Reimplement lint with improved compatibility

Specifically, Darwin's bash is very old so it doesn't support newer
features like `declare -A`.  Reduce the complexity of the script
so that it can be used for all platforms.  Comment heavily regarding the
scripts various execution contexts to prevent developers relying on
advanced features for any future modifications.

Signed-off-by: Chris Evich <cevich@redhat.com>

hack/golangci-lint.sh

@@ -1,46 +1,45 @@
-#!/usr/bin/env bash
+#!/bin/bash
 
 # Need to run linter twice to cover all the build tags code paths
 set -e
 
-# Dedicated block for Darwin: OS doesn't support the rest of this
+# WARNING: This script executes on multiple operating systems that
-# script, only needs to check 'remote', and its golangci-lint needs
+# do not have the same version of Bash.  Specifically, Darwin uses
-# specialized arguments.
+# a very old version, where modern features (like `declare -A`) are
-if [[ $(uname -s) == "Darwin" ]] || [[ "$GOOS" == "darwin" ]]; then
+# absent.
-  declare -a DARWIN_SKIP_DIRS
-  DARWIN_SKIP_DIRS=(
-    libpod/events
-    pkg/api
-    pkg/domain/infra/abi
-    pkg/machine/qemu
-    pkg/trust
-    test
-  )
-  echo ""
-  echo Running golangci-lint for "remote"
-  echo Build Tags          "remote": remote
-  echo Skipped directories "remote": ${DARWIN_SKIP_DIRS[*]}
-  ./bin/golangci-lint run --build-tags="remote" \
-    --skip-dirs=$(tr ' ' ',' <<<"${DARWIN_SKIP_DIRS[@]}")
-  exit 0  # All done, don't execute anything below, it will break on Darwin
-fi
-
-declare -A BUILD_TAGS
-BUILD_TAGS[default]="apparmor,seccomp,selinux"
-BUILD_TAGS[abi]="${BUILD_TAGS[default]},systemd"
-BUILD_TAGS[tunnel]="${BUILD_TAGS[default]},remote"
-
-declare -A SKIP_DIRS
-SKIP_DIRS[abi]=""
-# TODO: add "remote" build tag to pkg/api
-SKIP_DIRS[tunnel]="pkg/api,pkg/domain/infra/abi"
 
+# Makefile calls script with the 'run' argument, but developers may not.
+# Handle both cases transparently.
 [[ $1 == run ]] && shift
 
-for i in tunnel abi; do
+BUILD_TAGS_DEFAULT="apparmor,seccomp,selinux"
+BUILD_TAGS_ABI="$BUILD_TAGS_DEFAULT,systemd"
+BUILD_TAGS_TUNNEL="$BUILD_TAGS_DEFAULT,remote"
+BUILD_TAGS_REMOTE="remote"
+
+SKIP_DIRS_ABI=""
+SKIP_DIRS_TUNNEL="pkg/api,pkg/domain/infra/abi"
+SKIP_DIRS_REMOTE="libpod/events,pkg/api,pkg/domain/infra/abi,pkg/machine/qemu,pkg/trust,test"
+
+declare -a to_lint
+to_lint=(ABI TUNNEL REMOTE)
+
+# Special-case, for Darwin and Windows only "remote" linting is possible and required.
+if [[ "$GOOS" == "windows" ]] || [[ "$GOOS" == "darwin" ]]; then
+  to_lint=(REMOTE)
+fi
+
+for to_lint in "${to_lint[@]}"; do
+  tags_var="BUILD_TAGS_${to_lint}"
+  skip_var="SKIP_DIRS_${to_lint}"
   echo ""
-  echo Running golangci-lint for "$i"
+  echo Running golangci-lint for "$to_lint"
-  echo Build Tags          "$i": ${BUILD_TAGS[$i]}
+  echo Build Tags          "$to_lint": ${!tags_var}
-  echo Skipped directories "$i": ${SKIP_DIRS[$i]}
+  echo Skipped directories "$to_lint": ${!skip_var}
-  ./bin/golangci-lint run --build-tags=${BUILD_TAGS[$i]} --skip-dirs=${SKIP_DIRS[$i]} "$@"
+  (
+    # Make it really easy for a developer to copy-paste the command-line
+    # to focus or debug a single, specific linting category.
+    set -x
+    ./bin/golangci-lint run --build-tags="${!tags_var}" --skip-dirs="${!skip_var}" "$@"
+  )
 done