deprecate <1.12.x, use golangci-lint (spf13#876)

* deprecate go 1.10.x and 1.11.x
* use golangci-lint in Travis CI
* fix linting issues accordingly

.circleci/config.yml

@@ -8,6 +8,7 @@ references:
     run:
       name: "All Commands"
       command: |
+        export GO111MODULE=on
         mkdir -p bin
         curl -Lso bin/shellcheck https://github.com/caarlos0/shellcheck-docker/releases/download/v0.4.6/shellcheck
         chmod +x bin/shellcheck
@@ -29,13 +30,6 @@ jobs:
       - run:
           name: "Check formatting"
           command: diff -u <(echo -n) <(gofmt -d -s .)
-  go-previous:
-    docker:
-      - image: circleci/golang:1.11
-    working_directory: *workspace
-    steps:
-      - checkout
-      - *run_tests
   go-latest:
     docker:
       - image: circleci/golang:latest
@@ -49,5 +43,4 @@ workflows:
   main:
     jobs:
       - go-current
-      - go-previous
       - go-latest

.gitattributes

@@ -0,0 +1 @@
+* text=auto

.gitignore

@@ -37,3 +37,6 @@ cobra.test
 
 .idea/
 *.iml
+
+# test-generated files
+cobra/cmd/testproject

.golangci.yml

@@ -0,0 +1,25 @@
+run:
+  deadline: 5m
+
+linters:
+  enable:
+    - deadcode
+    - errcheck
+    - gas
+    - goconst
+    - goimports
+    - golint
+    - govet
+    - ineffassign
+    - interfacer
+    - maligned
+    - megacheck
+    - structcheck
+    - unconvert
+    - varcheck
+  enable-all: false
+  disable-all: true
+#  presets:
+#    - bugs
+#    - unused
+  fast: false

.travis.yml

@@ -1,31 +1,27 @@
 language: go
 
 stages:
-  - diff
+  - lint
   - test
 
 go:
-  - 1.11.x
   - 1.12.x
   - 1.13.x
   - tip
 
-env:
-  - GO111MODULE=on
-
-matrix:
-  allow_failures:
-    - go: tip
-  include:
-    - stage: diff
-      go: 1.13.x
-      script: diff -u <(echo -n) <(gofmt -d -s .)
+env: GO111MODULE=on
 
 before_install: go get -u github.com/kyoh86/richgo
 
 script:
   - richgo test -v ./...
   - go build
-  - if [ -z $NOVET ]; then
-      diff -u <(echo -n) <(go vet . 2>&1 | grep -vE 'ExampleCommand|bash_completions.*Fprint');
-    fi
+
+matrix:
+  allow_failures:
+    - go: tip
+  include:
+    - stage: lint
+      go: 1.13.x
+      before_install: go get github.com/golangci/golangci-lint/cmd/golangci-lint@v1.19.1
+      script: golangci-lint run -v