goheader: fix relative template path

go-header template-path setting is usually a relative filepath. As a
result, the linter only worked when golangci-lint was invoked from that
folder.

We detect if the template path is relative and prefix it with config
path.

go-header_bad.go test case was modified because old files are not
checked as seen here
https://github.com/denis-tingaikin/go-header/blob/v0.4.3/analyzer.go#L59-L63

pkg/config/linters_settings.go

@@ -478,9 +478,10 @@ type GofumptSettings struct {
 }
 
 type GoHeaderSettings struct {
-	Values       map[string]map[string]string `mapstructure:"values"`
-	Template     string                       `mapstructure:"template"`
-	TemplatePath string                       `mapstructure:"template-path"`
+	Values        map[string]map[string]string `mapstructure:"values"`
+	Template      string                       `mapstructure:"template"`
+	TemplatePath  string                       `mapstructure:"template-path"`
+	LintConfigDir string                       `mapstructure:"lint-config-dir"`
 }
 
 type GoImportsSettings struct {

pkg/golinters/goheader.go

@@ -2,6 +2,7 @@ package golinters
 
 import (
 	"go/token"
+	"path/filepath"
 	"sync"
 
 	goheader "github.com/denis-tingaikin/go-header"
@@ -21,10 +22,14 @@ func NewGoHeader(settings *config.GoHeaderSettings) *goanalysis.Linter {
 
 	conf := &goheader.Configuration{}
 	if settings != nil {
+		path := settings.TemplatePath
+		if path != "" && !filepath.IsAbs(path) {
+			path = filepath.Join(settings.LintConfigDir, path)
+		}
 		conf = &goheader.Configuration{
 			Values:       settings.Values,
 			Template:     settings.Template,
-			TemplatePath: settings.TemplatePath,
+			TemplatePath: path,
 		}
 	}
 

pkg/lint/lintersdb/manager.go

@@ -247,6 +247,10 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 		if stylecheckCfg != nil && stylecheckCfg.GoVersion != "" {
 			stylecheckCfg.GoVersion = trimGoVersion(m.cfg.Run.Go)
 		}
+
+		if goheaderCfg != nil {
+			goheaderCfg.LintConfigDir = m.cfg.GetConfigDir()
+		}
 	}
 
 	const megacheckName = "megacheck"

test/testdata/configs/go-header-template

@@ -0,0 +1 @@
+MY {{title}}

test/testdata/configs/go-header-template.yml

@@ -0,0 +1,6 @@
+linters-settings:
+  goheader:
+    template-path: go-header-template
+    values:
+      const:
+        title: TITLE.

test/testdata/configs/go-header.yml

@@ -1,6 +1,6 @@
 linters-settings:
   goheader:
-    template: MY {{title}}
+    template: "MY {{title}}"
     values:
       const:
         title: TITLE.

test/testdata/go-header-template_good.go

@@ -0,0 +1,6 @@
+/*MY TITLE.*/
+
+//golangcitest:args -Egoheader
+//golangcitest:config_path testdata/configs/go-header-template.yml
+//golangcitest:expected_exitcode 0
+package testdata

test/testdata/go-header_bad.go

@@ -1,4 +1,4 @@
-/*MY TITLE!*/ // want `Expected:TITLE\., Actual: TITLE!`
+/*MY TITLE?*/ // want `Expected:TITLE\., Actual: TITLE?`
 
 //golangcitest:args -Egoheader
 //golangcitest:config_path testdata/configs/go-header.yml