Make hugo.toml the new config.toml

Both will of course work, but hugo.toml will win if both are set.

We should have done this a long time ago, of course, but the reason I'm picking this up now is that my VS Code setup by default picks up some
JSON config schema from some random other software which also names its config files config.toml.

Fixes #8979

3 files changed, 89 insertions, 15 deletions

diff --git a/hugolib/config.go b/hugolib/config.go
index 8e73a35ec..059424e85 100644
--- a/hugolib/config.go
+++ b/hugolib/config.go
@@ -69,18 +69,35 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 	// use a partial configuration to do its job.
 	defer l.deleteMergeStrategies()
 
-	for _, name := range d.configFilenames() {
-		var filename string
-		filename, err := l.loadConfig(name)
-		if err == nil {
-			configFiles = append(configFiles, filename)
-		} else if err != ErrNoConfigFile {
-			return nil, nil, l.wrapFileError(err, filename)
+	names := d.configFilenames()
+
+	if names != nil {
+		for _, name := range names {
+			var filename string
+			filename, err := l.loadConfig(name)
+			if err == nil {
+				configFiles = append(configFiles, filename)
+			} else if err != ErrNoConfigFile {
+				return nil, nil, l.wrapFileError(err, filename)
+			}
+		}
+	} else {
+		for _, name := range config.DefaultConfigNames {
+			var filename string
+			filename, err := l.loadConfig(name)
+			if err == nil {
+				configFiles = append(configFiles, filename)
+				break
+			} else if err != ErrNoConfigFile {
+				return nil, nil, l.wrapFileError(err, filename)
+			}
 		}
 	}
 
 	if d.AbsConfigDir != "" {
+
 		dcfg, dirnames, err := config.LoadConfigFromDir(l.Fs, d.AbsConfigDir, l.Environment)
+
 		if err == nil {
 			if len(dirnames) > 0 {
 				l.cfg.Set("", dcfg.Get(""))
@@ -162,9 +179,9 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 	return l.cfg, configFiles, err
 }
 
-// LoadConfigDefault is a convenience method to load the default "config.toml" config.
+// LoadConfigDefault is a convenience method to load the default "hugo.toml" config.
 func LoadConfigDefault(fs afero.Fs) (config.Provider, error) {
-	v, _, err := LoadConfig(ConfigSourceDescriptor{Fs: fs, Filename: "config.toml"})
+	v, _, err := LoadConfig(ConfigSourceDescriptor{Fs: fs})
 	return v, err
 }
 
@@ -202,7 +219,7 @@ func (d ConfigSourceDescriptor) configFileDir() string {
 
 func (d ConfigSourceDescriptor) configFilenames() []string {
 	if d.Filename == "" {
-		return []string{"config"}
+		return nil
 	}
 	return strings.Split(d.Filename, ",")
 }
diff --git a/hugolib/config_test.go b/hugolib/config_test.go
index 882d83c8d..37605b4c2 100644
--- a/hugolib/config_test.go
+++ b/hugolib/config_test.go
@@ -782,3 +782,55 @@ defaultMarkdownHandler = 'blackfriday'
 	b.Assert(err.Error(), qt.Contains, "Configured defaultMarkdownHandler \"blackfriday\" not found. Did you mean to use goldmark? Blackfriday was removed in Hugo v0.100.0.")
 
 }
+
+// Issue 8979
+func TestHugoConfig(t *testing.T) {
+	filesTemplate := `
+-- hugo.toml --
+theme = "mytheme"
+[params]
+rootparam = "rootvalue"
+-- config/_default/hugo.toml --
+[params]
+rootconfigparam = "rootconfigvalue"
+-- themes/mytheme/config/_default/hugo.toml --
+[params]
+themeconfigdirparam = "themeconfigdirvalue"
+-- themes/mytheme/hugo.toml --
+[params]
+themeparam = "themevalue"
+-- layouts/index.html --
+rootparam: {{ site.Params.rootparam }}
+rootconfigparam: {{ site.Params.rootconfigparam }}
+themeparam: {{ site.Params.themeparam }}
+themeconfigdirparam: {{ site.Params.themeconfigdirparam }}
+
+
+`
+
+	for _, configName := range []string{"hugo.toml", "config.toml"} {
+		configName := configName
+		t.Run(configName, func(t *testing.T) {
+			t.Parallel()
+
+			files := strings.ReplaceAll(filesTemplate, "hugo.toml", configName)
+
+			b, err := NewIntegrationTestBuilder(
+				IntegrationTestConfig{
+					T:           t,
+					TxtarString: files,
+				},
+			).BuildE()
+
+			b.Assert(err, qt.IsNil)
+			b.AssertFileContent("public/index.html",
+				"rootparam: rootvalue",
+				"rootconfigparam: rootconfigvalue",
+				"themeparam: themevalue",
+				"themeconfigdirparam: themeconfigdirvalue",
+			)
+
+		})
+	}
+
+}
diff --git a/hugolib/integrationtest_builder.go b/hugolib/integrationtest_builder.go
index 9dcfe4830..5b457893d 100644
--- a/hugolib/integrationtest_builder.go
+++ b/hugolib/integrationtest_builder.go
@@ -301,13 +301,18 @@ func (s *IntegrationTestBuilder) initBuilder() error {
 			s.Assert(afero.WriteFile(afs, filename, data, 0666), qt.IsNil)
 		}
 
+		configDirFilename := filepath.Join(s.Cfg.WorkingDir, "config")
+		if _, err := afs.Stat(configDirFilename); err != nil {
+			configDirFilename = ""
+		}
+
 		cfg, _, err := LoadConfig(
 			ConfigSourceDescriptor{
-				WorkingDir: s.Cfg.WorkingDir,
-				Fs:         afs,
-				Logger:     logger,
-				Environ:    []string{},
-				Filename:   "config.toml",
+				WorkingDir:   s.Cfg.WorkingDir,
+				AbsConfigDir: configDirFilename,
+				Fs:           afs,
+				Logger:       logger,
+				Environ:      []string{},
 			},
 			func(cfg config.Provider) error {
 				return nil