test-bot: check all dependents for broken dylibs

Pulls 'brew linkage' in to main brew repo as a dev-cmd, and has test-bot
use it to detect dylib breakage, which usually means a revision bump is
needed. Checks all dependents, not just those with a 'test do' block
defined, since we can do this without formula support.

Closes #107.

Signed-off-by: Andrew Janke <andrew@apjanke.net>

Library/Homebrew/cmd/test-bot.rb

@@ -513,7 +513,8 @@ module Homebrew
       dependents -= @formulae
       dependents = dependents.map { |d| Formulary.factory(d) }
 
-      testable_dependents = dependents.select { |d| d.test_defined? && d.bottled? }
+      bottled_dependents = dependents.select { |d| d.bottled? }
+      testable_dependents = dependents.select { |d| d.bottled? && d.test_defined? }
 
       if (deps | reqs).any? { |d| d.name == "mercurial" && d.build? }
         run_as_not_developer { test "brew", "install", "mercurial" }
@@ -592,7 +593,7 @@ module Homebrew
         shared_test_args = ["--verbose"]
         shared_test_args << "--keep-tmp" if ARGV.keep_tmp?
         test "brew", "test", formula_name, *shared_test_args if formula.test_defined?
-        testable_dependents.each do |dependent|
+        bottled_dependents.each do |dependent|
           unless dependent.installed?
             test "brew", "fetch", "--retry", dependent.name
             next if steps.last.failed?
@@ -606,7 +607,10 @@ module Homebrew
             end
           end
           if dependent.installed?
-            test "brew", "test", "--verbose", dependent.name
+            test "brew", "linkage", "--test", dependent.name
+            if testable_dependents.include? dependent
+              test "brew", "test", "--verbose", dependent.name
+            end
           end
         end
         test "brew", "uninstall", "--force", formula_name

Library/Homebrew/dev-cmd/linkage.rb

@@ -0,0 +1,125 @@
+#
+# Description: check linkage of installed keg
+# Usage:
+#   brew linkage <formulae>
+#
+# Only works on installed formulae. An error is raised if it is run on uninstalled
+# formulae.
+#
+# Options:
+#  --test      - testing version: only display broken libs; exit non-zero if any
+#                breakage was found.
+
+require "set"
+require "keg"
+require "formula"
+
+module Homebrew
+
+  def linkage
+    found_broken_dylibs = false
+    ARGV.kegs.each do |keg|
+      ohai "Checking #{keg.name} linkage" if ARGV.kegs.size > 1
+      result = LinkageChecker.new(keg)
+      if ARGV.include?("--test")
+        result.display_test_output
+      else
+        result.display_normal_output
+      end
+      found_broken_dylibs = true if !result.broken_dylibs.empty?
+    end
+    if ARGV.include?("--test") && found_broken_dylibs
+      exit 1
+    end
+  end
+
+  class LinkageChecker
+    attr_reader :keg
+    attr_reader :broken_dylibs
+
+    def initialize(keg)
+      @keg = keg
+      @brewed_dylibs = Hash.new { |h, k| h[k] = Set.new }
+      @system_dylibs = Set.new
+      @broken_dylibs = Set.new
+      @variable_dylibs = Set.new
+      check_dylibs
+    end
+
+    def check_dylibs
+      @keg.find do |file|
+        next unless file.dylib? || file.mach_o_executable? || file.mach_o_bundle?
+        file.dynamically_linked_libraries.each do |dylib|
+          if dylib.start_with? "@"
+            @variable_dylibs << dylib
+          else
+            begin
+              owner = Keg.for Pathname.new(dylib)
+            rescue NotAKegError
+              @system_dylibs << dylib
+            rescue Errno::ENOENT
+              @broken_dylibs << dylib
+            else
+              @brewed_dylibs[owner.name] << dylib
+            end
+          end
+        end
+      end
+
+      begin
+        f = Formula[keg.name]
+        @undeclared_deps = @brewed_dylibs.keys - f.deps.map(&:name)
+        @undeclared_deps -= [f.name]
+      rescue FormulaUnavailableError
+        opoo "Formula unavailable: #{keg.name}"
+        @undeclared_deps = []
+      end
+
+    end
+
+    def display_normal_output
+      unless @system_dylibs.empty?
+        display_items "System libraries", @system_dylibs
+      end
+      unless @brewed_dylibs.empty?
+        display_items "Homebrew libraries", @brewed_dylibs
+      end
+      unless @variable_dylibs.empty?
+        display_items "Variable-referenced libraries", @variable_dylibs
+      end
+      unless @broken_dylibs.empty?
+        display_items "Missing libraries", @broken_dylibs
+      end
+      unless @undeclared_deps.empty?
+        display_items "Possible undeclared dependencies", @undeclared_deps
+      end
+    end
+
+    def display_test_output
+      if @broken_dylibs.empty?
+        puts "No broken dylib links"
+      else
+        display_items "Missing libraries", @broken_dylibs
+      end
+    end
+
+    private
+
+    # Display a list of things.
+    # Things may either be an array, or a hash of (label -> array)
+    def display_items(label, things)
+      puts "#{label}:"
+      if things.is_a? Hash
+        things.sort.each do |label, list|
+          list.sort.each do |item|
+            puts "  #{item} (#{label})"
+          end
+        end
+      else
+        things.sort.each do |item|
+          puts "  #{item}"
+        end
+      end
+    end
+  end
+end