utils: add check_binary_linkage function

Library/Homebrew/test/utils/linkage_spec.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "utils/linkage"
+
+RSpec.describe Utils do
+  suffix = OS.mac? ? ".dylib" : ".so"
+
+  describe "::binary_linked_to_library?", :integration_test do
+    before do
+      install_test_formula "testball-linkage", <<~RUBY
+        def install
+          (buildpath/"foo.h").write "void foo();"
+          (buildpath/"foo.c").write <<~C
+            #include <stdio.h>
+            #include "foo.h"
+            void foo() { printf("foo\\\\n"); }
+          C
+          (buildpath/"bar.c").write <<~C
+            #include <stdio.h>
+            void bar() { printf("bar\\\\n"); }
+          C
+          (buildpath/"test.c").write <<~C
+            #include "foo.h"
+            int main() { foo(); return 0; }
+          C
+          system ENV.cc, "-c", "-fpic", "foo.c"
+          system ENV.cc, "-c", "-fpic", "bar.c"
+          dll_flag = OS.mac? ? "-dynamiclib" : "-shared"
+          system ENV.cc, dll_flag, "-o", shared_library("libbrewfoo"), "foo.o"
+          system ENV.cc, dll_flag, "-o", shared_library("libbrewbar"), "bar.o"
+          lib.install shared_library("libbrewfoo"), shared_library("libbrewbar")
+          system ENV.cc, "-o", "brewtest", "test.c", "-L\#{lib}", "-lbrewfoo"
+          bin.install "brewtest"
+        end
+      RUBY
+    end
+
+    it "returns true if the binary is linked to the library" do
+      f = Formula["testball-linkage"]
+      result = described_class.binary_linked_to_library?(f.bin/"brewtest",
+                                                         f.lib/"libbrewfoo#{suffix}", HOMEBREW_CELLAR)
+      expect(result).to be true
+    end
+
+    it "returns false if the binary is not linked to the library" do
+      f = Formula["testball-linkage"]
+      result = described_class.binary_linked_to_library?(f.bin/"brewtest",
+                                                         f.lib/"libbrewbar#{suffix}", HOMEBREW_CELLAR)
+      expect(result).to be false
+    end
+  end
+end

Library/Homebrew/utils/linkage.rb

@@ -0,0 +1,16 @@
+# typed: strict
+# frozen_string_literal: true
+
+module Utils
+  sig {
+    params(binary: T.any(String, Pathname), library: T.any(String, Pathname),
+           prefix: T.any(String, Pathname)).returns(T::Boolean)
+  }
+  def self.binary_linked_to_library?(binary, library, prefix = HOMEBREW_PREFIX)
+    Pathname.new(binary).dynamically_linked_libraries.any? do |dll|
+      next false unless dll.start_with?(prefix.to_s)
+
+      File.realpath(dll) == File.realpath(Pathname.new(library))
+    end
+  end
+end