Introduce buf checks [KVL-980] (#10411)

CHANGELOG_BEGIN
CHANGELOG_END

buf.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2021 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+version: v1beta1
+build:
+  roots:
+    - daml-lf/archive/src/main/protobuf/
+    - daml-lf/transaction/src/main/protobuf/
+    - ledger/ledger-configuration/protobuf/
+    - ledger/participant-state/kvutils/src/main/protobuf/
+  excludes:
+    # We have to exclude these to avoid duplicate definitions of e.g. Unit within the same package.
+    - daml-lf/archive/src/main/protobuf/com/daml/daml_lf_1_11/
+    - daml-lf/archive/src/main/protobuf/com/daml/daml_lf_1_12/
+    - daml-lf/archive/src/main/protobuf/com/daml/daml_lf_1_13/
+    - daml-lf/archive/src/main/protobuf/com/daml/daml_lf_1_14/
+    - daml-lf/archive/src/main/protobuf/com/digitalasset/
+
+lint:
+  use:
+    - DEFAULT
+  except:
+    - PACKAGE_VERSION_SUFFIX
+
+breaking:
+  use:
+    - WIRE_JSON

dev-env/bin/buf

@@ -0,0 +1 @@
+../lib/dade-exec-nix-tool

fmt.sh

@@ -11,6 +11,11 @@ cd "$(dirname "$0")"
 # load the dev-env
 eval "$(dev-env/bin/dade-assist)"
 
+# Location of reference image used for buf breaking check.
+# In case breaking changes have been introduced, running './fmt.sh --rebuild-buf-image' will
+# overwrite this image.
+buf_image="buf_image.bin"
+
 ## Config ##
 is_test=
 scalafmt_args=()
@@ -62,6 +67,7 @@ Usage: ./fmt.sh [options]
 Options:
   -h, --help: shows this help
   --test:     only test for formatting changes, used by CI
+  --rebuild-buf-image:  rebuilds reference image used for buf breaking checks
 USAGE
       exit
       ;;
@@ -79,6 +85,11 @@ USAGE
       scalafmt_args+=('--mode=diff' "--diff-branch=${merge_base}")
       diff_mode=true
       ;;
+    --rebuild-buf-image)
+      shift
+      run buf build -o "${buf_image}"
+      exit
+      ;;
     *)
       echo "fmt.sh: unknown argument $1" >&2
       exit 1
@@ -144,6 +155,9 @@ run scalafmt "${scalafmt_args[@]:-}"
 # check for Bazel build files code formatting
 run bazel run "$buildifier_target"
 
+# Run buf checks.
+run buf check breaking --against "${buf_image}"
+
 # Note that we cannot use a symlink here because Windows.
 if ! diff .bazelrc compatibility/.bazelrc >/dev/null; then
     echo ".bazelrc and  compatibility/.bazelrc are out of sync:"

nix/default.nix

@@ -78,6 +78,8 @@ in rec {
 
     javafmt = pkgs.callPackage ./tools/google-java-format {};
 
+    buf = pkgs.buf;
+
     scala = bazel_dependencies.scala_2_13;
     fsc      = scala;
     scalac   = scala;