Hugo panic: "template /tags/list.html not parsed"

support
1

I’m editing /layouts/tags (tags.html and terms.html). Whenever I save either file while the Hugo server is running to preview the site, the server crashes with the error shown below.

The crash happens even if the file is empty or contains only a simple “hello”. Any save to tags.html or terms.html inside /layouts/tags causes the server to fail; editing files outside that directory does not trigger the issue.

This started today, it may be related to the 0.160.0 update. Any advice would be appreciated. Thank you.

Change detected, rebuilding site (#1).
2026-04-08 03:33:52.059 +0100
Template changed /tags/list.html
Web Server is available at //localhost:1313/ (bind address 127.0.0.1)
Total in 3 ms
panic: template /tags/list.html not parsed

goroutine 52 [running]:
github.com/gohugoio/hugo/tpl/tplimpl.applyTemplateTransformers(0x29227ba0c140, 0x29227c020408, 0x3395230)
        github.com/gohugoio/hugo/tpl/tplimpl/templatetransform.go:84 +0x2d3
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates-range1(0x29227ba0c140)
        github.com/gohugoio/hugo/tpl/tplimpl/templatestore.go:1918 +0x97
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates.(*TemplateStore).transformTemplates.(*TemplateStore).templates.func2-range2({0x1?, 0x29227b6926a0?}, 0x10cb7e5?)
        github.com/gohugoio/hugo/tpl/tplimpl/templatestore.go:1765 +0xb5
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates.(*TemplateStore).transformTemplates.(*TemplateStore).templates.func2.(*TemplateStore).transformTemplates.(*TemplateStore).transformTemplates.(*TemplateStore).templates.func2.(*SimpleTree[...]).All.func3.func4(0xa?)
        github.com/gohugoio/hugo/hugolib/doctree/simpletree.go:111 +0x28
github.com/gohugoio/go-radix.WalkFn[...].Handle(...)
        github.com/gohugoio/go-radix@v1.2.0/radix.go:43
github.com/gohugoio/go-radix.recursiveWalk[...](0x29227c302420, {0x33d9970, 0x29227bae6280})
        github.com/gohugoio/go-radix@v1.2.0/radix.go:604 +0x85
github.com/gohugoio/go-radix.recursiveWalk[...](0x29227c1775c0, {0x33d9970, 0x29227bae6280})
        github.com/gohugoio/go-radix@v1.2.0/radix.go:622 +0x156
github.com/gohugoio/go-radix.recursiveWalk[...](0x29227c176330, {0x33d9970, 0x29227bae6280})
        github.com/gohugoio/go-radix@v1.2.0/radix.go:622 +0x156
github.com/gohugoio/go-radix.(*Tree[...]).Walk(...)
        github.com/gohugoio/go-radix@v1.2.0/radix.go:504
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates.(*TemplateStore).transformTemplates.(*TemplateStore).templates.func2.(*SimpleTree[...]).All.func3(...)
        github.com/gohugoio/hugo/hugolib/doctree/simpletree.go:116
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates.(*TemplateStore).templates.func2(...)
        github.com/gohugoio/hugo/tpl/tplimpl/templatestore.go:1756
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).transformTemplates(0x29227c020408)
        github.com/gohugoio/hugo/tpl/tplimpl/templatestore.go:1910 +0x1bf
github.com/gohugoio/hugo/tpl/tplimpl.(*TemplateStore).RefreshFiles(0x29227c020408, 0x29227c368ab0)
        github.com/gohugoio/hugo/tpl/tplimpl/templatestore.go:750 +0xbb
github.com/gohugoio/hugo/hugolib.(*HugoSites).processPartialFileEvents.func7()
        github.com/gohugoio/hugo/hugolib/hugo_sites_build.go:1199 +0x16c
github.com/gohugoio/hugo/common/loggers.TimeTrackfn(0x29227b693190)
        github.com/gohugoio/hugo/common/loggers/logger.go:394 +0x35
github.com/gohugoio/hugo/hugolib.(*HugoSites).processPartialFileEvents(0x29227c051d48, {0x33f04e0, 0x575a500}, {0x3407d70, 0x29227b96c480}, 0x29227b627280, 0x29227b693558, {0x29227c300550, 0x1, 0x2})
        github.com/gohugoio/hugo/hugolib/hugo_sites_build.go:1195 +0x20b0
github.com/gohugoio/hugo/hugolib.(*HugoSites).process(0x29227c051d48, {0x33f04e0, 0x575a500}, {0x3407d70?, 0x29227b96c480?}, 0x29227b627280, 0x29227d997558, {0x29227c300550, 0x1, 0x2})
        github.com/gohugoio/hugo/hugolib/hugo_sites_build.go:288 +0x265
github.com/gohugoio/hugo/hugolib.(*HugoSites).Build.func6(...)
        github.com/gohugoio/hugo/hugolib/hugo_sites_build.go:170
github.com/gohugoio/hugo/hugolib.(*HugoSites).Build(0x29227c051d48, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0}, {0x29227c300550, ...})
        github.com/gohugoio/hugo/hugolib/hugo_sites_build.go:186 +0x831
github.com/gohugoio/hugo/commands.(*hugoBuilder).rebuildSites(0x29227bfeb080, {0x29227c300550, 0x1, 0x2})
        github.com/gohugoio/hugo/commands/hugobuilder.go:1160 +0x1ed
github.com/gohugoio/hugo/commands.(*hugoBuilder).handleEvents.func7(0x29227bfeb080, 0x29227c32e078)
        github.com/gohugoio/hugo/commands/hugobuilder.go:949 +0x79
github.com/gohugoio/hugo/commands.(*hugoBuilder).handleEvents(0x29227bfeb080, 0x29227c481b30, 0x29227bb05f58, {0x29227c300370, 0x2, 0x2}, 0x29227c4afec0)
        github.com/gohugoio/hugo/commands/hugobuilder.go:952 +0x1b85
github.com/gohugoio/hugo/commands.(*hugoBuilder).newWatcher.func2()
        github.com/gohugoio/hugo/commands/hugobuilder.go:393 +0x2aa
created by github.com/gohugoio/hugo/commands.(*hugoBuilder).newWatcher in goroutine 1
        github.com/gohugoio/hugo/commands/hugobuilder.go:364 +0x4d4
2

I don’t see a change in 0.160 related to this, but I will check

4

It looks like your changes to fix this issue will be included in a future Hugo release, correct? I noticed you described this approach as “legacy” on the GitHub issue; is there a better way to accomplish what I’m trying to do? Thanks.

5

This was fixed in Release v0.160.1 · gohugoio/hugo · GitHub

So, the technical reason behind this panic was the legacy mapping we did to preserve old and new syntax when we redid that strucure in v0.146.0, see New template system in Hugo v0.146.0

Your layouts/tags/list.html matched one of the legacy rules, but it was also valid in the new setup, hence the breakage.

I would say that your setup is fine, but it’s rare enough that we have not seen this panic before.