Fix: consider version tag as actual version

Pre-releases weren't supported in Shards 0.8 and below, the only
solution was to use a tag to exactly match a pre-release.

Since a version is represented as a version tag in Shards, we can
safely report a version tag as the dependency version.

Author: ysbaddaden

src/dependency.cr

@@ -12,18 +12,23 @@ module Shards
       end
     end
 
-    def initialize(@name)
+    protected def initialize(@name)
       super()
     end
 
-    # DEPRECATED: with no replacement
-    def initialize(@name, config)
+    protected def initialize(@name, config)
       super()
       config.each { |k, v| self[k.to_s] = v.to_s }
     end
 
     def version
-      fetch("version", "*")
+      if version = self["version"]?
+        version
+      elsif self["tag"]? =~ VERSION_TAG
+        $1
+      else
+        "*"
+      end
     end
 
     def refs

test/dependency_test.cr

@@ -0,0 +1,29 @@
+require "./test_helper"
+
+class Shards::DependencyTest < Minitest::Test
+  def test_version
+    dependency = Dependency.new("app")
+    assert_equal "*", dependency.version
+
+    dependency = Dependency.new("app", {version: "*"})
+    assert_equal "*", dependency.version
+
+    dependency = Dependency.new("app", {version: "1.0.0"})
+    assert_equal "1.0.0", dependency.version
+
+    dependency = Dependency.new("app", {version: "<= 2.0.0"})
+    assert_equal "<= 2.0.0", dependency.version
+  end
+
+  def test_version_with_tags
+    dependency = Dependency.new("app", { tag: "fix/something" })
+    assert_equal "*", dependency.version
+
+    dependency = Dependency.new("app", { tag: "1.2.3" })
+    assert_equal "*", dependency.version
+
+    # version tag is considered a version:
+    dependency = Dependency.new("app", { tag: "v1.2.3-pre1" })
+    assert_equal "1.2.3-pre1", dependency.version
+  end
+end