.0").optlink
+
+      f.install_etc_var
+
+      expect([config_file.read, default_config_file.exist?]).to eq(["new\n", false])
+    end
   end
 
   specify "test fixtures" do