Fix case issues with Params

There are currently several Params and case related issues floating around in Hugo.

This is very confusing for users and one of the most common support questions on the forum.

And while there have been done some great leg work in Viper etc., this is of limited value since this and similar doesn't work:

`Params.myCamelCasedParam`

Hugo has control over all the template method invocations, and can take care of all the lower-casing of the map lookup keys.

But that doesn't help with direct template lookups of type `Site.Params.TWITTER_CONFIG.USER_ID`.

This commit solves that by doing some carefully crafted modifications of the templates' AST -- lowercasing the params keys.

This is low-level work, but it's not like the template API wil change -- and this is important enough to defend such "bit fiddling".

Tests are added for all the template engines: Go templates, Ace and Amber.

Fixes #2615
Fixes #1129
Fixes #2590

3 files changed, 295 insertions, 3 deletions

diff --git a/hugolib/case_insensitive_test.go b/hugolib/case_insensitive_test.go
new file mode 100644
index 000000000..01f3f66b5
--- /dev/null
+++ b/hugolib/case_insensitive_test.go
@@ -0,0 +1,289 @@
+// Copyright 2016 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugolib
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+var (
+	caseMixingSiteConfigTOML = `
+Title = "In an Insensitive Mood"
+DefaultContentLanguage = "nn"
+defaultContentLanguageInSubdir = true
+
+[Blackfriday]
+AngledQuotes = true
+HrefTargetBlank = true
+
+[Params]
+Search = true
+Color = "green"
+mood = "Happy"
+[Params.Colors]
+Blue = "blue"
+Yellow = "yellow"
+
+[Languages]
+[Languages.nn]
+title = "Nynorsk title"
+languageName = "Nynorsk"
+weight = 1
+
+[Languages.en]
+TITLE = "English title"
+LanguageName = "English"
+Mood = "Thoughtful"
+Weight = 2
+COLOR = "Pink"
+[Languages.en.blackfriday]
+angledQuotes = false
+hrefTargetBlank = false
+[Languages.en.Colors]
+BLUE = "blues"
+yellow = "golden"
+`
+	caseMixingPage1En = `
+---
+TITLE: Page1 En Translation
+BlackFriday:
+  AngledQuotes: false
+Color: "black"
+Search: true
+mooD: "sad and lonely"
+ColorS: 
+  Blue: "bluesy"
+  Yellow: "sunny"  
+---
+# "Hi"
+{{< shortcode >}}
+`
+
+	caseMixingPage1 = `
+---
+titLe: Side 1
+blackFriday:
+  angledQuotes: true
+color: "red"
+search: false
+MooD: "sad"
+COLORS: 
+  blue: "heavenly"
+  yelloW: "Sunny"  
+---
+# "Hi"
+{{< shortcode >}}
+`
+
+	caseMixingPage2 = `
+---
+TITLE: Page2 Title
+BlackFriday:
+  AngledQuotes: false
+Color: "black"
+search: true
+MooD: "moody"
+ColorS: 
+  Blue: "sky"
+  YELLOW: "flower"  
+---
+# Hi
+{{< shortcode >}}
+`
+)
+
+func caseMixingTestsWriteCommonSources(t *testing.T) {
+	writeSource(t, filepath.Join("content", "sect1", "page1.md"), caseMixingPage1)
+	writeSource(t, filepath.Join("content", "sect2", "page2.md"), caseMixingPage2)
+	writeSource(t, filepath.Join("content", "sect1", "page1.en.md"), caseMixingPage1En)
+
+	writeSource(t, "layouts/shortcodes/shortcode.html", `
+Shortcode Page: {{ .Page.Params.COLOR }}|{{ .Page.Params.Colors.Blue  }}
+Shortcode Site: {{ .Page.Site.Params.COLOR }}|{{ .Site.Params.COLORS.YELLOW  }}
+`)
+
+	writeSource(t, "layouts/partials/partial.html", `
+Partial Page: {{ .Params.COLOR }}|{{ .Params.Colors.Blue }}
+Partial Site: {{ .Site.Params.COLOR }}|{{ .Site.Params.COLORS.YELLOW }}
+`)
+
+	writeSource(t, "config.toml", caseMixingSiteConfigTOML)
+
+}
+
+func TestCaseInsensitiveConfigurationVariations(t *testing.T) {
+	// See issues 2615, 1129, 2590 and maybe some others
+	// Also see 2598
+	//
+	// Viper is now, at least for the Hugo part, case insensitive
