For CI - automatic semver calculation for Gradle project.

.travis.yml

@@ -248,10 +248,10 @@ before_script:
   - export TRAVIS_COMMIT=$TRAVIS_COMMIT~
   - export COMMIT_MESSAGE=$(git log --format=%B -n1 $TRAVIS_COMMIT)
   - export TAG=$(git describe --exact-match $TRAVIS_COMMIT 2>/dev/null); if [[ $TAG =~ [[:digit:]]+\.[[:digit:]]+ ]]; then export RELEASE_TAG=$TAG; fi
-  - if [[ $RELEASE_TAG ]] || (! [[ $TRAVIS_BRANCH =~ [^-]+-[^-]+-CI ]] && echo $COMMIT_MESSAGE |grep -cq '\[ci package\]'); then export PACKAGE_UPLOAD=1; fi
+  - if [[ $RELEASE_TAG ]] || (! [[ $TRAVIS_BRANCH =~ [^-]+-[^-]+-CI ]] && echo $COMMIT_MESSAGE |grep -cq '\[ci package\]'); then export bintrayUpload=bintrayUpload; fi
   - if [[ "$ORG_GRADLE_PROJECT_URHO3D_LIB_TYPE" == "STATIC" ]]; then export ORG_GRADLE_PROJECT_URHO3D_SAMPLES=0; fi
   - rake ci_setup_cache
-script: script/dockerized.sh android ./gradlew build bintrayUpload --console plain && if [[ $PACKAGE_UPLOAD ]]; then script/dockerized.sh android rake ci_package_upload; fi && rake ci_timer
+script: script/dockerized.sh android ./gradlew build $bintrayUpload --console plain && rake ci_timer
 matrix:
   fast_finish: true
   include: [stage: housekeep]

build.gradle.kts

@@ -20,6 +20,9 @@
 // THE SOFTWARE.
 //
 
+import org.gradle.internal.io.NullOutputStream
+import java.io.ByteArrayOutputStream
+
 plugins {
     base
     // For some reasons the lint task requires bintray plugin to be declared here too in order to work as expected
@@ -28,13 +31,45 @@ plugins {
 
 allprojects {
     group = "com.github.urho3d"
-    version = "1.8-BETA"
+    version = determineVersion()
     description = """Urho3D is a free lightweight,
                     |cross-platform 2D and 3D game engine implemented in C++ and released under the MIT license.
-                    |Greatly inspired by OGRE and Horde3D."""
-            .trimMargin().replace('\n', ' ')
+                    |Greatly inspired by OGRE and Horde3D.""".trimMargin().replace('\n', ' ')
     repositories {
         google()
         jcenter()
     }
 }
+
+/**
+ * Find the most recent tag that is reachable from a commit and use that to set the Gradle's project version.
+ *
+ * e.g. commit described as "1.7-664-g34b1" will be mapped to "1.8-BETA" (rolling release for the next version)
+ *      tag "1.8" will be mapped to "1.8" as is (point release version), so does tag "1.8-RC" (release candidate)
+ */
+fun determineVersion(): String {
+    // If it is explicitly specified then let return it instead
+    System.getenv("GRADLE_PROJECT_VERSION")?.let { return it }
+    val desc = describeCommit(System.getenv("TRAVIS_COMMIT") ?: System.getenv("APPVEYOR_REPO_COMMIT"))
+    return Regex("^(.+?)-\\d").find(desc)?.destructured?.component1()?.let { "${bumpSemVer(it, 1)}-BETA" } ?: desc
+}
+
+/**
+ * Find the most recent tag that is reachable from a commit.
+ */
+fun describeCommit(sha: String? = null) = ByteArrayOutputStream().also {
+    exec {
+        commandLine = listOf("git", "describe", "--tags", sha ?: "--dirty")
+        standardOutput = it
+        errorOutput = NullOutputStream.INSTANCE
+        isIgnoreExitValue = true    // In case no GIT command line tool or not a GIT repository
+    }
+}.toString().trim().let { if (it.isBlank()) "Unversioned" else it }
+
+/**
+ * Bump the semantic versioning on the specified index, 0 for major version, 1 for minor version, and so on.
+ */
+fun bumpSemVer(version: String, index: Int) = version
+        .split('.')
+        .mapIndexed { i: Int, s: String -> if (i == index) (s.toInt() + 1).toString() else s }
+        .joinToString(".")