Switch to using Github Actions CI

MiMa binary compatibility checks are now run on master, but the
mimaPreviousArtifacts are empty which makes the check a no-op. This
helps keep both the build.sbt and CI more consistent between master and
stable branches.

.mergify.yml is also updated with mergify.sc from chisel-repo-tools
using the following configuration:

conditions:
  - status-success=all tests passed
branches:
  - 3.2.x
  - 3.3.x
  - 3.4.x

.github/workflows/test.yml

@@ -0,0 +1,45 @@
+name: Continuous Integration
+
+on: [pull_request]
+
+jobs:
+  ci:
+    name: ci
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        scala: [2.12.12, 2.11.12]
+    container:
+      image: ucbbar/chisel3-tools
+      options: --user github --entrypoint /bin/bash
+    env:
+      CONTAINER_HOME: /home/github
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Scala
+        uses: olafurpg/setup-scala@v10
+        with:
+          java-version: adopt@1.8
+      - name: Cache Scala
+        uses: coursier/cache-action@v5
+      - name: Documentation (Scala 2.12 only)
+        if: matrix.scala == '2.12.12'
+        run: sbt ++${{ matrix.scala }} docs/mdoc
+      - name: Test
+        run: sbt ++${{ matrix.scala }} test
+      - name: Binary compatibility
+        run: sbt ++${{ matrix.scala }} mimaReportBinaryIssues
+
+
+  # Sentinel job to simplify how we specify which checks need to pass in branch
+  # protection and in Mergify
+  #
+  # When adding new jobs, please add them to `needs` below
+  all_tests_passed:
+    name: "all tests passed"
+    needs: [ci]
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo Success!

.mergify.yml

@@ -1,135 +1,107 @@
 pull_request_rules:
-  - name: remove outdated reviews
-    conditions:
-      - base=master
-    actions:
-      dismiss_reviews:
+- name: automatic squash-and-merge on CI success and review
+  conditions:
+  - status-success=all tests passed
+  - '#approved-reviews-by>=1'
+  - '#changes-requested-reviews-by=0'
+  - base=master
+  - label="Please Merge"
+  - label!="DO NOT MERGE"
+  - label!="bp-conflict"
+  actions:
+    merge:
+      method: squash
+      strict: smart
+      strict_method: merge
+- name: backport to 3.4.x
+  conditions:
+  - merged
+  - base=master
+  - milestone=3.4.x
+  actions:
+    backport:
+      branches:
+      - 3.4.x
+      ignore_conflicts: true
+      label_conflicts: bp-conflict
+    label:
+      add:
+      - Backported
+- name: backport to 3.3.x, 3.4.x
+  conditions:
+  - merged
+  - base=master
+  - milestone=3.3.x
+  actions:
+    backport:
+      branches:
+      - 3.3.x
+      - 3.4.x
+      ignore_conflicts: true
+      label_conflicts: bp-conflict
+    label:
+      add:
+      - Backported
+- name: backport to 3.2.x, 3.3.x, 3.4.x
+  conditions:
+  - merged
+  - base=master
+  - milestone=3.2.x
+  actions:
+    backport:
+      branches:
+      - 3.2.x
+      - 3.3.x
+      - 3.4.x
+      ignore_conflicts: true
+      label_conflicts: bp-conflict
+    label:
+      add:
+      - Backported
+- name: label Mergify backport PR
+  conditions:
+  - body~=This is an automated backport of pull request \#\d+ done by Mergify
+  actions:
+    label:
+      add:
+      - Backport
+- name: automatic squash-and-mege of 3.2.x backport PRs
+  conditions:
+  - status-success=all tests passed
+  - '#changes-requested-reviews-by=0'
+  - base=3.2.x
+  - label="Backport"
+  - label!="DO NOT MERGE"
+  - label!="bp-conflict"
+  actions:
+    merge:
+      method: squash
+      strict: smart
+      strict_method: merge
+- name: automatic squash-and-mege of 3.3.x backport PRs
+  conditions:
+  - status-success=all tests passed
+  - '#changes-requested-reviews-by=0'
+  - base=3.3.x
+  - label="Backport"
+  - label!="DO NOT MERGE"
+  - label!="bp-conflict"
+  actions:
+    merge:
+      method: squash
+      strict: smart
+      strict_method: merge
+- name: automatic squash-and-mege of 3.4.x backport PRs
+  conditions:
+  - status-success=all tests passed
+  - '#changes-requested-reviews-by=0'
+  - base=3.4.x
+  - label="Backport"
+  - label!="DO NOT MERGE"
+  - label!="bp-conflict"
+  actions:
+    merge:
+      method: squash
+      strict: smart
+      strict_method: merge
 
