Content: Empty ref means default branch

Before we hard-coded main.
This lead to failure with old repos that used main as default branch

Author: schnatterer

docs/configuration.schema.json

@@ -187,7 +187,7 @@
               },
               "ref" : {
                 "type" : [ "string", "null" ],
-                "description" : "Reference for a specific branch, tag, or commit"
+                "description" : "Reference for a specific branch, tag, or commit. Emtpy defaults to default branch of the repo"
               },
               "target" : {
                 "type" : [ "string", "null" ],

src/main/groovy/com/cloudogu/gitops/config/Config.groovy

@@ -109,7 +109,7 @@ class Config {
             String path = '.'
 
             @JsonPropertyDescription(CONTENT_REPO_REF_DESCRIPTION)
-            String ref = 'main'
+            String ref = ''
 
             @JsonPropertyDescription(CONTENT_REPO_USERNAME_DESCRIPTION)
             String username = ''

src/main/groovy/com/cloudogu/gitops/config/ConfigConstants.groovy

@@ -33,7 +33,7 @@ interface ConfigConstants {
     String CONTENT_REPO_DESCRIPTION = "Content repos to push into target environment"
     String CONTENT_REPO_URL_DESCRIPTION = "URL of the content repo"
     String CONTENT_REPO_PATH_DESCRIPTION = "Path within the content repo to process"
-    String CONTENT_REPO_REF_DESCRIPTION = "Reference for a specific branch, tag, or commit"
+    String CONTENT_REPO_REF_DESCRIPTION = "Reference for a specific branch, tag, or commit. Emtpy defaults to default branch of the repo"
     String CONTENT_REPO_USERNAME_DESCRIPTION = "Username to authenticate against content repo"
     String CONTENT_REPO_PASSWORD_DESCRIPTION = "Password to authenticate against content repo"
     String CONTENT_REPO_TEMPLATING_DESCRIPTION = "When true, template all files ending in .ftl within the repo"

src/main/groovy/com/cloudogu/gitops/features/Content.groovy

@@ -17,7 +17,6 @@ import jakarta.inject.Singleton
 import org.apache.commons.io.FileUtils
 import org.eclipse.jgit.api.CloneCommand
 import org.eclipse.jgit.api.Git
-import org.eclipse.jgit.api.ResetCommand
 import org.eclipse.jgit.lib.Ref
 import org.eclipse.jgit.lib.Repository
 import org.eclipse.jgit.transport.UsernamePasswordCredentialsProvider
@@ -170,18 +169,18 @@ class Content extends Feature {
         def cloneCommand = gitClone()
                 .setURI(repo.url)
                 .setDirectory(repoTmpDir)
+                .setNoCheckout(false) // Checkout default branch
 
         if (repo.username != null && repo.password != null) {
             cloneCommand.setCredentialsProvider(
                     new UsernamePasswordCredentialsProvider(repo.username, repo.password))
         }
         def git = cloneCommand.call()
 
-        def actualRef = findRef(repo, git.repository)
-
-        // Avoid jgit removing and staging all files except .git which might lead to CheckoutConflictException during checkout
-        git.reset().setMode(ResetCommand.ResetType.HARD).call()
-        git.checkout().setName(actualRef).call()
+        if (repo.ref) {
+            def actualRef = findRef(repo, git.repository)
+            git.checkout().setName(actualRef).call()
+        }
     }
 
     private String findRef(Config.ContentSchema.ContentRepositorySchema repoConfig, Repository gitRepo) {

src/test/groovy/com/cloudogu/gitops/features/ContentTest.groovy

@@ -213,6 +213,18 @@ class ContentTest {
         assertThat(new File(findRoot(repos), "common/branch/README.md").text).contains("someBranch")
     }
 
+    @Test
+    void 'Checks out default branch when no ref set'() {
+        config.content.repos = [
+                new Config.ContentSchema.ContentRepositorySchema(url: createContentRepo('', 'git-repo-different-default-branch'), target: 'common/default'),
+        ]
+
+        def repos = createContent().cloneContentRepos()
+
+        assertThat(new File(findRoot(repos), "common/default/README.md")).exists().isFile()
+        assertThat(new File(findRoot(repos), "common/default/README.md").text).contains("different")
+    }
+
     @Test
     void 'Fails if commit refs does not exit'() {
         config.content.repos = [
@@ -489,35 +501,35 @@ class ContentTest {
     }
 
 
-    static String createContentRepo(String srcPath = '') {
+    static String createContentRepo(String initPath = '', String baseBareRepo = 'git-repository') {
         // The bare repo works as the "remote"
         def bareRepoDir = File.createTempDir('gitops-playground-test-content-repo')
         bareRepoDir.deleteOnExit()
         foldersToDelete << bareRepoDir
         // init with bare repo
-        FileUtils.copyDirectory(new File(System.getProperty("user.dir") + "/src/test/groovy/com/cloudogu/gitops/utils/data/git-repository/"), bareRepoDir)
+        FileUtils.copyDirectory(new File(System.getProperty("user.dir") + "/src/test/groovy/com/cloudogu/gitops/utils/data/${baseBareRepo}/"), bareRepoDir)
         def bareRepoUri = 'file://' + bareRepoDir.absolutePath
-        log.debug("Repo $srcPath: bare repo $bareRepoUri")
+        log.debug("Repo $initPath: bare repo $bareRepoUri")
 
-        if (srcPath) {
-            // Add srcPath to bare repo
+        if (initPath) {
+            // Add initPath to bare repo
             def tempRepo = File.createTempDir('gitops-playground-temp-repo')
             tempRepo.deleteOnExit()
             foldersToDelete << tempRepo
-            log.debug("Repo $srcPath: cloned bare repo to $tempRepo")
+            log.debug("Repo $initPath: cloned bare repo to $tempRepo")
             def git = Git.cloneRepository()
                     .setURI(bareRepoUri)
                     .setBranch('main')
                     .setDirectory(tempRepo)
                     .call()
 
-            FileUtils.copyDirectory(new File(System.getProperty("user.dir") + '/src/test/groovy/com/cloudogu/gitops/utils/data/contentRepos/' + srcPath), tempRepo)
+            FileUtils.copyDirectory(new File(System.getProperty("user.dir") + '/src/test/groovy/com/cloudogu/gitops/utils/data/contentRepos/' + initPath), tempRepo)
 
             git.add().addFilepattern(".").call()
 
             // Avoid complications with local developer's git config, e.g. when  git config --global commit.gpgSign true
             SystemReader.getInstance().userConfig.clear()
-            git.commit().setMessage("Initialize with $srcPath").call()
+            git.commit().setMessage("Initialize with $initPath").call()
             git.push().call()
             tempRepo.delete()
         }

src/test/groovy/com/cloudogu/gitops/utils/data/git-repo-different-default-branch/HEAD

@@ -0,0 +1 @@
+ref: refs/heads/different

src/test/groovy/com/cloudogu/gitops/utils/data/git-repo-different-default-branch/config

@@ -0,0 +1,4 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true

src/test/groovy/com/cloudogu/gitops/utils/data/git-repo-different-default-branch/description

@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.

src/test/groovy/com/cloudogu/gitops/utils/data/git-repo-different-default-branch/objects/23/cb5a712ce9ea3dc4770a350fc8ef5f51789d14

@@ -0,0 +1 @@
+x
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