Add support for home directory expansion for -c/--config flag

This change introduces the ability to use the tilde (`~`) character in your
`-c/--config` flag value to expand your home directory. If invoking this via the
command line with `--config ~/.golangci-lint.yaml`, the user's shell expands the
`~` to the home directory. However, if something is invoking the program for
you (like an editor) it may not do the expansion.

Fixes #289

Signed-off-by: Tim Heckman <t@heckman.io>

Author: theckman

go.mod

@@ -45,6 +45,7 @@ require (
 	github.com/magiconair/properties v1.7.6 // indirect
 	github.com/mattn/go-colorable v0.0.9
 	github.com/mattn/go-isatty v0.0.3 // indirect
+	github.com/mitchellh/go-homedir v1.0.0
 	github.com/mitchellh/go-ps v0.0.0-20170309133038-4fdf99ab2936
 	github.com/mitchellh/mapstructure v0.0.0-20180220230111-00c29f56e238 // indirect
 	github.com/nbutton23/zxcvbn-go v0.0.0-20171102151520-eafdab6b0663 // indirect

go.sum

@@ -95,6 +95,8 @@ github.com/mattn/go-colorable v0.0.9 h1:UVL0vNpWh04HeJXV0KLcaT7r06gOH2l4OW6ddYRU
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-isatty v0.0.3 h1:ns/ykhmWi7G9O+8a448SecJU3nSMBXJfqQkl0upE1jI=
 github.com/mattn/go-isatty v0.0.3/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
+github.com/mitchellh/go-homedir v1.0.0 h1:vKb8ShqSby24Yrqr/yDYkuFz8d0WUjys40rvnGC8aR0=
+github.com/mitchellh/go-homedir v1.0.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/go-ps v0.0.0-20170309133038-4fdf99ab2936 h1:kw1v0NlnN+GZcU8Ma8CLF2Zzgjfx95gs3/GN3vYAPpo=
 github.com/mitchellh/go-ps v0.0.0-20170309133038-4fdf99ab2936/go.mod h1:r1VsdOzOPt1ZSrGZWFoNhsAedKnEd6r9Np1+5blZCWk=
 github.com/mitchellh/mapstructure v0.0.0-20180220230111-00c29f56e238 h1:+MZW2uvHgN8kYvksEN3f7eFL2wpzk0GxmlFsMybWc7E=

pkg/config/reader.go

@@ -11,6 +11,8 @@ import (
 
 	"github.com/golangci/golangci-lint/pkg/fsutils"
 	"github.com/golangci/golangci-lint/pkg/logutils"
+
+	"github.com/mitchellh/go-homedir"
 )
 
 type FileReader struct {
@@ -183,5 +185,10 @@ func (r *FileReader) parseConfigOption() (string, error) {
 		return "", errConfigDisabled
 	}
 
+	configFile, err := homedir.Expand(configFile)
+	if err != nil {
+		return "", fmt.Errorf("failed to expand configuration path")
+	}
+
 	return configFile, nil
 }

vendor/github.com/mitchellh/go-homedir/LICENSE

@@ -135,6 +135,8 @@ github.com/magiconair/properties
 github.com/mattn/go-colorable
 # github.com/mattn/go-isatty v0.0.3
 github.com/mattn/go-isatty
+# github.com/mitchellh/go-homedir v1.0.0
+github.com/mitchellh/go-homedir
 # github.com/mitchellh/go-ps v0.0.0-20170309133038-4fdf99ab2936
 github.com/mitchellh/go-ps
 # github.com/mitchellh/mapstructure v0.0.0-20180220230111-00c29f56e238