modules: Do not fail build on errors in theme.toml

Fixes #6162

hugolib/hugo_modules_test.go

@@ -349,7 +349,8 @@ path="ok"
 path="incompat1"
 [[module.imports]]
 path="incompat2"
-
+[[module.imports]]
+path="incompat3"
 
 `)
 
@@ -368,6 +369,12 @@ max = "0.45.0"
 	b.WithSourceFile("themes/incompat2/theme.toml", `
 min_version = "5.0.0"
 
+`)
+
+	// Issue 6162
+	b.WithSourceFile("themes/incompat3/theme.toml", `
+min_version = 0.55.0
+
 `)
 
 	logger := loggers.NewWarningLogger()
@@ -377,7 +384,7 @@ min_version = "5.0.0"
 
 	c := qt.New(t)
 
-	c.Assert(logger.WarnCounter.Count(), qt.Equals, uint64(2))
+	c.Assert(logger.WarnCounter.Count(), qt.Equals, uint64(3))
 
 }
 

modules/collect.go

@@ -412,9 +412,10 @@ func (c *collector) applyThemeConfig(tc *moduleAdapter) error {
 		}
 		themeCfg, err = metadecoders.Default.UnmarshalToMap(data, metadecoders.TOML)
 		if err != nil {
-			return errors.Wrapf(err, "failed to read module config for %q in %q", tc.Path(), themeTOML)
+			c.logger.WARN.Printf("Failed to read module config for %q in %q: %s", tc.Path(), themeTOML, err)
+		} else {
+			maps.ToLower(themeCfg)
 		}
-		maps.ToLower(themeCfg)
 	}
 
 	if hasConfig {