Default to ~/.config/gmailctl for newly created config dirs. (#455)

* Default to ~/.config/gmailctl for newly created config dirs.

This is a minimal fix for #144

It is a revision of #393 and uses a library for the internal XDG path calculation per feedback there.

* Update cmd/gmailctl/cmd/root_cmd.go

Co-authored-by: Michele Bertasi <405934+mbrt@users.noreply.github.com>

* Update README.md

---------

Co-authored-by: Michele Bertasi <405934+mbrt@users.noreply.github.com>

Author: lgarron

README.md

@@ -13,6 +13,7 @@ label, archive and manage your inbox automatically.
   - [Motivation](#motivation)
   - [Install](#install)
   - [Usage](#usage)
+    - [Config directory](#config-directory)
     - [Migrate from another solution](#migrate-from-another-solution)
     - [Other commands](#other-commands)
   - [Configuration](#configuration)
@@ -136,17 +137,24 @@ settings without leaving your command line.
 [![asciicast](https://asciinema.org/a/1NIWhzeJNcrN7cCe7mGjWQQnx.svg)](https://asciinema.org/a/1NIWhzeJNcrN7cCe7mGjWQQnx)
 
 The easiest way to use gmailctl is to run `gmailctl edit`. This will open the
-local `.gmailctl/config.jsonnet` file in your editor. After you exit the editor
-the configuration is applied to Gmail. See [Configuration](#configuration) for
-the configuration file format. This is the preferred way if you want to start
-your filters from scratch.
+local config file in your editor. After you exit
+the editor the configuration is applied to Gmail. See
+[Configuration](#configuration) for the configuration file format. This is the
+preferred way if you want to start your filters from scratch.
 
 **NOTE:** It's recommended to backup your current configuration before you apply
 the generated one for the first time. Your current filters will be wiped and
 replaced with the ones specified in the config file. The diff you'll get during
 the first run will probably be pretty big, but from that point on, all changes
 should generate a small and simple to review diff.
 
+### Config directory
+
+Configuration and credentials are in either:
+
+- `<XDG_BASE_DIR>/gmailctl` (using the [XDG base directory spec](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html), commonly `~/.config/gmailctl` on Linux.
+- `~/.gmailctl`: The previous default location. If the directory exists `gmailctl` will continue to use it for backward compatibility
+- Custom location: use the `--config` argument.
 ### Migrate from another solution
 
 If you want to preserve your current filters and migrate to a more sane
@@ -164,7 +172,8 @@ Example of usage:
 
 ```bash
 # download the filters to the default configuration file
-gmailctl download > ~/.gmailctl/config.jsonnet
+mkdir -p ~/.config/gmailctl
+gmailctl download > ~/.config/gmailctl/config.jsonnet
 # check that the diff is empty and no errors are present
 gmailctl diff
 # happy editing!

cmd/gmailctl/cmd/root_cmd.go

@@ -6,6 +6,7 @@ import (
 	"os/user"
 	"path"
 
+	"github.com/adrg/xdg"
 	"github.com/mattn/go-isatty"
 	"github.com/spf13/cobra"
 )
@@ -53,7 +54,7 @@ func init() {
 	// Here you will define your flags and configuration settings.
 	// Cobra supports persistent flags, which, if defined here,
 	// will be global for your application.
-	rootCmd.PersistentFlags().StringVar(&cfgDir, "config", "", "config directory (default is $HOME/.gmailctl)")
+	rootCmd.PersistentFlags().StringVar(&cfgDir, "config", "", "config directory (defaults to $HOME/.gmailctl if it exists, else $HOME/.config/gmailctl)")
 	rootCmd.PersistentFlags().StringVar(&colorFlag, "color", "auto",
 		"whether to enable color output ('always', 'auto' or 'never')")
 	rootCmd.PersistentFlags().Lookup("color").NoOptDefVal = "always"
@@ -71,7 +72,13 @@ func initConfig() {
 		fmt.Println(err)
 		os.Exit(1)
 	}
-	cfgDir = path.Join(usr.HomeDir, ".gmailctl")
+
+	legacyCfgDir := path.Join(usr.HomeDir, ".gmailctl")
+	if _, err := os.Stat(legacyCfgDir); err != nil && os.IsNotExist(err) {
+		cfgDir = path.Join(xdg.ConfigHome, "gmailctl")
+	} else {
+		cfgDir = legacyCfgDir
+	}
 }
 
 // shouldUseColorDiff decides, based on the value of the color flag and other

go.mod

@@ -5,6 +5,7 @@ go 1.25.0
 toolchain go1.26.1
 
 require (
+	github.com/adrg/xdg v0.5.3
 	github.com/fatih/color v1.18.1-0.20251010072730-26fd5780133d
 	github.com/google/go-jsonnet v0.21.0
 	github.com/gorilla/mux v1.8.1

go.sum

@@ -4,6 +4,8 @@ cloud.google.com/go/auth/oauth2adapt v0.2.8 h1:keo8NaayQZ6wimpNSmW5OPc283g65QNIi
 cloud.google.com/go/auth/oauth2adapt v0.2.8/go.mod h1:XQ9y31RkqZCcwJWNSx2Xvric3RrU88hAYYbjDWYDL+c=
 cloud.google.com/go/compute/metadata v0.9.0 h1:pDUj4QMoPejqq20dK0Pg2N4yG9zIkYGdBtwLoEkH9Zs=
 cloud.google.com/go/compute/metadata v0.9.0/go.mod h1:E0bWwX5wTnLPedCKqk3pJmVgCBSM6qQI1yTBdEb3C10=
+github.com/adrg/xdg v0.5.3 h1:xRnxJXne7+oWDatRhR1JLnvuccuIeCoBu2rtuLqQB78=
+github.com/adrg/xdg v0.5.3/go.mod h1:nlTsY+NNiCBGCK2tpm09vRqfVzrc2fLmXGpBLF0zlTQ=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=