Improve tokenization of version strings

Tokens like "b4", "beta1", "p195", &c. are now treated as atoms rather
than being broken down even further. Additionally, we enable support for
padding in the middle of versions strings, so we can successfully
compare something like "2.1-p195" with "2.1.0-p194" by inferring that
"2.1" is really "2.1.0".

This fixes the comparison "9.9.3-P1" > "9.9.3" which previously has not
been handled correctly.

Library/Homebrew/test/test_versions.rb

@@ -8,10 +8,20 @@ class VersionComparisonTests < Test::Unit::TestCase
     assert_operator version('0.1'), :==, version('0.1.0')
     assert_operator version('0.1'), :<, version('0.2')
     assert_operator version('1.2.3'), :>, version('1.2.2')
-    assert_operator version('1.2.3-p34'), :>, version('1.2.3-p33')
     assert_operator version('1.2.4'), :<, version('1.2.4.1')
+  end
+
+  def test_patchlevel
+    assert_operator version('1.2.3-p34'), :>, version('1.2.3-p33')
+    assert_operator version('1.2.3-p33'), :<, version('1.2.3-p34')
+  end
+
+  def test_HEAD
     assert_operator version('HEAD'), :>, version('1.2.3')
     assert_operator version('1.2.3'), :<, version('HEAD')
+  end
+
+  def test_alpha_beta_rc
     assert_operator version('3.2.0b4'), :<, version('3.2.0')
     assert_operator version('1.0beta6'), :<, version('1.0b7')
     assert_operator version('1.0b6'), :<, version('1.0beta7')
@@ -19,13 +29,18 @@ class VersionComparisonTests < Test::Unit::TestCase
     assert_operator version('1.1beta2'), :<, version('1.1rc1')
     assert_operator version('1.0.0beta7'), :<, version('1.0.0')
     assert_operator version('3.2.1'), :>, version('3.2beta4')
-    assert_nil version('1.0') <=> 'foo'
   end
 
-  def test_version_queries
+  def test_comparing_unevenly_padded_versions
-    assert Version.new("1.1alpha1").alpha?
+    assert_operator version('2.1.0-p194'), :<, version('2.1-p195')
-    assert Version.new("1.0beta2").beta?
+    assert_operator version('2.1-p195'), :>, version('2.1.0-p194')
-    assert Version.new("1.0rc-1").rc?
+    assert_operator version('2.1-p194'), :<, version('2.1.0-p195')
+    assert_operator version('2.1.0-p195'), :>, version('2.1-p194')
+    assert_operator version('2-p194'), :<, version('2.1-p195')
+  end
+
+  def test_comparison_returns_nil_for_non_version
+    assert_nil version('1.0') <=> 'foo'
   end
 
   def test_compare_patchlevel_to_non_patchlevel

Library/Homebrew/version.rb

@@ -1,46 +1,148 @@
-class VersionElement
-  include Comparable
-
-  def initialize elem
-    elem = elem.to_s.downcase
-    @elem = case elem
-      when /\d+/ then elem.to_i
-      when 'a', 'alpha' then 'alpha'
-      when 'b', 'beta' then 'beta'
-      else elem
-      end
-  end
-
-  ZERO = VersionElement.new(0)
-
-  def <=>(other)
-    return unless other.is_a? VersionElement
-    return -1 if string? and other.numeric?
-    return 1 if numeric? and other.string?
-    return elem <=> other.elem
-  end
-
-  def to_s
-    @elem.to_s
-  end
-
-  protected
-
-  attr_reader :elem
-
-  def string?
-    elem.is_a? String
-  end
-
-  def numeric?
-    elem.is_a? Numeric
-  end
-end
-
 class Version
   include Comparable
 
