Add CI check and fix script for go deps

.github/workflows/checkstyle.yaml

@@ -17,6 +17,11 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v1
 
+      - name: Setup go
+        uses: actions/setup-go@v2
+        with:
+          go-version: "1.17.2"
+
       - name: gofmt
         run: |
           gofmt -d . > gofmt-diff.txt || true
@@ -25,18 +30,25 @@ jobs:
 
       - name: buildifier
         run: |
-          go get -u github.com/bazelbuild/buildtools/buildifier
+          go install github.com/bazelbuild/buildtools/buildifier@3.4.0
           "$(go env GOPATH)/bin/buildifier" -d -r . > buildifier-diff.txt || true
           echo "buildifier diff:"
           cat buildifier-diff.txt
 
       - name: gazelle
         run: |
-          go get github.com/bazelbuild/bazel-gazelle/cmd/gazelle
+          go install github.com/bazelbuild/bazel-gazelle/cmd/gazelle@0.23.0
           "$(go env GOPATH)/bin/gazelle" -mode diff > gazelle-diff.txt || true
           echo "gazelle diff:"
           cat gazelle-diff.txt
 
+      - name: go deps
+        run: |
+          go install github.com/bazelbuild/bazel-gazelle/cmd/gazelle@0.23.0
+          GAZELLE_PATH="$(go env GOPATH)/bin/gazelle" tools/fix_go_deps.sh --diff &> go-deps-diff.txt || true
+          echo "go deps diff:"
+          cat go-deps-diff.txt
+
       - name: clang-format
         run: |
           git ls-files | grep '\.proto$' | xargs --no-run-if-empty -d'\n' clang-format -i --style=Google --dry-run &> clang-format-errors.txt || true
@@ -64,12 +76,15 @@ jobs:
           cat buildifier-diff.txt
           echo "===== gazelle diff ====="
           cat gazelle-diff.txt
+          echo "===== go deps diff (fix with tools/fix_go_deps.sh) ====="
+          cat go-deps-diff.txt
           echo "===== clang-format errors ====="
           cat clang-format-errors.txt
           echo "===== prettier errors ====="
           cat prettier-errors.txt
 
           if [ -s gazelle-diff.txt ]; then exit 1; fi
+          if [ -s go-deps-diff.txt ]; then exit 1; fi
           if [ -s gofmt-diff.txt ]; then exit 1; fi
           if [ -s buildifier-diff.txt ]; then exit 1; fi
           if [ -s clang-format-errors.txt ]; then exit 1; fi

tools/fix_go_deps.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+set -euo pipefail
+
+: "${GAZELLE_PATH:=}"
+
+GAZELLE_COMMAND=(bazelisk run //:gazelle --)
+if [[ "$GAZELLE_PATH" ]]; then
+  GAZELLE_COMMAND=("$GAZELLE_PATH")
+fi
+
+DIFF_MODE=0
+if [[ "${1:-}" == "-d" ]] || [[ "${1:-}" == "--diff" ]]; then
+  DIFF_MODE=1
+fi
+
+if ((DIFF_MODE)); then
+  if ! git diff --quiet; then
+    echo >&2 "Git working tree is dirty. To run in diff mode, 'check_go_deps.sh' must be run from a clean tree."
+    git status --short --untracked=no 1>&2
+    exit 1
+  fi
+fi
+
+tmp_log_file=$(mktemp)
+cleanup() {
+  if ((DIFF_MODE)); then
+    git restore go.mod go.sum deps.bzl
+  fi
+  rm -r "$tmp_log_file"
+}
+trap cleanup EXIT
+
+# go mod tidy fails if generated sources are not checked into the repo,
+# and we don't want to require that (yet, at least). So use the `-e`
+# option to ask `go mod tidy` to proceed even if it encounters errors
+# loading packages.
+if ! go mod tidy -e &>"$tmp_log_file"; then
+  echo -e "Command 'go mod tidy -e' failed. Logs:" >&2
+  cat "$tmp_log_file" >&2
+  exit 1
+fi
+
+# Update deps.bzl (using Gazelle)
+if ! "${GAZELLE_COMMAND[@]}" update-repos -from_file=go.mod \
+  -to_macro=deps.bzl%install_buildbuddy_dependencies &>"$tmp_log_file"; then
+  echo -e "Auto-updating 'deps.bzl' failed. Logs:" >&2
+  cat "$tmp_log_file" >&2
+  exit 1
+fi
+
+if ((DIFF_MODE)); then
+  git diff
+fi