Introduce Gradle, Errorprone, Spotless and GitHub Actions

This change introduces build and CI toolchain. The package name is
still experimental, will be decided in #1.

close #54

.gitattributes

@@ -0,0 +1,2 @@
+gradlew linguist-generated=true
+gradlew.bat linguist-generated=true

.github/workflows/build.yml

@@ -0,0 +1,21 @@
+name: Build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11 # to use compile-time analysis by Errorprone
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - uses: actions/cache@v1
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - run: |
+          ./gradlew spotlessCheck build --no-daemon

.gitignore

@@ -0,0 +1,174 @@
+
+# Created by https://www.gitignore.io/api/gradle,eclipse,intellij
+# Edit at https://www.gitignore.io/?templates=gradle,eclipse,intellij
+
+### Eclipse ###
+.metadata
+bin/
+tmp/
+*.tmp
+*.bak
+*.swp
+*~.nib
+local.properties
+.settings/
+.loadpath
+.recommenders
+
+# External tool builders
+.externalToolBuilders/
+
+# Locally stored "Eclipse launch configurations"
+*.launch
+
+# PyDev specific (Python IDE for Eclipse)
+*.pydevproject
+
+# CDT-specific (C/C++ Development Tooling)
+.cproject
+
+# CDT- autotools
+.autotools
+
+# Java annotation processor (APT)
+.factorypath
+
+# PDT-specific (PHP Development Tools)
+.buildpath
+
+# sbteclipse plugin
+.target
+
+# Tern plugin
+.tern-project
+
+# TeXlipse plugin
+.texlipse
+
+# STS (Spring Tool Suite)
+.springBeans
+
+# Code Recommenders
+.recommenders/
+
+# Annotation Processing
+.apt_generated/
+
+# Scala IDE specific (Scala & Java development for Eclipse)
+.cache-main
+.scala_dependencies
+.worksheet
+
+### Eclipse Patch ###
+# Eclipse Core
+.project
+
+# JDT-specific (Eclipse Java Development Tools)
+.classpath
+
+# Annotation Processing
+.apt_generated
+
+.sts4-cache/
+
+### Intellij ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Intellij Patch ###
+# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+
+# *.iml
+# modules.xml
+# .idea/misc.xml
+# *.ipr
+
+# Sonarlint plugin
+.idea/sonarlint
+
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+### Gradle Patch ###
+**/build/
+
+# End of https://www.gitignore.io/api/gradle,eclipse,intellij

AUTHORS

@@ -1,6 +1,7 @@
 # This is the list of jspecify authors for copyright purposes.
 #
 # This does not necessarily list everyone who has contributed code, since in
-# some cases, their employer may be the copyright holder.  To see the full list
+# some cases, their employer may be the copyright holder. To see the full list
 # of contributors, see the revision history in source control.
 Google LLC
+SpotBugs Team

README.md

@@ -7,3 +7,8 @@ Our focus during 2018-2021 is annotations for nullness.
 
 This is not an officially supported product of any of the participant
 organizations.
+
+## How to build
+
+Simply run `./gradlew` to build artifacts.
+Or run `./gradlew publishToMavenLocal` to install artifacts to your Local Maven Repository.

build.gradle

@@ -0,0 +1,29 @@
+plugins {
+    id 'java-library'
+    id 'maven-publish'
+    id 'com.diffplug.gradle.spotless' version '3.28.1'
+    id 'net.ltgt.errorprone' version '1.1.1'
+}
+
+apply from: "$rootDir/gradle/format.gradle"
+apply from: "$rootDir/gradle/publish.gradle"
+
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
+
+repositories { mavenCentral() }
+
+ext {
+    junitVersion = '5.6.1'
+    errorproneVersion = '2.3.4'
+}
+
+dependencies {
+    testImplementation "org.junit.jupiter:junit-jupiter-api:${junitVersion}"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${junitVersion}"
+    errorprone "com.google.errorprone:error_prone_core:${errorproneVersion}"
+}
+
+test { useJUnitPlatform() }
+
+defaultTasks 'spotlessApply', 'build'

gradle.properties

@@ -0,0 +1 @@
+version = 0.1.0-SNAPSHOT

gradle/format.gradle

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+spotless {
+    java {
+        removeUnusedImports()
+        googleJavaFormat()
+        licenseHeaderFile "$rootDir/gradle/license-header.java"
+    }
+    groovyGradle {
+        target '**/*.gradle'
+        greclipse()
+        indentWithSpaces()
+        paddedCell()
+    }
+}

gradle/license-header.java

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2018-2020 The jspecify Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */

gradle/publish.gradle

@@ -0,0 +1,26 @@
+// run `./gradlew publishToMavenLocal` to install artifact to your Local Maven Repository
+
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            pom {
+                groupId = 'org.jspecify.experimentaldonotuse'
+                name = 'jspecify'
+                description = 'An artifact of well-named and well-specified annotations to power static analysis checks'
+                url = 'https://jspecify.org/'
+                from components.java
+                licenses {
+                    license {
+                        name = 'The Apache License, Version 2.0'
+                        url = 'http://www.apache.org/licenses/LICENSE-2.0.txt'
+                    }
+                }
+                scm {
+                    connection = 'scm:git:git@github.com:jspecify/jspecify.git'
+                    developerConnection = 'scm:git:git@github.com:jspecify/jspecify.git'
+                    url = 'https://github.com/jspecify/jspecify/'
+                }
+            }
+        }
+    }
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists