Formula: ignore_missing_libraries DSL

Library/Homebrew/extend/os/linux/formula.rb

@@ -7,11 +7,37 @@ class Formula
     "#{name}.so#{"." unless version.nil?}#{version}"
   end
 
+  undef allowed_missing_lib?
+  def allowed_missing_lib?(lib)
+    # lib:   Full path to the missing library
+    #        Ex.: /home/linuxbrew/.linuxbrew/lib/libsomething.so.1
+    # x -    Name of or a pattern for a library, linkage to which is allowed to be missing.
+    #        Ex. 1: "libONE.so.1"
+    #        Ex. 2: %r{(libONE|libTWO)\.so}
+    self.class.allowed_missing_libraries.any? do |x|
+      if x.is_a? Regexp
+        x.match? lib
+      elsif x.is_a? String
+        lib.include? x
+      end
+    end
+  end
+
   class << self
     undef on_linux
 
     def on_linux(&_block)
       yield
     end
+
+    def ignore_missing_libraries(*libs)
+      libs.flatten!
+      allowed_missing_libraries.merge(libs)
+    end
+
+    # @private
+    def allowed_missing_libraries
+      @allowed_missing_libraries ||= Set.new
+    end
   end
 end

Library/Homebrew/formula.rb

@@ -1131,10 +1131,10 @@ class Formula
     end
   end
 
-  # Whether this {Formula} is allowed to have broken linkage.
+  # Whether this {Formula} is allowed to have a broken linkage to specified library.
   # Defaults to false.
   # @return [Boolean]
-  def allow_missing_libs?
+  def allowed_missing_lib?(*)
     false
   end
 
@@ -2603,10 +2603,6 @@ class Formula
       @skip_clean_paths ||= Set.new
     end
 
-    def allow_missing_libs
-      define_method(:allow_missing_libs?) { true }
-    end
-
     # Software that will not be symlinked into the `brew --prefix` will only
     # live in its Cellar. Other formulae can depend on it and then brew will
     # add the necessary includes and libs (etc.) during the brewing of that

Library/Homebrew/linkage_checker.rb

@@ -55,24 +55,35 @@ class LinkageChecker
   end
 
   def display_test_output(puts_output: true)
-    display_items "Missing libraries", @broken_dylibs, puts_output: puts_output
+    display_items "Missing libraries", broken_dylibs_with_expectations, puts_output: puts_output
     display_items "Broken dependencies", @broken_deps, puts_output: puts_output
     display_items "Unwanted system libraries", @unwanted_system_dylibs, puts_output: puts_output
     display_items "Conflicting libraries", @version_conflict_deps, puts_output: puts_output
-    if got_library_issues?
+
-      puts "Broken library linkage ignored" if @formula.allow_missing_libs?
+    if @broken_dylibs.empty?
+      puts "No broken library linkage detected"
+    elsif unexpected_broken_libs.empty?
+      puts "No unexpected broken library linkage detected."
     else
-      puts "No broken library linkage"
+      puts "Broken library linkage detected"
     end
   end
 
   def broken_library_linkage?
-    !@formula.allow_missing_libs? && got_library_issues?
+    issues = [@broken_deps, @unwanted_system_dylibs, @version_conflict_deps]
+    [issues, unexpected_broken_libs].flatten.any?(&:present?)
   end
 
-  def got_library_issues?
+  def unexpected_broken_libs
-    issues = [@broken_dylibs, @broken_deps, @unwanted_system_dylibs, @version_conflict_deps]
+    @broken_dylibs.reject { |lib| @formula.allowed_missing_lib? lib }
-    issues.any?(&:present?)
+  end
+
+  def broken_dylibs_with_expectations
+    output = {}
+    @broken_dylibs.each do |lib|
+      output[lib] = (unexpected_broken_libs.include? lib) ? ["unexpected"] : ["expected"]
+    end
+    output
   end
 
   private