Re-add --printUnusedTemplates and --printPathWarnings

And now with tests.

Updates #10953

4 files changed, 59 insertions, 7 deletions

diff --git a/commands/commandeer.go b/commands/commandeer.go
index 465516e2e..222a2a020 100644
--- a/commands/commandeer.go
+++ b/commands/commandeer.go
@@ -115,11 +115,13 @@ type rootCommand struct {
 	environment string
 
 	// Common build flags.
-	baseURL         string
-	gc              bool
-	poll            string
-	panicOnWarning  bool
-	forceSyncStatic bool
+	baseURL              string
+	gc                   bool
+	poll                 string
+	panicOnWarning       bool
+	forceSyncStatic      bool
+	printPathWarnings    bool
+	printUnusedTemplates bool
 
 	// Profile flags (for debugging of performance problems)
 	cpuprofile   string
@@ -538,8 +540,8 @@ func applyLocalBuildFlags(cmd *cobra.Command, r *rootCommand) {
 	cmd.Flags().BoolP("noChmod", "", false, "don't sync permission mode of files")
 	cmd.Flags().BoolP("noBuildLock", "", false, "don't create .hugo_build.lock file")
 	cmd.Flags().BoolP("printI18nWarnings", "", false, "print missing translations")
-	cmd.Flags().BoolP("printPathWarnings", "", false, "print warnings on duplicate target paths etc.")
-	cmd.Flags().BoolP("printUnusedTemplates", "", false, "print warnings on unused templates.")
+	cmd.Flags().BoolVarP(&r.printPathWarnings, "printPathWarnings", "", false, "print warnings on duplicate target paths etc.")
+	cmd.Flags().BoolVarP(&r.printUnusedTemplates, "printUnusedTemplates", "", false, "print warnings on unused templates.")
 	cmd.Flags().StringVarP(&r.cpuprofile, "profile-cpu", "", "", "write cpu profile to `file`")
 	cmd.Flags().StringVarP(&r.memprofile, "profile-mem", "", "", "write memory profile to `file`")
 	cmd.Flags().BoolVarP(&r.printm, "printMemoryUsage", "", false, "print memory usage to screen at intervals")
diff --git a/commands/hugobuilder.go b/commands/hugobuilder.go
index 28c21a9a7..4f65140a0 100644
--- a/commands/hugobuilder.go
+++ b/commands/hugobuilder.go
@@ -41,7 +41,9 @@ import (
 	"github.com/gohugoio/hugo/hugolib/filesystems"
 	"github.com/gohugoio/hugo/livereload"
 	"github.com/gohugoio/hugo/resources/page"
+	"github.com/gohugoio/hugo/tpl"
 	"github.com/gohugoio/hugo/watcher"
+	"github.com/spf13/afero"
 	"github.com/spf13/fsync"
 	"golang.org/x/sync/errgroup"
 	"golang.org/x/sync/semaphore"
@@ -411,6 +413,26 @@ func (c *hugoBuilder) build() error {
 		if err != nil {
 			return err
 		}
+
+		if c.r.printPathWarnings {
+			hugofs.WalkFilesystems(h.Fs.PublishDir, func(fs afero.Fs) bool {
+				if dfs, ok := fs.(hugofs.DuplicatesReporter); ok {
+					dupes := dfs.ReportDuplicates()
+					if dupes != "" {
+						c.r.logger.Warnln("Duplicate target paths:", dupes)
+					}
+				}
+				return false
+			})
+		}
+
+		if c.r.printUnusedTemplates {
+			unusedTemplates := h.Tmpl().(tpl.UnusedTemplatesProvider).UnusedTemplates()
+			for _, unusedTemplate := range unusedTemplates {
+				c.r.logger.Warnf("Template %s is unused, source file %s", unusedTemplate.Name(), unusedTemplate.Filename())
+			}
+		}
+
 		h.PrintProcessingStats(os.Stdout)
 		c.r.Println()
 	}
diff --git a/testscripts/commands/hugo_printpathwarnings.txt b/testscripts/commands/hugo_printpathwarnings.txt
new file mode 100644
index 000000000..f4c76ebab
--- /dev/null
+++ b/testscripts/commands/hugo_printpathwarnings.txt
@@ -0,0 +1,17 @@
+hugo  --printPathWarnings
+
+stdout 'Duplicate target paths: .index.html \(2\)'
+
+-- hugo.toml --
+disableKinds = ["taxonomy", "term", "RSS", "sitemap", "robotsTXT", "404", "section"]
+baseURL = "https://example.org/"
+-- layouts/_default/single.html --
+Single.
+-- layouts/index.html --
+Home.
+-- content/p1.md --
+---
+title: "P1"
+url: "/"
+---
+
diff --git a/testscripts/commands/hugo_printunusedtemplates.txt b/testscripts/commands/hugo_printunusedtemplates.txt
new file mode 100644
index 000000000..312e4920d
--- /dev/null
+++ b/testscripts/commands/hugo_printunusedtemplates.txt
@@ -0,0 +1,11 @@
+hugo  --printUnusedTemplates
+
+stdout 'Template _default/list.html is unused'
+
+-- hugo.toml --
+disableKinds = ["taxonomy", "term", "RSS", "sitemap", "robotsTXT", "404", "section", "page"]
+baseURL = "https://example.org/"
+-- layouts/index.html --
+Home.
+-- layouts/_default/list.html --
+{{ errorf "unused template: %s" .Kind }}