Add support for a content dir set per language

A sample config:

```toml
defaultContentLanguage = "en"
defaultContentLanguageInSubdir = true

[Languages]
[Languages.en]
weight = 10
title = "In English"
languageName = "English"
contentDir = "content/english"

[Languages.nn]
weight = 20
title = "På Norsk"
languageName = "Norsk"
contentDir = "content/norwegian"
```

The value of `contentDir` can be any valid path, even absolute path references. The only restriction is that the content dirs cannot overlap.

The content files will be assigned a language by

1. The placement: `content/norwegian/post/my-post.md` will be read as Norwegian content.
2. The filename: `content/english/post/my-post.nn.md` will be read as Norwegian even if it lives in the English content folder.

The content directories will be merged into a big virtual filesystem with one simple rule: The most specific language file will win.
This means that if both `content/norwegian/post/my-post.md` and `content/english/post/my-post.nn.md` exists, they will be considered duplicates and the version inside `content/norwegian` will win.

Note that translations will be automatically assigned by Hugo by the content file's relative placement, so `content/norwegian/post/my-post.md` will be a translation of `content/english/post/my-post.md`.

If this does not work for you, you can connect the translations together by setting a `translationKey` in the content files' front matter.

Fixes #4523
Fixes #4552
Fixes #4553

1 files changed, 6 insertions, 2 deletions

diff --git a/commands/hugo.go b/commands/hugo.go
index a5b2c8895..ba8c0aef4 100644
--- a/commands/hugo.go
+++ b/commands/hugo.go
@@ -705,7 +705,7 @@ func (c *commandeer) getDirList() ([]string, error) {
 					c.Logger.ERROR.Printf("Cannot read symbolic link '%s', error was: %s", path, err)
 					return nil
 				}
-				linkfi, err := helpers.LstatIfOs(c.Fs.Source, link)
+				linkfi, err := helpers.LstatIfPossible(c.Fs.Source, link)
 				if err != nil {
 					c.Logger.ERROR.Printf("Cannot stat %q: %s", link, err)
 					return nil
@@ -743,9 +743,13 @@ func (c *commandeer) getDirList() ([]string, error) {
 
 	// SymbolicWalk will log anny ERRORs
 	_ = helpers.SymbolicWalk(c.Fs.Source, dataDir, regularWalker)
-	_ = helpers.SymbolicWalk(c.Fs.Source, c.PathSpec().AbsPathify(c.Cfg.GetString("contentDir")), symLinkWalker)
 	_ = helpers.SymbolicWalk(c.Fs.Source, i18nDir, regularWalker)
 	_ = helpers.SymbolicWalk(c.Fs.Source, layoutDir, regularWalker)
+
+	for _, contentDir := range c.PathSpec().ContentDirs() {
+		_ = helpers.SymbolicWalk(c.Fs.Source, contentDir.Value, symLinkWalker)
+	}
+
 	for _, staticDir := range staticDirs {
 		_ = helpers.SymbolicWalk(c.Fs.Source, staticDir, regularWalker)
 	}