-  def initialize val, detected=false
+  class Token
+    include Comparable
+
+    attr_reader :value
+
+    def initialize(value)
+      @value = value
+    end
+
+    def inspect
+      "#<#{self.class} #{value.inspect}>"
+    end
+  end
+
+  class NullToken < Token
+    def initialize(value=nil)
+      super
+    end
+
+    def <=>(other)
+      case other
+      when NumericToken
+        other.value == 0 ? 0 : -1
+      when AlphaToken, BetaToken, RCToken
+        1
+      else
+        -1
+      end
+    end
+
+    def inspect
+      "#<#{self.class}>"
+    end
+  end
+
+  NULL_TOKEN = NullToken.new
+
+  class StringToken < Token
+    PATTERN = /[a-z]+[0-9]+/i
+
+    def initialize(value)
+      @value = value.to_s
+    end
+
+    def <=>(other)
+      case other
+      when StringToken
+        value <=> other.value
+      when NumericToken, NullToken
+        -Integer(other <=> self)
+      end
+    end
+  end
+
+  class NumericToken < Token
+    PATTERN = /[0-9]+/i
+
+    def initialize(value)
+      @value = value.to_i
+    end
+
+    def <=>(other)
+      case other
+      when NumericToken
+        value <=> other.value
+      when StringToken
+        1
+      when NullToken
+        -Integer(other <=> self)
+      end
+    end
+  end
+
+  class CompositeToken < StringToken
+    def rev
+      value[/([0-9]+)/, 1]
+    end
+  end
+
+  class AlphaToken < CompositeToken
+    PATTERN = /a(?:lpha)?[0-9]+/i
+
+    def <=>(other)
+      case other
+      when AlphaToken
+        rev <=> other.rev
+      else
+        super
+      end
+    end
+  end
+
+  class BetaToken < CompositeToken
+    PATTERN = /b(?:eta)?[0-9]+/i
+
+    def <=>(other)
+      case other
+      when BetaToken
+        rev <=> other.rev
+      when AlphaToken
+        1
+      when RCToken, PatchToken
+        -1
+      else
+        super
+      end
+    end
+  end
+
+  class RCToken < CompositeToken
+    PATTERN = /rc[0-9]+/i
+
+    def <=>(other)
+      case other
+      when RCToken
+        rev <=> other.rev
+      when AlphaToken, BetaToken
+        1
+      when PatchToken
+        -1
+      else
+        super
+      end
+    end
+  end
+
+  class PatchToken < CompositeToken
+    PATTERN = /p[0-9]+/i
+
+    def <=>(other)
+      case other
+      when PatchToken
+        rev <=> other.rev
+      when AlphaToken, BetaToken, RCToken
+        1
+      else
+        super
+      end
+    end
+  end
+
+  def initialize(val, detected=false)
     @version = val.to_s
     @detected_from_url = detected
   end
@@ -53,40 +155,14 @@ class Version
     @version == 'HEAD'
   end
 
-  def devel?
-    alpha? or beta? or rc?
-  end
-
-  def alpha?
-    to_a.any? { |e| e.to_s == 'alpha' }
-  end
-
-  def beta?
-    to_a.any? { |e| e.to_s == 'beta' }
-  end
-
-  def rc?
-    to_a.any? { |e| e.to_s == 'rc' }
-  end
-
   def <=>(other)
-    # Return nil if objects aren't comparable
+    return unless Version === other
-    return unless other.is_a? Version
+    return 0 if head? && other.head?
-    # Versions are equal if both are HEAD
+    return 1 if head? && !other.head?
-    return  0 if head? and other.head?
+    return -1 if !head? && other.head?
-    # HEAD is greater than any numerical version
-    return  1 if head? and not other.head?
-    return -1 if not head? and other.head?
 
-    stuple, otuple = to_a, other.to_a
+    max = [tokens.length, other.tokens.length].max
-    slen, olen = stuple.length, otuple.length
+    pad_to(max) <=> other.pad_to(max)
-
-    max = [slen, olen].max
-
-    stuple.fill(VersionElement::ZERO, slen, max - slen)
-    otuple.fill(VersionElement::ZERO, olen, max - olen)
-
-    stuple <=> otuple
   end
 
   def to_s
@@ -96,8 +172,36 @@ class Version
 
   protected
 
-  def to_a
+  def pad_to(length)
-    @array ||= @version.scan(/\d+|[a-zA-Z]+/).map! { |e| VersionElement.new(e) }
+    nums, rest = tokens.partition { |t| NumericToken === t }
+    nums.concat([NULL_TOKEN]*(length - tokens.length)).concat(rest)
+  end
+
+  def tokens
+    @tokens ||= tokenize
+  end
+  alias_method :to_a, :tokens
+
+  def tokenize
+    @version.scan(
+      Regexp.union(
+        AlphaToken::PATTERN,
+        BetaToken::PATTERN,
+        RCToken::PATTERN,
+        PatchToken::PATTERN,
+        NumericToken::PATTERN,
+        StringToken::PATTERN
+      )
+    ).map! do |token|
+      case token
+      when /\A#{AlphaToken::PATTERN}\z/o   then AlphaToken
+      when /\A#{BetaToken::PATTERN}\z/o    then BetaToken
+      when /\A#{RCToken::PATTERN}\z/o      then RCToken
+      when /\A#{PatchToken::PATTERN}\z/o   then PatchToken
+      when /\A#{NumericToken::PATTERN}\z/o then NumericToken
+      when /\A#{StringToken::PATTERN}\z/o  then StringToken
+      end.new(token)
+    end
   end
 
   def self.parse spec