Version matcher now prefers a specific match over a partial match (#907)

Previous to this commit, if you have two versions say `3.1.1` and `3.1.1_BETA` the version matcher would incorrectly select `3.1.1_BETA`.  It would behave as if a wildcard was present even though it's not present.

This commit ensures that the same scenario will select version `3.1.1`, which is an exact match for the version requested.

This may result in a difference of behavior for some users. If you are impacted by this, you need to switch your requested version to `3.1.1_+`. Using the scenario above, this will return `3.1.1_BETA`.

Signed-off-by: Daniel Mikusa <dmikusa@vmware.com>

Author: Daniel Mikusa

lib/java_buildpack/repository/version_resolver.rb

@@ -76,18 +76,25 @@ def safe_candidate_version(candidate_version)
         end
 
         def matches?(tokenized_candidate_version, tokenized_version)
+          wildcard_matched = false
           (0..3).all? do |i|
-            tokenized_candidate_version[i].nil? || as_regex(tokenized_candidate_version[i]) =~ tokenized_version[i]
-          end
-        end
+            next true if wildcard_matched || tokenized_candidate_version[i].nil? && tokenized_version[i].nil?
 
-        def as_regex(version)
-          /^#{version.gsub(JavaBuildpack::Util::TokenizedVersion::WILDCARD, '.*')}/
-        end
+            next false if tokenized_candidate_version[i].nil? && !tokenized_version[i].nil?
 
-      end
+            if tokenized_candidate_version[i] == JavaBuildpack::Util::TokenizedVersion::WILDCARD
+              wildcard_matched = true
+              next true
+            end
 
-    end
+            if tokenized_candidate_version[i].end_with?(JavaBuildpack::Util::TokenizedVersion::WILDCARD)
+              next !tokenized_version[i].nil? && tokenized_version[i].start_with?(tokenized_candidate_version[i][0..-2])
+            end
 
+            tokenized_candidate_version[i] == tokenized_version[i]
+          end
+        end
+      end
+    end
   end
 end

spec/java_buildpack/repository/version_resolver_spec.rb

@@ -69,6 +69,18 @@
     expect(described_class.resolve(tokenized_version('2.0.+'), versions)).to eq(tokenized_version('2.0.0'))
   end
 
+  it 'picks an exact match over a partial match' do
+    versions = %w[3.1.1 3.1.1_BETA 3.1.1_BETA.2 3.1.2 3.2.0]
+    expect(described_class.resolve(tokenized_version('3.1.1'), versions)).to eq(tokenized_version('3.1.1'))
+    expect(described_class.resolve(tokenized_version('3.1.1_BETA'), versions)).to eq(tokenized_version('3.1.1_BETA'))
+  end
+
+  it 'picks the latest including qualifiers' do
+    versions = %w[3.1.1 3.1.1_BETA 3.1.1_BETA.2 3.1.2 3.2.0]
+    expect(described_class.resolve(tokenized_version('3.1.1_+'), versions)).to eq(tokenized_version('3.1.1_BETA.2'))
+    expect(described_class.resolve(tokenized_version('3.1.1_BE+'), versions)).to eq(tokenized_version('3.1.1_BETA.2'))
+  end
+
   def tokenized_version(s)
     JavaBuildpack::Util::TokenizedVersion.new(s)
   end