From 9646482274d01f82b74200da5598b5964c2ea828 Mon Sep 17 00:00:00 2001
From: Abhinav Gupta <abg@uber.com>
Date: Wed, 4 Mar 2020 11:39:36 -0800
Subject: [PATCH] Add staticcheck and fix issues

This adds staticcheck as a linter to Zap and fixes issues found by it.
Specifically, it found a few unused unexported types and functions.
---
 Makefile                | 8 +++++++-
 go.mod                  | 1 +
 sugar_test.go           | 4 ----
 tools_test.go           | 1 +
 zapcore/encoder_test.go | 8 --------
 zapcore/error.go        | 5 -----
 6 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/Makefile b/Makefile
index 21e436c45..dfaf6406e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 export GOBIN ?= $(shell pwd)/bin
 
 GOLINT = $(GOBIN)/golint
+STATICCHECK = $(GOBIN)/staticcheck
 BENCH_FLAGS ?= -cpuprofile=cpu.pprof -memprofile=mem.pprof -benchmem
 
 # Directories containing independent Go modules.
@@ -17,7 +18,7 @@ GO_FILES := $(shell \
 all: lint test
 
 .PHONY: lint
-lint: $(GOLINT)
+lint: $(GOLINT) $(STATICCHECK)
 	@rm -rf lint.log
 	@echo "Checking formatting..."
 	@gofmt -d -s $(GO_FILES) 2>&1 | tee lint.log
@@ -25,6 +26,8 @@ lint: $(GOLINT)
 	@$(foreach dir,$(MODULE_DIRS),(cd $(dir) && go vet ./... 2>&1) &&) true | tee -a lint.log
 	@echo "Checking lint..."
 	@$(foreach dir,$(MODULE_DIRS),(cd $(dir) && $(GOLINT) ./... 2>&1) &&) true | tee -a lint.log
+	@echo "Checking staticcheck..."
+	@$(foreach dir,$(MODULE_DIRS),(cd $(dir) && $(STATICCHECK) ./... 2>&1) &&) true | tee -a lint.log
 	@echo "Checking for unresolved FIXMEs..."
 	@git grep -i fixme | grep -v -e Makefile | tee -a lint.log
 	@echo "Checking for license headers..."
@@ -34,6 +37,9 @@ lint: $(GOLINT)
 $(GOLINT):
 	go install golang.org/x/lint/golint
 
+$(STATICCHECK):
+	go install honnef.co/go/tools/cmd/staticcheck
+
 .PHONY: test
 test:
 	@$(foreach dir,$(MODULE_DIRS),(cd $(dir) && go test -race ./...) &&) true
diff --git a/go.mod b/go.mod
index 8e974d826..118abda15 100644
--- a/go.mod
+++ b/go.mod
@@ -8,4 +8,5 @@ require (
 	go.uber.org/atomic v1.6.0
 	go.uber.org/multierr v1.5.0
 	golang.org/x/lint v0.0.0-20190930215403-16217165b5de
+	honnef.co/go/tools v0.0.1-2019.2.3
 )
diff --git a/sugar_test.go b/sugar_test.go
index 5b1dcfacd..5f4bb83b9 100644
--- a/sugar_test.go
+++ b/sugar_test.go
@@ -159,10 +159,6 @@ func TestSugarFieldsInvalidPairs(t *testing.T) {
 	})
 }
 
-type stringerF func() string
-
-func (f stringerF) String() string { return f() }
-
 func TestSugarStructuredLogging(t *testing.T) {
 	tests := []struct {
 		msg       string
diff --git a/tools_test.go b/tools_test.go
index 2b6366bea..67e9f5801 100644
--- a/tools_test.go
+++ b/tools_test.go
@@ -25,4 +25,5 @@ package zap
 import (
 	// Tools we use during development.
 	_ "golang.org/x/lint/golint"
+	_ "honnef.co/go/tools/cmd/staticcheck"
 )
diff --git a/zapcore/encoder_test.go b/zapcore/encoder_test.go
index 3f521971a..54556b8d4 100644
--- a/zapcore/encoder_test.go
+++ b/zapcore/encoder_test.go
@@ -67,14 +67,6 @@ func humanEncoderConfig() EncoderConfig {
 	return cfg
 }
 
-func withJSONEncoder(f func(Encoder)) {
-	f(NewJSONEncoder(testEncoderConfig()))
-}
-
-func withConsoleEncoder(f func(Encoder)) {
-	f(NewConsoleEncoder(humanEncoderConfig()))
-}
-
 func capitalNameEncoder(loggerName string, enc PrimitiveArrayEncoder) {
 	enc.AppendString(strings.ToUpper(loggerName))
 }
diff --git a/zapcore/error.go b/zapcore/error.go
index a67c7bacc..9ba2272c3 100644
--- a/zapcore/error.go
+++ b/zapcore/error.go
@@ -66,11 +66,6 @@ type errorGroup interface {
 	Errors() []error
 }
 
-type causer interface {
-	// Provides access to the error that caused this error.
-	Cause() error
-}
-
 // Note that errArry and errArrayElem are very similar to the version
 // implemented in the top-level error.go file. We can't re-use this because
 // that would require exporting errArray as part of the zapcore API.