Merge pull request #2511 from technosophos/fix/2452-predictable-template-order

fix(2452): sort templates before parse

pkg/engine/engine.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"fmt"
 	"path"
+	"sort"
 	"strings"
 	"text/template"
 
@@ -181,8 +182,14 @@ func (e *Engine) render(tpls map[string]renderable) (map[string]string, error) {
 
 	funcMap := e.alterFuncMap(t)
 
+	// We want to parse the templates in a predictable order. The order favors
+	// higher-level (in file system) templates over deeply nested templates.
+	keys := sortTemplates(tpls)
+
 	files := []string{}
-	for fname, r := range tpls {
+	//for fname, r := range tpls {
+	for _, fname := range keys {
+		r := tpls[fname]
 		t = t.New(fname).Funcs(funcMap)
 		if _, err := t.Parse(r.tpl); err != nil {
 			return map[string]string{}, fmt.Errorf("parse error in %q: %s", fname, err)
@@ -215,6 +222,30 @@ func (e *Engine) render(tpls map[string]renderable) (map[string]string, error) {
 	return rendered, nil
 }
 
+func sortTemplates(tpls map[string]renderable) []string {
+	keys := make([]string, len(tpls))
+	i := 0
+	for key := range tpls {
+		keys[i] = key
+		i++
+	}
+	sort.Sort(sort.Reverse(byPathLen(keys)))
+	return keys
+}
+
+type byPathLen []string
+
+func (p byPathLen) Len() int      { return len(p) }
+func (p byPathLen) Swap(i, j int) { p[j], p[i] = p[i], p[j] }
+func (p byPathLen) Less(i, j int) bool {
+	a, b := p[i], p[j]
+	ca, cb := strings.Count(a, "/"), strings.Count(b, "/")
+	if ca == cb {
+		return strings.Compare(a, b) == -1
+	}
+	return ca < cb
+}
+
 // allTemplates returns all templates for a chart and its dependencies.
 //
 // As it goes, it also prepares the values in a scope-sensitive manner.

pkg/engine/engine_test.go

@@ -27,6 +27,37 @@ import (
 	"github.com/golang/protobuf/ptypes/any"
 )
 
+func TestSortTemplates(t *testing.T) {
+	tpls := map[string]renderable{
+		"/mychart/templates/foo.tpl":                                 {},
+		"/mychart/templates/charts/foo/charts/bar/templates/foo.tpl": {},
+		"/mychart/templates/bar.tpl":                                 {},
+		"/mychart/templates/charts/foo/templates/bar.tpl":            {},
+		"/mychart/templates/_foo.tpl":                                {},
+		"/mychart/templates/charts/foo/templates/foo.tpl":            {},
+		"/mychart/templates/charts/bar/templates/foo.tpl":            {},
+	}
+	got := sortTemplates(tpls)
+	if len(got) != len(tpls) {
+		t.Fatal("Sorted results are missing templates")
+	}
+
+	expect := []string{
+		"/mychart/templates/charts/foo/charts/bar/templates/foo.tpl",
+		"/mychart/templates/charts/foo/templates/foo.tpl",
+		"/mychart/templates/charts/foo/templates/bar.tpl",
+		"/mychart/templates/charts/bar/templates/foo.tpl",
+		"/mychart/templates/foo.tpl",
+		"/mychart/templates/bar.tpl",
+		"/mychart/templates/_foo.tpl",
+	}
+	for i, e := range expect {
+		if got[i] != e {
+			t.Errorf("expected %q, got %q at index %d\n\tExp: %#v\n\tGot: %#v", e, got[i], i, expect, got)
+		}
+	}
+}
+
 func TestEngine(t *testing.T) {
 	e := New()