[WIP] Added golangci-lint for linting and fixed detected linting issues

.golangci.yml

@@ -0,0 +1,81 @@
+# This file contains all available configuration options
+# with their default values.
+
+# options for analysis running
+run:
+  # default concurrency is a available CPU number
+  concurrency: 4
+
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  timeout: 1m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+  # which dirs to skip: issues from them won't be reported;
+  # can use regexp here: generated.*, regexp is applied on full path;
+  # default value is empty list, but default dirs are skipped independently
+  # from this option's value (see skip-dirs-use-default).
+  # "/" will be replaced by current OS file path separator to properly work
+  # on Windows.
+  skip-dirs:
+    - vendor
+
+  # default is true. Enables skipping of directories:
+  #   vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
+  skip-dirs-use-default: true
+
+  # by default isn't set. If set we pass it to "go list -mod={option}". From "go help modules":
+  # If invoked with -mod=readonly, the go command is disallowed from the implicit
+  # automatic updating of go.mod described above. Instead, it fails when any changes
+  # to go.mod are needed. This setting is most useful to check that go.mod does
+  # not need updates, such as in a continuous integration and testing system.
+  # If invoked with -mod=vendor, the go command assumes that the vendor
+  # directory holds the correct copies of dependencies and ignores
+  # the dependency descriptions in go.mod.
+  modules-download-mode: vendor
+
+  # Allow multiple parallel golangci-lint instances running.
+  # If false (default) - golangci-lint acquires file lock on start.
+  allow-parallel-runners: false
+
+
+# output configuration options
+output:
+  # colored-line-number|line-number|json|tab|checkstyle|code-climate|junit-xml|github-actions
+  # default is "colored-line-number"
+  format: tab
+
+  # print lines of code with issue, default is true
+  print-issued-lines: true
+
+  # print linter name in the end of issue text, default is true
+  print-linter-name: true
+
+  # make issues output unique by line, default is true
+  uniq-by-line: true
+
+  # add a prefix to the output file references; default is no prefix
+  path-prefix: ""
+
+  # sorts results by: filepath, line and column
+  sort-results: false
+
+linters:
+  disable-all: true
+  enable:
+    - deadcode
+    - errcheck
+    - gofmt
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - typecheck
+    - unused
+    - varcheck
+  fast: false

Makefile

@@ -1,3 +1,6 @@
+GOLANGCI_LINT_BIN=./bin/golangci-lint
+GOLANGCI_LINT_VERSION=v1.40.1
+
 all: build
 .PHONY: all
 
@@ -21,3 +24,12 @@ verify-codegen-crds:
 verify-codegen: verify-codegen-crds
 verify: verify-codegen
 .PHONY: update-codegen-crds update-codegen verify-codegen-crds verify-codegen verify
+
+
+.PHONY: lint
+## Checks the code with golangci-lint
+lint: $(GOLANGCI_LINT_BIN)
+	./bin/golangci-lint ${V_FLAG} run --deadline=30m
+
+$(GOLANGCI_LINT_BIN):
+	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b ./bin ${GOLANGCI_LINT_VERSION}

cmd/image.go

@@ -31,5 +31,5 @@ func runImageCmd(cmd *cobra.Command, args []string) {
 	if err != nil {
 		klog.Fatalf("error: %v", err)
 	}
-	fmt.Printf(image)
+	fmt.Print(image)
 }

cmd/main.go

@@ -17,7 +17,7 @@ var (
 
 func init() {
 	klog.InitFlags(flag.CommandLine)
-	flag.CommandLine.Set("alsologtostderr", "true")
+	_ = flag.CommandLine.Set("alsologtostderr", "true")
 	rootCmd.PersistentFlags().AddGoFlagSet(flag.CommandLine)
 }
 

cmd/render.go

@@ -31,7 +31,7 @@ func init() {
 }
 
 func runRenderCmd(cmd *cobra.Command, args []string) {
-	flag.Set("logtostderr", "true")
+	_ = flag.Set("logtostderr", "true")
 	flag.Parse()
 
 	if renderOpts.outputDir == "" {

lib/resourcemerge/core.go

@@ -508,16 +508,6 @@ func ensureCapabilities(modified *bool, existing *corev1.Capabilities, required
 	}
 }
 
-func setStringSliceIfSet(modified *bool, existing *[]string, required []string) {
-	if required == nil {
-		return
-	}
-	if !equality.Semantic.DeepEqual(required, *existing) {
-		*existing = required
-		*modified = true
-	}
-}
-
 func setStringSlice(modified *bool, existing *[]string, required []string) {
 	if !reflect.DeepEqual(required, *existing) {
 		*existing = required