Detect version mismatches between shard.yml and git tags

Author: RX14

spec/integration/install_spec.cr

@@ -376,6 +376,31 @@ describe "install" do
     end
   end
 
+  it "fails when shard.yml version doesn't match git tag" do
+    metadata = {
+      dependencies: {
+        version_mismatch: {git: git_url(:version_mismatch), version: "0.2.0"},
+      },
+    }
+    with_shard(metadata) do
+      ex = expect_raises(FailedCommand) { run "shards install --no-color" }
+      ex.stdout.should contain("Error shard version (0.1.0) doesn't match tag version (0.2.0)")
+      refute_installed "version_mismatch"
+    end
+  end
+
+  it "succeeds when version mismatch is fixed" do
+    metadata = {
+      dependencies: {
+        version_mismatch: {git: git_url(:version_mismatch), version: "0.2.1"},
+      },
+    }
+    with_shard(metadata) do
+      run "shards install"
+      assert_installed "version_mismatch", "0.2.1"
+    end
+  end
+
   it "test install old with version when shard was renamed" do
     metadata = {
       dependencies: {

spec/integration/spec_helper.cr

@@ -66,6 +66,11 @@ private def setup_repositories
   create_git_release "renamed", "0.2.0", "name: new_name\nversion: 0.2.0"
   create_git_version_commit "renamed", "0.3.0", "name: another_name\nversion: 0.3.0"
 
+  create_git_repository "version_mismatch"
+  create_git_release "version_mismatch", "0.1.0", "name: version_mismatch\nversion: 0.1.0"
+  create_git_release "version_mismatch", "0.2.0", "name: version_mismatch\nversion: 0.1.0"
+  create_git_release "version_mismatch", "0.2.1", "name: version_mismatch\nversion: 0.2.1"
+
   create_git_repository "inprogress"
   create_git_version_commit "inprogress", "0.1.0"
   create_git_version_commit "inprogress", "0.1.0"

src/molinillo_solver.cr

@@ -70,6 +70,9 @@ module Shards
           unless dependency.name == spec.name
             raise Error.new("Error shard name (#{spec.name}) doesn't match dependency name (#{dependency.name})")
           end
+          if spec.mismatched_version?
+            raise Error.new("Error shard version (#{spec.original_version}) doesn't match tag version (#{spec.version})")
+          end
         end
         resolver = spec.resolver || raise "BUG: returned Spec has no resolver"
         version = spec.version

src/resolvers/git.cr

@@ -42,7 +42,19 @@ module Shards
     end
 
     def spec(version = nil)
-      Spec.from_yaml(read_spec(version)).tap { |spec| spec.resolver = self }
+      spec = Spec.from_yaml(read_spec(version))
+      spec.resolver = self
+
+      if version && version =~ VERSION_REFERENCE
+        # In this case, we know that the version was looked up by git tag, so we
+        # validate the spec version against the tag version.
+        version = version.lstrip('v')
+        if spec.version != version
+          spec.mismatched_version = true
+        end
+      end
+
+      spec
     end
 
     private def spec?(version)

src/spec.cr

@@ -70,10 +70,12 @@ module Shards
 
     getter! name : String?
     getter! version : String?
+    getter! original_version : String?
     getter description : String?
     getter license : String?
     getter crystal : String?
     property resolver : Resolver?
+    property? mismatched_version = false
 
     # :nodoc:
     def initialize(pull : YAML::PullParser, validate = false)
@@ -84,7 +86,7 @@ module Shards
         when "name"
           @name = pull.read_scalar
         when "version"
-          @version = pull.read_scalar
+          @original_version = @version = pull.read_scalar
         when "description"
           @description = pull.read_scalar
         when "license"