Do not try to fail .git folder provider, fail at runtime if it's not available (#14951)

* Fix early resolution of git dir property which may not be available for source bundles.

* Fail at runtime if .git is not available. environment doesn't support providers.

* Don't return anything from dotgit provider if .git cannot be located.

* Add a comment.

Author: dweiss

build-tools/build-infra/src/main/java/org/apache/lucene/gradle/plugins/gitinfo/GitInfoPlugin.java

@@ -53,9 +53,9 @@ public void apply(Project project) {
                           project.getRootProject().getLayout().getProjectDirectory();
                       Path gitLocation = projectDirectory.getAsFile().toPath().resolve(".git");
                       if (!Files.exists(gitLocation)) {
-                        throw new GradleException(
-                            "Can't locate .git (probably not a git clone?): "
-                                + gitLocation.toAbsolutePath());
+                        // don't return anything from the provider if we can't locate the .git
+                        // folder. This will result in the property returning false from isPresent.
+                        return null;
                       }
 
                       if (Files.isDirectory(gitLocation)) {

lucene/distribution/build.gradle

@@ -53,7 +53,13 @@ tasks.register("assembleSourceTgz", QuietExec, {
   workingDir = project.rootDir
 
   // An explicit GIT_DIR to prevent .git upward scanning if something goes wrong.
-  environment("GIT_DIR", "${gitInfoExt.getDotGitDir().get().asFile.toString()}")
+  if (gitInfoExt.getDotGitDir().isPresent()) {
+    environment("GIT_DIR", gitInfoExt.getDotGitDir().get().asFile.toString())
+  } else {
+    doFirst {
+      throw new GradleException("Can't assemble source tgz without a full git clone.")
+    }
+  }
 
   args += [
       "archive",