Make embedded git.properties have lower priority than other git metadata sources

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/git/CILocalGitInfoBuilder.java

@@ -21,4 +21,9 @@ public GitInfo build(@Nullable String repositoryPath) {
     return new LocalFSGitInfoExtractor()
         .headCommit(Paths.get(repositoryPath, gitFolderName).toFile().getAbsolutePath());
   }
+
+  @Override
+  public int order() {
+    return 2;
+  }
 }

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/git/CIProviderGitInfoBuilder.java

@@ -16,4 +16,9 @@ public GitInfo build(@Nullable String repositoryPath) {
     CIProviderInfo ciProviderInfo = ciProviderInfoFactory.createCIProviderInfo(currentPath);
     return ciProviderInfo.buildCIGitInfo();
   }
+
+  @Override
+  public int order() {
+    return 1;
+  }
 }

internal-api/src/main/java/datadog/trace/api/git/EmbeddedGitInfoBuilder.java

@@ -67,4 +67,9 @@ public GitInfo build(@Nullable String repositoryPath) {
                 committerTime),
             gitProperties.getProperty("git.commit.message.full")));
   }
+
+  @Override
+  public int order() {
+    return Integer.MAX_VALUE;
+  }
 }

internal-api/src/main/java/datadog/trace/api/git/GitInfoBuilder.java

@@ -4,4 +4,6 @@
 
 public interface GitInfoBuilder {
   GitInfo build(@Nullable String repositoryPath);
+
+  int order();
 }

internal-api/src/main/java/datadog/trace/api/git/GitInfoProvider.java

@@ -4,9 +4,11 @@
 import datadog.trace.api.cache.DDCaches;
 import datadog.trace.util.Strings;
 import java.nio.file.Paths;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
@@ -21,7 +23,7 @@ public class GitInfoProvider {
     INSTANCE.registerGitInfoBuilder(new EmbeddedGitInfoBuilder());
   }
 
-  private final Collection<GitInfoBuilder> builders = new CopyOnWriteArrayList<>();
+  private volatile Collection<GitInfoBuilder> builders = Collections.emptyList();
 
   // in regular cases git info has to be built only once,
   // but there is a rare exception:
@@ -100,8 +102,11 @@ private static String firstNonBlankWithMatchingCommit(
     return null;
   }
 
-  public void registerGitInfoBuilder(GitInfoBuilder builder) {
-    builders.add(builder);
+  public synchronized void registerGitInfoBuilder(GitInfoBuilder builder) {
+    List<GitInfoBuilder> updatedBuilders = new ArrayList<>(builders);
+    updatedBuilders.add(builder);
+    updatedBuilders.sort(Comparator.comparingInt(GitInfoBuilder::order));
+    builders = updatedBuilders;
     gitInfoCache.clear();
   }
 }

internal-api/src/main/java/datadog/trace/api/git/UserSuppliedGitInfoBuilder.java

@@ -98,4 +98,9 @@ public GitInfo build(@Nullable String repositoryPath) {
 
     return gitInfo;
   }
+
+  @Override
+  public int order() {
+    return 0;
+  }
 }

internal-api/src/test/groovy/datadog/trace/api/git/GitInfoProviderTest.groovy

@@ -32,12 +32,13 @@ class GitInfoProviderTest extends Specification {
       )
 
     def gitInfoBuilderB = givenABuilderReturning(
-      new GitInfo(null, "branch", "tag", new CommitInfo("sha"))
+      new GitInfo(null, "branch", "tag", new CommitInfo("sha")), 2
       )
 
     def gitInfoProvider = new GitInfoProvider()
-    gitInfoProvider.registerGitInfoBuilder(gitInfoBuilderA)
+    // registering provider with higher order first, to check that the registration logic will do proper reordering after the second registration
     gitInfoProvider.registerGitInfoBuilder(gitInfoBuilderB)
+    gitInfoProvider.registerGitInfoBuilder(gitInfoBuilderA)
 
     when:
     def actualGitInfo = gitInfoProvider.getGitInfo(REPO_PATH)
@@ -238,8 +239,13 @@ class GitInfoProviderTest extends Specification {
   }
 
   private GitInfoBuilder givenABuilderReturning(GitInfo gitInfo) {
+    givenABuilderReturning(gitInfo, 1)
+  }
+
+  private GitInfoBuilder givenABuilderReturning(GitInfo gitInfo, int order) {
     def gitInfoBuilder = Stub(GitInfoBuilder)
     gitInfoBuilder.build(REPO_PATH) >> gitInfo
-    return gitInfoBuilder
+    gitInfoBuilder.order() >> order
+    gitInfoBuilder
   }
 }