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
+  [:needs_macos, :needs_linux].each do |needs_os|
+    describe "::binary_linked_to_library?", needs_os do
+      suffix = OS.mac? ? ".dylib" : ".so"
+
+      before do
+        mktmpdir do |dir|
+          (dir/"foo.h").write "void foo();"
+          (dir/"foo.c").write <<~C
+            #include <stdio.h>
+            #include "foo.h"
+            void foo() { printf("foo\\\\n"); }
+          C
+          (dir/"bar.c").write <<~C
+            #include <stdio.h>
+            void bar() { printf("bar\\\\n"); }
+          C
+          (dir/"test.c").write <<~C
+            #include "foo.h"
+            int main() { foo(); return 0; }
+          C
+
+          system "cc", "-c", "-fpic", dir/"foo.c", "-o", dir/"foo.o"
+          system "cc", "-c", "-fpic", dir/"bar.c", "-o", dir/"bar.o"
+          dll_flag = OS.mac? ? "-dynamiclib" : "-shared"
+          (HOMEBREW_PREFIX/"lib").mkdir
+          system "cc", dll_flag, "-o", HOMEBREW_PREFIX/"lib/libbrewfoo#{suffix}", dir/"foo.o"
+          system "cc", dll_flag, "-o", HOMEBREW_PREFIX/"lib/libbrewbar#{suffix}", dir/"bar.o"
+          rpath_flag = "-Wl,-rpath,#{HOMEBREW_PREFIX}/lib" if OS.linux?
+          system "cc", "-o", dir/"brewtest", dir/"test.c", *rpath_flag, "-L#{HOMEBREW_PREFIX/"lib"}", "-lbrewfoo"
+          (HOMEBREW_PREFIX/"bin").install dir/"brewtest"
+        end
+      end
+
+      it "returns true if the binary is linked to the library" do
+        result = described_class.binary_linked_to_library?(HOMEBREW_PREFIX/"bin/brewtest",
+                                                           HOMEBREW_PREFIX/"lib/libbrewfoo#{suffix}")
+        expect(result).to be true
+      end
+
+      it "returns false if the binary is not linked to the library" do
+        result = described_class.binary_linked_to_library?(HOMEBREW_PREFIX/"bin/brewtest",
+                                                           HOMEBREW_PREFIX/"lib/libbrewbar#{suffix}")
+        expect(result).to be false
+      end
+    end
+  end
+end

Library/Homebrew/utils/linkage.rb

@@ -0,0 +1,15 @@
+# typed: strict
+# frozen_string_literal: true
+
+module Utils
+  sig {
+    params(binary: T.any(String, Pathname), library: T.any(String, Pathname)).returns(T::Boolean)
+  }
+  def self.binary_linked_to_library?(binary, library)
+    Pathname.new(binary).dynamically_linked_libraries.any? do |dll|
+      next false unless dll.start_with?(HOMEBREW_PREFIX.to_s)
+
+      File.realpath(dll) == File.realpath(Pathname.new(library))
+    end
+  end
+end