Fix same resource file published more than once

This may still happen, though, in low memory situations or very big sites, but I'm not sure it's worth spending time on fixing that. Writing the same file more than once isn't harmful, the negative effect is the false path warning.
 We may find a way to detect that situation if this becomes a real problem.

Fixes gohugoio#13164

Author: bep

hugofs/rootmapping_fs.go

@@ -311,12 +311,13 @@ func (fs *RootMappingFs) Open(name string) (afero.File, error) {
 
 // Stat returns the os.FileInfo structure describing a given file.  If there is
 // an error, it will be of type *os.PathError.
+// If multiple roots are found, the last one will be used.
 func (fs *RootMappingFs) Stat(name string) (os.FileInfo, error) {
 	fis, err := fs.doStat(name)
 	if err != nil {
 		return nil, err
 	}
-	return fis[0], nil
+	return fis[len(fis)-1], nil
 }
 
 type ComponentPath struct {

resources/resource_cache.go

@@ -36,6 +36,11 @@ func newResourceCache(rs *Spec, memCache *dynacache.Cache) *ResourceCache {
 			"/res1",
 			dynacache.OptionsPartition{ClearWhen: dynacache.ClearOnChange, Weight: 40},
 		),
+		cacheResourceFile: dynacache.GetOrCreatePartition[string, resource.Resource](
+			memCache,
+			"/res2",
+			dynacache.OptionsPartition{ClearWhen: dynacache.ClearOnChange, Weight: 40},
+		),
 		CacheResourceRemote: dynacache.GetOrCreatePartition[string, resource.Resource](
 			memCache,
 			"/resr",
@@ -58,6 +63,7 @@ type ResourceCache struct {
 	sync.RWMutex
 
 	cacheResource               *dynacache.Partition[string, resource.Resource]
+	cacheResourceFile           *dynacache.Partition[string, resource.Resource]
 	CacheResourceRemote         *dynacache.Partition[string, resource.Resource]
 	cacheResources              *dynacache.Partition[string, resource.Resources]
 	cacheResourceTransformation *dynacache.Partition[string, *resourceAdapterInner]
@@ -79,6 +85,12 @@ func (c *ResourceCache) GetOrCreate(key string, f func() (resource.Resource, err
 	})
 }
 
+func (c *ResourceCache) GetOrCreateFile(key string, f func() (resource.Resource, error)) (resource.Resource, error) {
+	return c.cacheResourceFile.GetOrCreate(key, func(key string) (resource.Resource, error) {
+		return f()
+	})
+}
+
 func (c *ResourceCache) GetOrCreateResources(key string, f func() (resource.Resources, error)) (resource.Resources, error) {
 	return c.cacheResources.GetOrCreate(key, func(key string) (resource.Resources, error) {
 		return f()

resources/resource_factories/create/create.go

@@ -143,19 +143,7 @@ func (c *Client) Get(pathname string) (resource.Resource, error) {
 			return nil, err
 		}
 
-		meta := fi.(hugofs.FileMetaInfo).Meta()
-		pi := meta.PathInfo
-
-		return c.rs.NewResource(resources.ResourceSourceDescriptor{
-			LazyPublish: true,
-			OpenReadSeekCloser: func() (hugio.ReadSeekCloser, error) {
-				return c.rs.BaseFs.Assets.Fs.Open(filename)
-			},
-			Path:                 pi,
-			GroupIdentity:        pi,
-			TargetPath:           pathname,
-			SourceFilenameOrPath: meta.Filename,
-		})
+		return c.getOrCreateFileResource(fi.(hugofs.FileMetaInfo))
 	})
 }
 
@@ -181,6 +169,23 @@ func (c *Client) GetMatch(pattern string) (resource.Resource, error) {
 	return res[0], err
 }
 
+func (c *Client) getOrCreateFileResource(info hugofs.FileMetaInfo) (resource.Resource, error) {
+	meta := info.Meta()
+	return c.rs.ResourceCache.GetOrCreateFile(filepath.ToSlash(meta.Filename), func() (resource.Resource, error) {
+		return c.rs.NewResource(resources.ResourceSourceDescriptor{
+			LazyPublish: true,
+			OpenReadSeekCloser: func() (hugio.ReadSeekCloser, error) {
+				return meta.Open()
+			},
+			NameNormalized:       meta.PathInfo.Path(),
+			NameOriginal:         meta.PathInfo.Unnormalized().Path(),
+			GroupIdentity:        meta.PathInfo,
+			TargetPath:           meta.PathInfo.Unnormalized().Path(),
+			SourceFilenameOrPath: meta.Filename,
+		})
+	})
+}
+
 func (c *Client) match(name, pattern string, matchFunc func(r resource.Resource) bool, firstOnly bool) (resource.Resources, error) {
 	pattern = glob.NormalizePath(pattern)
 	partitions := glob.FilterGlobParts(strings.Split(pattern, "/"))
@@ -191,19 +196,7 @@ func (c *Client) match(name, pattern string, matchFunc func(r resource.Resource)
 		var res resource.Resources
 
 		handle := func(info hugofs.FileMetaInfo) (bool, error) {
-			meta := info.Meta()
-
-			r, err := c.rs.NewResource(resources.ResourceSourceDescriptor{
-				LazyPublish: true,
-				OpenReadSeekCloser: func() (hugio.ReadSeekCloser, error) {
-					return meta.Open()
-				},
-				NameNormalized:       meta.PathInfo.Path(),
-				NameOriginal:         meta.PathInfo.Unnormalized().Path(),
-				GroupIdentity:        meta.PathInfo,
-				TargetPath:           meta.PathInfo.Unnormalized().Path(),
-				SourceFilenameOrPath: meta.Filename,
-			})
+			r, err := c.getOrCreateFileResource(info)
 			if err != nil {
 				return true, err
 			}

testscripts/commands/hugo__path-warnings_issue13164.txt

@@ -0,0 +1,15 @@
+hugo --printPathWarnings
+
+! stderr 'Duplicate target paths'
+
+-- hugo.toml --
+disableKinds = ['page','rss','section','sitemap','taxonomy','term']
+-- assets/foo.txt --
+foo
+-- layouts/index.html --
+A: {{ (resources.Get "foo.txt").RelPermalink }}
+B: {{ (resources.GetMatch "foo.txt").RelPermalink }}
+C: {{ (index (resources.Match "foo.txt") 0).RelPermalink }}
+D: {{ (index (resources.ByType "text") 0).RelPermalink }}
+-- layouts/unused/single.html --
+{{ .Title }}