add functionality to search parent dirs for git repo

Author: jmcampanini

.gitignore

@@ -1,4 +1,5 @@
 build
+out/
 bin
 *.class
 
@@ -8,6 +9,7 @@ bin
 .checkstyle
 .settings
 .node
+*.iml
 *.ipr
 *.iws
 .idea

src/main/groovy/com/palantir/gradle/gitversion/GitVersionPlugin.groovy

@@ -27,7 +27,7 @@ class GitVersionPlugin implements Plugin<Project> {
 
     void apply(Project project) {
         project.ext.gitVersion = {
-            File gitDir = new File(project.rootDir, '.git')
+            File gitDir = findRootGitDir(project.rootDir)
             if (!gitDir.exists()) {
                 throw new IllegalArgumentException('Cannot find \'.git\' directory')
             }
@@ -46,5 +46,20 @@ class GitVersionPlugin implements Plugin<Project> {
             println project.version
         }
     }
-}
 
+    private File findRootGitDir(File currentRoot) {
+        File gitDir = new File(currentRoot, '.git')
+
+        if (gitDir.exists()) {
+            return gitDir
+        }
+
+        // stop at the root directory, return non-existing File object
+        if (currentRoot.parentFile == null) {
+            return gitDir
+        }
+
+        // look in parent directory
+        return findRootGitDir(currentRoot.parentFile)
+    }
+}

src/test/groovy/com/palantir/gradle/gitversion/GitVersionPluginTests.groovy

@@ -52,6 +52,31 @@ class GitVersionPluginTests extends Specification {
         buildResult.output.contains('> Cannot find \'.git\' directory')
     }
 
+    def 'git describe works when git repo is multiple levels up' () {
+        given:
+        File rootFolder = temporaryFolder.root
+        projectDir = temporaryFolder.newFolder('level1', 'level2')
+        buildFile = temporaryFolder.newFile('level1/level2/build.gradle')
+        buildFile << '''
+            plugins {
+                id 'com.palantir.git-version'
+            }
+            version gitVersion()
+        '''.stripIndent()
+        gitIgnoreFile << 'build'
+        Git git = Git.init().setDirectory(rootFolder).call();
+        git.add().addFilepattern('.').call()
+        git.commit().setMessage('initial commit').call()
+        git.tag().setAnnotated(true).setMessage('1.0.0').setName('1.0.0').call()
+
+        when:
+        // will build the project at projectDir
+        BuildResult buildResult = with('printVersion').build()
+
+        then:
+        buildResult.output.contains(":printVersion\n1.0.0\n")
+    }
+
     def 'unspecified when no tags are present' () {
         given:
         buildFile << '''