Formula: use opt_prefix for service helpers

Library/Homebrew/formula.rb

@@ -986,13 +986,13 @@ class Formula
   # The generated launchd {.plist} file path.
   sig { returns(Pathname) }
   def plist_path
-    prefix/"#{plist_name}.plist"
+    opt_prefix/"#{plist_name}.plist"
   end
 
   # The generated systemd {.service} file path.
   sig { returns(Pathname) }
   def systemd_service_path
-    prefix/"#{service_name}.service"
+    opt_prefix/"#{service_name}.service"
   end
 
   # The service specification of the software.

Library/Homebrew/test/formula_installer_spec.rb

@@ -223,7 +223,7 @@ describe FormulaInstaller do
     it "works if plist is set" do
       formula = Testball.new
       path = formula.plist_path
-      formula.prefix.mkpath
+      formula.opt_prefix.mkpath
 
       expect(formula).to receive(:plist).twice.and_return("PLIST")
       expect(formula).to receive(:plist_path).and_call_original
@@ -241,7 +241,7 @@ describe FormulaInstaller do
       plist_path = formula.plist_path
       service_path = formula.systemd_service_path
       service = Homebrew::Service.new(formula)
-      formula.prefix.mkpath
+      formula.opt_prefix.mkpath
 
       expect(formula).to receive(:plist).and_return(nil)
       expect(formula).to receive(:service?).exactly(3).and_return(true)
@@ -264,7 +264,7 @@ describe FormulaInstaller do
     it "returns without definition" do
       formula = Testball.new
       path = formula.plist_path
-      formula.prefix.mkpath
+      formula.opt_prefix.mkpath
 
       expect(formula).to receive(:plist).and_return(nil)
       expect(formula).to receive(:service?).exactly(3).and_return(nil)
@@ -282,7 +282,7 @@ describe FormulaInstaller do
     it "errors with duplicate definition" do
       formula = Testball.new
       path = formula.plist_path
-      formula.prefix.mkpath
+      formula.opt_prefix.mkpath
 
       expect(formula).to receive(:plist).and_return("plist")
       expect(formula).to receive(:service?).and_return(true)

Library/Homebrew/test/formula_spec.rb

@@ -701,7 +701,16 @@ describe Formula do
     end
   end
 
-  specify "#service" do
+  describe "#service" do
+    specify "no service defined" do
+      f = formula do
+        url "https://brew.sh/test-1.0.tbz"
+      end
+
+      expect(f.service).to eq(nil)
+    end
+
+    specify "service complicated" do
       f = formula do
         url "https://brew.sh/test-1.0.tbz"
       end
@@ -728,6 +737,18 @@ describe Formula do
       expect(f.service).not_to eq(nil)
     end
 
+    specify "service helpers return data" do
+      f = formula do
+        url "https://brew.sh/test-1.0.tbz"
+      end
+
+      expect(f.plist_name).to eq("homebrew.mxcl.formula_name")
+      expect(f.service_name).to eq("homebrew.formula_name")
+      expect(f.plist_path).to eq(HOMEBREW_PREFIX/"opt/formula_name/homebrew.mxcl.formula_name.plist")
+      expect(f.systemd_service_path).to eq(HOMEBREW_PREFIX/"opt/formula_name/homebrew.formula_name.service")
+    end
+  end
+
   specify "dependencies" do
     f1 = formula "f1" do
       url "f1-1.0"