tab: implement #reliable_runtime_dependencies?

Library/Homebrew/tab.rb

@@ -242,6 +242,26 @@ class Tab < OpenStruct
     super || DevelopmentTools.default_compiler
   end
 
+  def homebrew_tag
+    homebrew_version.sub(/\-\d+\-g([a-f0-9]+)(?:\-dirty)?\Z/, "")
+  end
+
+  def parsed_homebrew_version
+    return Version::NULL if homebrew_version.nil?
+    Version.new(homebrew_tag)
+  end
+
+  # Whether there is reliable runtime dependency information in the receipt.
+  def reliable_runtime_dependencies?
+    return false if runtime_dependencies.nil?
+
+    # Homebrew versions prior to 1.1.6 generated incorrect runtime dependency
+    # lists.
+    return false if parsed_homebrew_version < "1.1.6"
+
+    true
+  end
+
   def cxxstdlib
     # Older tabs won't have these values, so provide sensible defaults
     lib = stdlib.to_sym if stdlib

Library/Homebrew/test/tab_test.rb

@@ -69,6 +69,53 @@ class TabTests < Homebrew::TestCase
     assert_predicate tab, :universal?
   end
 
+  def test_homebrew_tag
+    tab = Tab.new(homebrew_version: "1.2.3")
+    assert_equal "1.2.3", tab.homebrew_tag
+
+    tab.homebrew_version = "1.2.4-567-g12789abdf"
+    assert_equal "1.2.4", tab.homebrew_tag
+
+    tab.homebrew_version = "2.0.0-134-gabcdefabc-dirty"
+    assert_equal "2.0.0", tab.homebrew_tag
+  end
+
+  def test_parsed_homebrew_version
+    tab = Tab.new
+    assert_same Version::NULL, tab.parsed_homebrew_version
+
+    tab = Tab.new(homebrew_version: "1.2.3")
+    assert_equal "1.2.3", tab.parsed_homebrew_version
+    assert_kind_of Version, tab.parsed_homebrew_version
+
+    tab = Tab.new(homebrew_version: "2.0.0-134-gabcdefabc-dirty")
+    assert_equal "2.0.0", tab.parsed_homebrew_version
+    assert_kind_of Version, tab.parsed_homebrew_version
+  end
+
+  def test_reliable_runtime_dependencies?
+    tab = Tab.new
+    refute_predicate tab, :reliable_runtime_dependencies?
+
+    tab.homebrew_version = "1.1.6"
+    refute_predicate tab, :reliable_runtime_dependencies?
+
+    tab.runtime_dependencies = []
+    assert_predicate tab, :reliable_runtime_dependencies?
+
+    tab.homebrew_version = "1.1.5"
+    refute_predicate tab, :reliable_runtime_dependencies?
+
+    tab.homebrew_version = "1.1.7"
+    assert_predicate tab, :reliable_runtime_dependencies?
+
+    tab.homebrew_version = "1.1.10"
+    assert_predicate tab, :reliable_runtime_dependencies?
+
+    tab.runtime_dependencies = [{ "full_name" => "foo", "version" => "1.0" }]
+    assert_predicate tab, :reliable_runtime_dependencies?
+  end
+
   def test_cxxstdlib
     assert_equal :clang, @tab.cxxstdlib.compiler
     assert_equal :libcxx, @tab.cxxstdlib.type