GetTerms: runtime error: invalid memory address or nil pointer dereference

[earthboundkid]

Bug: If a page doesn't have its taxonomy set, .GetTerms panics.

Workaround (e.g. for topic):

{{ $topics := slice }}
{{ if .Param "topics" }}
  {{  $topic = .GetTerms "topics" }}
{{ end }}

What version of Hugo are you using (hugo version)?

Hugo Static Site Generator v0.67.1/extended darwin/amd64 BuildDate: unknown

Does this issue reproduce with the latest release?

Yes.

[bep]

I tried to create a failing test for this, but failed ... So there must be something I don't understand.

[earthboundkid]

Hmm, it definitely happens on my site, but I am having trouble reproducing it as a Hugo test. Maybe it's because I'm using non-standard taxonomies?

[earthboundkid]

If you checkout spotlightpa/poor-richard@f89ff87#diff-5725f8ca9fd37c1438a052e56a003075 and change

{{ $topic := "" }}
{{ if .Param "topics" }}
  {{  $topic = index (.GetTerms "topics") 0 }}
{{ end }}

to

{{ $topic := index (.GetTerms "topics" | default slice) 0 }}

You get:

ERROR 2020/03/16 16:03:04 Render of "404" failed: execute of template failed: template: 404.html:56:5: executing "404.html" at <partial "ld-json.html" .>: error calling partial: execute of template failed: template: partials/ld-json.html:17:14: executing "partials/ld-json.html" at <partialCached "page-params.html" .Page .RelPermalink>: error calling partialCached: "/Users/cjohnson/src/github/poor-richard/layouts/partials/page-params.html:11:20": execute of template failed: template: partials/page-params.html:11:20: executing "partials/page-params.html" at <.GetTerms>: error calling GetTerms: runtime error: invalid memory address or nil pointer dereference

[earthboundkid]

I think I've figured out how to reproduce it. The 404.html layout needs to be defined and reference .GetTerms.

[earthboundkid]

diff --git a/hugolib/taxonomy_test.go b/hugolib/taxonomy_test.go
index f8dca6a1..52ad6a48 100644
--- a/hugolib/taxonomy_test.go
+++ b/hugolib/taxonomy_test.go
@@ -320,7 +320,7 @@ categories: ["This is Cool", "And new" ]
 ---
 
 Content.
-		
+
 		`)
 	}
 
@@ -535,7 +535,7 @@ Funny:|/p2/|`)
 func TestTaxonomiesListPages(t *testing.T) {
 	b := newTestSitesBuilder(t)
 	b.WithTemplates("_default/list.html", `
-	
+
 {{ template "print-taxo" "categories.cats" }}
 {{ template "print-taxo" "categories.funny" }}
 
@@ -570,7 +570,7 @@ categories: ["cats"]
 	b.Build(BuildCfg{})
 
 	b.AssertFileContent("public/index.html", `
-    
+
 Len categories.cats: 2
 categories.cats:|/blog/|
 categories.cats:|/|
@@ -625,7 +625,9 @@ Category Paginator {{ range $categories.Paginator.Pages }}{{ .RelPermalink }}|{{
 Cats Paginator {{ range $cats.Paginator.Pages }}{{ .RelPermalink }}|{{ end }}:END
 
 `)
-
+	b.WithTemplatesAdded("404.html", `
+404 Terms: {{ range .GetTerms "categories" }}{{.RelPermalink }}|{{ end }}:END
+	`)
 	b.Build(BuildCfg{})
 
 	cat := b.GetPage("categories")
@@ -647,7 +649,7 @@ Home Terms: /categories/dogs/|/categories/gorillas/|:END
 Cats Paginator /section/p1/|/section/|:END
 Category Paginator /categories/birds/|/categories/cats/|/categories/dogs/|/categories/funny/|/categories/gorillas/|:END
 `)
-
+	b.AssertFileContent("public/404.html", "xxx")
 	b.AssertFileContent("public/categories/funny/index.xml", `<link>http://example.com/section/p1/</link>`)
 	b.AssertFileContent("public/categories/index.xml", `<link>http://example.com/categories/funny/</link>`)
 

$ go test . -run TestTaxonomiesPageCollections -v
=== RUN   TestTaxonomiesPageCollections
=== PAUSE TestTaxonomiesPageCollections
=== CONT  TestTaxonomiesPageCollections
github.com/gohugoio/hugo/hugolib.(*Site).renderForTemplate
        /tmp/hugo/hugolib/site.go:1667
github.com/gohugoio/hugo/hugolib.(*Site).renderAndWritePage
        /tmp/hugo/hugolib/site.go:1593
github.com/gohugoio/hugo/hugolib.(*Site).render404
        /tmp/hugo/hugolib/site_render.go:258
github.com/gohugoio/hugo/hugolib.(*Site).render
        /tmp/hugo/hugolib/site.go:1167
github.com/gohugoio/hugo/hugolib.(*HugoSites).render
        /tmp/hugo/hugolib/hugo_sites_build.go:305
github.com/gohugoio/hugo/hugolib.(*HugoSites).Build.func4
        /tmp/hugo/hugolib/hugo_sites_build.go:133
runtime/trace.WithRegion
        /usr/local/Cellar/go/1.14/libexec/src/runtime/trace/annotation.go:137
github.com/gohugoio/hugo/hugolib.(*HugoSites).Build
        /tmp/hugo/hugolib/hugo_sites_build.go:135
github.com/gohugoio/hugo/hugolib.(*sitesBuilder).build
        /tmp/hugo/hugolib/testhelpers_test.go:598
github.com/gohugoio/hugo/hugolib.(*sitesBuilder).Build
        /tmp/hugo/hugolib/testhelpers_test.go:560
github.com/gohugoio/hugo/hugolib.TestTaxonomiesPageCollections
        /tmp/hugo/hugolib/taxonomy_test.go:631
testing.tRunner
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992
runtime.goexit
        /usr/local/Cellar/go/1.14/libexec/src/runtime/asm_amd64.s:1373
    TestTaxonomiesPageCollections: taxonomy_test.go:631: Build failed: render of "404" failed: "layouts/404.html:2:20": execute of template failed: template: 404.html:2:20: executing "404.html" at <.GetTerms>: error calling GetTerms: runtime error: invalid memory address or nil pointer dereference
--- FAIL: TestTaxonomiesPageCollections (0.01s)

[earthboundkid]

In self = p.treeRef.key, treeRef is nil. I don't know enough about Hugo internals to know what this means, but seems like the quick fix is to say if nil, self = ""?

[github-actions]

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