Add support for the new GitLab raw url

In GitLab 12.0 the url changed from, e.g.:

https://gitlab.example.com/raw/example/example-dotnet-source-link/538b7a2b0d086146a6534bfe6f98a379191ea529/ExampleApplication/Program.cs

To:

https://gitlab.example.com/example/example-dotnet-source-link/-/raw/538b7a2b0d086146a6534bfe6f98a379191ea529/ExampleApplication/Program.cs

See https://gitlab.com/gitlab-org/gitlab/-/issues/28848
See #670

src/SourceLink.GitLab.UnitTests/GetSourceLinkUrlTests.cs

@@ -50,7 +50,31 @@ public void BuildSourceLinkUrl(string s1, string s2)
 
             bool result = task.Execute();
             AssertEx.AssertEqualToleratingWhitespaceDifferences("", engine.Log);
-            AssertEx.AreEqual("https://domain.com/x/y/a/b/raw/0123456789abcdefABCDEF000000000000000000/*", task.SourceLinkUrl);
+            AssertEx.AreEqual("https://domain.com/x/y/a/b/-/raw/0123456789abcdefABCDEF000000000000000000/*", task.SourceLinkUrl);
+            Assert.True(result);
+        }
+
+        [Theory]
+        [InlineData("", "/", "11.0")]
+        [InlineData("/", "", "11.0")]
+        [InlineData("/", "/", "11.0")]
+        public void BuildSourceLinkUrl_DeprecatedVersion(string s1, string s2, string version)
+        {
+            var engine = new MockEngine();
+
+            var task = new GetSourceLinkUrl()
+            {
+                BuildEngine = engine,
+                SourceRoot = new MockItem("/src/", KVP("RepositoryUrl", "http://subdomain.mygitlab.com:100/a/b" + s1), KVP("SourceControl", "git"), KVP("RevisionId", "0123456789abcdefABCDEF000000000000000000")),
+                Hosts = new[]
+                {
+                    new MockItem("mygitlab.com", KVP("ContentUrl", "https://domain.com/x/y" + s2), KVP("Version", version)),
+                }
+            };
+
+            bool result = task.Execute();
+            AssertEx.AssertEqualToleratingWhitespaceDifferences("", engine.Log);
+            AssertEx.AreEqual("https://domain.com/raw/x/y/a/b/0123456789abcdefABCDEF000000000000000000/*", task.SourceLinkUrl);
             Assert.True(result);
         }
     }

src/SourceLink.GitLab/GetSourceLinkUrl.cs

@@ -18,7 +18,34 @@ public sealed class GetSourceLinkUrl : GetSourceLinkUrlGitTask
         protected override string HostsItemGroupName => "SourceLinkGitLabHost";
         protected override string ProviderDisplayName => "GitLab";
 
+        private const string VersionMetadataName = "Version";
+
+        // see https://gitlab.com/gitlab-org/gitlab/-/issues/28848
+        // see https://gitlab.com/gitlab-org/gitlab-foss/-/blob/v14.1.2/config/routes/repository_deprecated.rb
+        private static readonly Version s_versionWithNewUrlFormat = new Version(12, 0);
+
         protected override string? BuildSourceLinkUrl(Uri contentUri, Uri gitUri, string relativeUrl, string revisionId, ITaskItem? hostItem)
-            => UriUtilities.Combine(UriUtilities.Combine(contentUri.ToString(), relativeUrl), "raw/" + revisionId + "/*");
+        {
+            var path = GetVersion(hostItem) >= s_versionWithNewUrlFormat
+                ? "-/raw/" + revisionId + "/*"
+                : "raw/" + revisionId + "/*";
+            return UriUtilities.Combine(UriUtilities.Combine(contentUri.ToString(), relativeUrl), path);
+        }
+
+        private Version GetVersion(ITaskItem? hostItem)
+        {
+            var versionAsString = hostItem?.GetMetadata(VersionMetadataName);
+            if (!NullableString.IsNullOrEmpty(versionAsString))
+            {
+                if (Version.TryParse(versionAsString, out var version))
+                {
+                    return version;
+                }
+
+                Log.LogError(CommonResources.ItemOfItemGroupMustSpecifyMetadata, hostItem!.ItemSpec, HostsItemGroupName, VersionMetadataName);
+            }
+
+            return s_versionWithNewUrlFormat;
+        }
     }
 }