Move the mount duplicate filter to the modules package

Also simplify the mount validation logic. There are plenty of ways a user can create mount configs that behaves oddly.

hugolib/config.go

@@ -207,20 +207,28 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 		return v, configFiles, err
 	}
 
-	mods, modulesConfigFiles, err := l.collectModules(modulesConfig, v)
+	// Need to run these after the modules are loaded, but before
+	// they are finalized.
+	collectHook := func(m *modules.ModulesConfig) error {
+		if err := loadLanguageSettings(v, nil); err != nil {
+			return err
+		}
+
+		mods := m.ActiveModules
+
+		// Apply default project mounts.
+		if err := modules.ApplyProjectConfigDefaults(v, mods[len(mods)-1]); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	_, modulesConfigFiles, err := l.collectModules(modulesConfig, v, collectHook)
 	if err != nil {
 		return v, configFiles, err
 	}
 
-	if err := loadLanguageSettings(v, nil); err != nil {
-		return v, configFiles, err
-	}
-
-	// Apply default project mounts.
-	if err := modules.ApplyProjectConfigDefaults(v, mods[len(mods)-1]); err != nil {
-		return v, configFiles, err
-	}
-
 	if len(modulesConfigFiles) > 0 {
 		configFiles = append(configFiles, modulesConfigFiles...)
 	}
@@ -406,7 +414,7 @@ func (l configLoader) loadModulesConfig(v1 *viper.Viper) (modules.Config, error)
 	return modConfig, nil
 }
 
-func (l configLoader) collectModules(modConfig modules.Config, v1 *viper.Viper) (modules.Modules, []string, error) {
+func (l configLoader) collectModules(modConfig modules.Config, v1 *viper.Viper, hookBeforeFinalize func(m *modules.ModulesConfig) error) (modules.Modules, []string, error) {
 	workingDir := l.WorkingDir
 	if workingDir == "" {
 		workingDir = v1.GetString("workingDir")
@@ -420,16 +428,40 @@ func (l configLoader) collectModules(modConfig modules.Config, v1 *viper.Viper)
 	if err != nil {
 		return nil, nil, err
 	}
+
 	v1.Set("filecacheConfigs", filecacheConfigs)
 
+	var configFilenames []string
+
+	hook := func(m *modules.ModulesConfig) error {
+		for _, tc := range m.ActiveModules {
+			if tc.ConfigFilename() != "" {
+				if tc.Watch() {
+					configFilenames = append(configFilenames, tc.ConfigFilename())
+				}
+				if err := l.applyThemeConfig(v1, tc); err != nil {
+					return err
+				}
+			}
+		}
+
+		if hookBeforeFinalize != nil {
+			return hookBeforeFinalize(m)
+		}
+
+		return nil
+
+	}
+
 	modulesClient := modules.NewClient(modules.ClientConfig{
-		Fs:           l.Fs,
-		Logger:       l.Logger,
-		WorkingDir:   workingDir,
-		ThemesDir:    themesDir,
-		CacheDir:     filecacheConfigs.CacheDirModules(),
-		ModuleConfig: modConfig,
-		IgnoreVendor: ignoreVendor,
+		Fs:                 l.Fs,
+		Logger:             l.Logger,
+		HookBeforeFinalize: hook,
+		WorkingDir:         workingDir,
+		ThemesDir:          themesDir,
+		CacheDir:           filecacheConfigs.CacheDirModules(),
+		ModuleConfig:       modConfig,
+		IgnoreVendor:       ignoreVendor,
 	})
 
 	v1.Set("modulesClient", modulesClient)
@@ -442,22 +474,6 @@ func (l configLoader) collectModules(modConfig modules.Config, v1 *viper.Viper)
 	// Avoid recreating these later.
 	v1.Set("allModules", moduleConfig.ActiveModules)
 
-	if len(moduleConfig.ActiveModules) == 0 {
-		return nil, nil, nil
-	}
-
-	var configFilenames []string
-	for _, tc := range moduleConfig.ActiveModules {
-		if tc.ConfigFilename() != "" {
-			if tc.Watch() {
-				configFilenames = append(configFilenames, tc.ConfigFilename())
-			}
-			if err := l.applyThemeConfig(v1, tc); err != nil {
-				return nil, nil, err
-			}
-		}
-	}
-
 	if moduleConfig.GoModulesFilename != "" {
 		// We want to watch this for changes and trigger rebuild on version
 		// changes etc.

hugolib/filesystems/basefs.go

@@ -18,7 +18,6 @@ package filesystems
 import (
 	"io"
 	"os"
-	"path"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -454,7 +453,6 @@ func (b *sourceFilesystemsBuilder) createMainOverlayFs(p *paths.Paths) (*filesys
 	// The theme components are ordered from left to right.
 	// We need to revert it to get the
 	// overlay logic below working as expected, with the project on top (last).
-
 	for i, mod := range mods {
 		dir := mod.Dir()
 
@@ -463,11 +461,9 @@ func (b *sourceFilesystemsBuilder) createMainOverlayFs(p *paths.Paths) (*filesys
 		}
 
 		isMainProject := mod.Owner() == nil
-		// TODO(bep) embed mount + move any duplicate/overlap
 		modsReversed[i] = mountsDescriptor{
-			mounts:        mod.Mounts(),
+			Module:        mod,
 			dir:           dir,
-			watch:         mod.Watch(),
 			isMainProject: isMainProject,
 		}
 	}
@@ -500,36 +496,7 @@ func (b *sourceFilesystemsBuilder) createModFs(
 		return paths.AbsPathify(md.dir, path)
 	}
 
-	seen := make(map[string]bool)
-
-	var mounts []modules.Mount
-
-OUTER:
-	for i, mount := range md.mounts {
-		key := path.Join(mount.Lang, mount.Source, mount.Target)
-		if seen[key] {
-			continue
-		}
-		seen[key] = true
-
-		// Prevent overlapping mounts
-		for j, mount2 := range md.mounts {
-			if j == i || mount2.Target != mount.Target {
-				continue
-			}
-			source := mount.Source
-			if !strings.HasSuffix(source, filePathSeparator) {
-				source += filePathSeparator
-			}
-			if strings.HasPrefix(mount2.Source, source) {
-				continue OUTER
-			}
-		}
-
-		mounts = append(mounts, mount)
-	}
-
-	for _, mount := range mounts {
+	for _, mount := range md.Mounts() {
 
 		mountWeight := 1
 		if md.isMainProject {
@@ -540,7 +507,7 @@ OUTER:
 			From: mount.Target,
 			To:   absPathify(mount.Source),
 			Meta: hugofs.FileMeta{
-				"watch":       md.watch,
+				"watch":       md.Watch(),
 				"mountWeight": mountWeight,
 			},
 		}
@@ -703,9 +670,8 @@ func (c *filesystemsCollector) reverseFis(fis []hugofs.FileMetaInfo) {
 }
 
 type mountsDescriptor struct {
-	mounts        []modules.Mount
+	modules.Module
 	dir           string
-	watch         bool // whether this is a candidate for watching in server mode.
 	isMainProject bool
 }