-pull_request_rules:
-  - name: automatic squash-and-merge on CI success and review
-    conditions:
-      - "status-success=ci/circleci: build-firrtl"
-      - "status-success=ci/circleci: build-prep"
-      - "status-success=ci/circleci: test-chisel-2_11"
-      - "status-success=ci/circleci: test-chisel-2_12"
-      - status-success=license/cla
-      - "#approved-reviews-by>=1"
-      - "#changes-requested-reviews-by=0"
-      - base=master
-      - label="Please Merge"
-      - label!="DO NOT MERGE"
-      - label!="bp-conflict"
-    actions:
-      merge:
-        method: squash
-        strict: smart
-        strict_method: merge
-
-  - name: backport to 3.4.x
-    conditions:
-      - merged
-      - base=master
-      - milestone=3.4.x
-    actions:
-      backport:
-        branches:
-          - 3.4.x
-        ignore_conflicts: True
-        label_conflicts: "bp-conflict"
-      label:
-        add: [Backported]
-
-  - name: backport to 3.3.x and 3.4.x
-    conditions:
-      - merged
-      - base=master
-      - milestone=3.3.x
-    actions:
-      backport:
-        branches:
-          - 3.3.x
-          - 3.4.x
-        ignore_conflicts: True
-        label_conflicts: "bp-conflict"
-      label:
-        add: [Backported]
-
-  - name: backport to 3.2.x, 3.3.x, and 3.4.x
-    conditions:
-      - merged
-      - base=master
-      - milestone=3.2.x
-    actions:
-      backport:
-        branches:
-          - 3.2.x
-          - 3.3.x
-          - 3.4.x
-        ignore_conflicts: True
-        label_conflicts: "bp-conflict"
-      label:
-        add: [Backported]
-
-  - name: label Mergify backport PR
-    conditions:
-      - body~=This is an automated backport of pull request \#\d+ done by Mergify
-    actions:
-      label:
-        add: [Backport]
-
-  - name: automatic squash-and-merge of 3.4.x backport PRs
-    conditions:
-      - "status-success=ci/circleci: build-firrtl"
-      - "status-success=ci/circleci: build-prep"
-      - "status-success=ci/circleci: test-chisel-2_11"
-      - "status-success=ci/circleci: test-chisel-2_12"
-      - "status-success=ci/circleci: check-binary-compatibility"
-      - status-success=license/cla
-      - "#changes-requested-reviews-by=0"
-      - base=3.4.x
-      - label="Backport"
-      - label!="DO NOT MERGE"
-      - label!="bp-conflict"
-    actions:
-      merge:
-        method: squash
-        strict: smart
-        strict_method: merge
-
-  - name: automatic squash-and-merge of 3.3.x backport PRs
-    conditions:
-      - "status-success=ci/circleci: build-firrtl"
-      - "status-success=ci/circleci: build-prep"
-      - "status-success=ci/circleci: test-chisel-2_11"
-      - "status-success=ci/circleci: test-chisel-2_12"
-      - "status-success=ci/circleci: check-binary-compatibility"
-      - status-success=license/cla
-      - "#changes-requested-reviews-by=0"
-      - base=3.3.x
-      - label="Backport"
-      - label!="DO NOT MERGE"
-      - label!="bp-conflict"
-    actions:
-      merge:
-        method: squash
-        strict: smart
-        strict_method: merge
-
-  - name: automatic squash-and-merge of 3.2.x backport PRs
-    conditions:
-      - "status-success=ci/circleci: build-firrtl"
-      - "status-success=ci/circleci: build-prep"
-      - "status-success=ci/circleci: test-chisel-2_11"
-      - "status-success=ci/circleci: test-chisel-2_12"
-      - "status-success=ci/circleci: check-binary-compatibility"
-      - status-success=license/cla
-      - "#changes-requested-reviews-by=0"
-      - base=3.2.x
-      - label="Backport"
-      - label!="DO NOT MERGE"
-      - label!="bp-conflict"
-    actions:
-      merge:
-        method: squash
-        strict: smart
-        strict_method: merge

build.sbt

@@ -147,6 +147,13 @@ lazy val plugin = (project in file("plugin")).
     },
     // Only publish for Scala 2.12
     publish / skip := !scalaVersion.value.startsWith("2.12")
+  ).
+  settings(
+    mimaPreviousArtifacts := {
+      // Not published for 2.11, do not try to check binary compatibility with a 2.11 artifact
+      if (scalaVersion.value.startsWith("2.11")) Set()
+      else Set()
+    }
   )
 
 lazy val usePluginSettings = Seq(
@@ -163,7 +170,8 @@ lazy val usePluginSettings = Seq(
 lazy val macros = (project in file("macros")).
   settings(name := "chisel3-macros").
   settings(commonSettings: _*).
-  settings(publishSettings: _*)
+  settings(publishSettings: _*).
+  settings(mimaPreviousArtifacts := Set())
 
 lazy val firrtlRef = ProjectRef(workspaceDirectory / "firrtl", "firrtl")
 
@@ -177,6 +185,7 @@ lazy val core = (project in file("core")).
     buildInfoKeys := Seq[BuildInfoKey](buildInfoPackage, version, scalaVersion, sbtVersion)
   ).
   settings(publishSettings: _*).
+  settings(mimaPreviousArtifacts := Set()).
   settings(
     name := "chisel3-core",
     scalacOptions := scalacOptions.value ++ Seq(
@@ -205,6 +214,7 @@ lazy val chisel = (project in file(".")).
   dependsOn(core).
   aggregate(macros, core, plugin).
   settings(
+    mimaPreviousArtifacts := Set(),
     libraryDependencies += defaultVersions("treadle") % "test",
     scalacOptions in Test ++= Seq("-language:reflectiveCalls"),
     scalacOptions in Compile in doc ++= Seq(

project/plugins.sbt

@@ -20,5 +20,7 @@ addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.2.5" )
 
 addSbtPlugin("com.eed3si9n" % "sbt-sriracha" % "0.1.0")
 
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.8.1")
+
 // From FIRRTL for building from source
 addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.19")