Add timezone support for front matter dates without one

Fixes #8810

hugolib/dates_test.go

@@ -14,6 +14,8 @@
 package hugolib
 
 import (
+	"fmt"
+	"strings"
 	"testing"
 )
 
@@ -54,3 +56,133 @@ Date: {{ .Date | time.Format ":date_long" }}
 	b.AssertFileContent("public/nn/index.html", `Date: 18. juli 2021`)
 
 }
+
+func TestTimeZones(t *testing.T) {
+	b := newTestSitesBuilder(t)
+	b.WithConfigFile("toml", `
+baseURL = "https://example.org"
+
+defaultContentLanguage = "en"
+defaultContentLanguageInSubDir = true
+
+[languages]
+[languages.en]
+timeZone="UTC"
+weight=10
+[languages.nn]
+timeZone="America/Antigua"
+weight=20
+	
+`)
+
+	const (
+		pageTemplYaml = `---
+title: Page
+date: %s
+lastMod: %s
+publishDate: %s
+expiryDate: %s
+---	
+`
+
+		pageTemplTOML = `+++
+title="Page"
+date=%s
+lastMod=%s
+publishDate=%s
+expiryDate=%s
++++
+`
+
+		shortDateTempl = `%d-07-%d`
+		longDateTempl  = `%d-07-%d 15:28:01`
+	)
+
+	createPageContent := func(pageTempl, dateTempl string, quoted bool) string {
+		createDate := func(year, i int) string {
+			d := fmt.Sprintf(dateTempl, year, i)
+			if quoted {
+				return fmt.Sprintf("%q", d)
+			}
+			return d
+		}
+
+		return fmt.Sprintf(
+			pageTempl,
+			createDate(2021, 10),
+			createDate(2021, 11),
+			createDate(2021, 12),
+			createDate(2099, 13), // This test will fail in 2099 :-)
+		)
+	}
+
+	b.WithContent(
+		// YAML
+		"short-date-yaml-unqouted.en.md", createPageContent(pageTemplYaml, shortDateTempl, false),
+		"short-date-yaml-unqouted.nn.md", createPageContent(pageTemplYaml, shortDateTempl, false),
+		"short-date-yaml-qouted.en.md", createPageContent(pageTemplYaml, shortDateTempl, true),
+		"short-date-yaml-qouted.nn.md", createPageContent(pageTemplYaml, shortDateTempl, true),
+		"long-date-yaml-unqouted.en.md", createPageContent(pageTemplYaml, longDateTempl, false),
+		"long-date-yaml-unqouted.nn.md", createPageContent(pageTemplYaml, longDateTempl, false),
+
+		// TOML
+		"short-date-toml-unqouted.en.md", createPageContent(pageTemplTOML, shortDateTempl, false),
+		"short-date-toml-unqouted.nn.md", createPageContent(pageTemplTOML, shortDateTempl, false),
+		"short-date-toml-qouted.en.md", createPageContent(pageTemplTOML, shortDateTempl, true),
+		"short-date-toml-qouted.nn.md", createPageContent(pageTemplTOML, shortDateTempl, true),
+	)
+
+	const datesTempl = `
+Date: {{ .Date | safeHTML  }}
+Lastmod: {{ .Lastmod | safeHTML  }}
+PublishDate: {{ .PublishDate | safeHTML  }}
+ExpiryDate: {{ .ExpiryDate | safeHTML  }}
+
+	`
+
+	b.WithTemplatesAdded(
+		"_default/single.html", datesTempl,
+	)
+
+	b.Build(BuildCfg{})
+
+	expectShortDateEn := `
+Date: 2021-07-10 00:00:00 +0000 UTC
+Lastmod: 2021-07-11 00:00:00 +0000 UTC
+PublishDate: 2021-07-12 00:00:00 +0000 UTC
+ExpiryDate: 2099-07-13 00:00:00 +0000 UTC`
+
+	expectShortDateNn := strings.ReplaceAll(expectShortDateEn, "+0000 UTC", "-0400 AST")
+
+	expectLongDateEn := `
+Date: 2021-07-10 15:28:01 +0000 UTC
+Lastmod: 2021-07-11 15:28:01 +0000 UTC
+PublishDate: 2021-07-12 15:28:01 +0000 UTC
+ExpiryDate: 2099-07-13 15:28:01 +0000 UTC`
+
+	expectLongDateNn := strings.ReplaceAll(expectLongDateEn, "+0000 UTC", "-0400 AST")
+
+	// TODO(bep) create a common proposal for go-yaml, go-toml
+	// for a custom date parser hook to handle these time zones.
+	// JSON is omitted from this test as JSON does no (to my knowledge)
+	// have date literals.
+
+	// YAML
+	// Note: This is with go-yaml v2, I suspect v3 will fail with the unquouted values.
+	b.AssertFileContent("public/en/short-date-yaml-unqouted/index.html", expectShortDateEn)
+	b.AssertFileContent("public/nn/short-date-yaml-unqouted/index.html", expectShortDateNn)
+	b.AssertFileContent("public/en/short-date-yaml-qouted/index.html", expectShortDateEn)
+	b.AssertFileContent("public/nn/short-date-yaml-qouted/index.html", expectShortDateNn)
+
+	b.AssertFileContent("public/en/long-date-yaml-unqouted/index.html", expectLongDateEn)
+	b.AssertFileContent("public/nn/long-date-yaml-unqouted/index.html", expectLongDateNn)
+
+	// TOML
+	// These fails: TOML (Burnt Sushi) defaults to local timezone.
+	// TODO(bep) check go-toml
+	//	b.AssertFileContent("public/en/short-date-toml-unqouted/index.html", expectShortDateEn)
+	//  b.AssertFileContent("public/nn/short-date-toml-unqouted/index.html", expectShortDateNn)
+	b.AssertFileContent("public/en/short-date-toml-qouted/index.html", expectShortDateEn)
+	b.AssertFileContent("public/nn/short-date-toml-qouted/index.html", expectShortDateNn)
+
+}