+	// So we need tests for all of it, with needed adjustments on the Hugo side.
+	// Not sure what that will be. Let us see.
+
+	// So all the below with case variations:
+	// config: regular fields, blackfriday config, param with nested map
+	// language: new and overridden values, in regular fields and nested paramsmap
+	// page frontmatter: regular fields, blackfriday config, param with nested map
+
+	testCommonResetState()
+	caseMixingTestsWriteCommonSources(t)
+
+	writeSource(t, filepath.Join("layouts", "_default", "baseof.html"), `
+Block Page Colors: {{ .Params.COLOR }}|{{ .Params.Colors.Blue }}	
+{{ block "main" . }}default{{end}}`)
+
+	writeSource(t, filepath.Join("layouts", "sect2", "single.html"), `
+{{ define "main"}}
+Page Colors: {{ .Params.CoLOR }}|{{ .Params.Colors.Blue }}
+Site Colors: {{ .Site.Params.COlOR }}|{{ .Site.Params.COLORS.YELLOW }}
+{{ .Content }}
+{{ partial "partial.html" . }}
+{{ end }}
+`)
+
+	writeSource(t, filepath.Join("layouts", "_default", "single.html"), `
+Page Title: {{ .Title }}
+Site Title: {{ .Site.Title }}
+Site Lang Mood: {{ .Site.Language.Params.MOoD }}
+Page Colors: {{ .Params.COLOR }}|{{ .Params.Colors.Blue }}
+Site Colors: {{ .Site.Params.COLOR }}|{{ .Site.Params.COLORS.YELLOW }}
+{{ .Content }}
+{{ partial "partial.html" . }}
+`)
+
+	if err := LoadGlobalConfig("", "config.toml"); err != nil {
+		t.Fatalf("Failed to load config: %s", err)
+	}
+
+	sites, err := NewHugoSitesFromConfiguration()
+
+	if err != nil {
+		t.Fatalf("Failed to create sites: %s", err)
+	}
+
+	err = sites.Build(BuildCfg{})
+
+	if err != nil {
+		t.Fatalf("Failed to build sites: %s", err)
+	}
+
+	assertFileContent(t, filepath.Join("public", "nn", "sect1", "page1", "index.html"), true,
+		"Page Colors: red|heavenly",
+		"Site Colors: green|yellow",
+		"Site Lang Mood: Happy",
+		"Shortcode Page: red|heavenly",
+		"Shortcode Site: green|yellow",
+		"Partial Page: red|heavenly",
+		"Partial Site: green|yellow",
+		"Page Title: Side 1",
+		"Site Title: Nynorsk title",
+		"&laquo;Hi&raquo;", // angled quotes
+	)
+
+	assertFileContent(t, filepath.Join("public", "en", "sect1", "page1", "index.html"), true,
+		"Site Colors: Pink|golden",
+		"Page Colors: black|bluesy",
+		"Site Lang Mood: Thoughtful",
+		"Page Title: Page1 En Translation",
+		"Site Title: English title",
+		"&ldquo;Hi&rdquo;",
+	)
+
+	assertFileContent(t, filepath.Join("public", "nn", "sect2", "page2", "index.html"), true,
+		"Page Colors: black|sky",
+		"Site Colors: green|yellow",
+		"Shortcode Page: black|sky",
+		"Block Page Colors: black|sky",
+		"Partial Page: black|sky",
+		"Partial Site: green|yellow",
+	)
+}
+
+func TestCaseInsensitiveConfigurationForAllTemplateEngines(t *testing.T) {
+	noOp := func(s string) string {
+		return s
+	}
+
+	amberFixer := func(s string) string {
+		fixed := strings.Replace(s, "{{ .Site.Params", "{{ Site.Params", -1)
+		fixed = strings.Replace(fixed, "{{ .Params", "{{ Params", -1)
+		fixed = strings.Replace(fixed, ".Content", "Content", -1)
+		fixed = strings.Replace(fixed, "{{", "#{", -1)
+		fixed = strings.Replace(fixed, "}}", "}", -1)
+
+		return fixed
+	}
+
+	for _, config := range []struct {
+		suffix        string
+		templateFixer func(s string) string
+	}{
+		{"amber", amberFixer},
+		{"html", noOp},
+		{"ace", noOp},
+	} {
+		doTestCaseInsensitiveConfigurationForTemplateEngine(t, config.suffix, config.templateFixer)
+
+	}
+
+}
+
+func doTestCaseInsensitiveConfigurationForTemplateEngine(t *testing.T, suffix string, templateFixer func(s string) string) {
+
+	testCommonResetState()
+	caseMixingTestsWriteCommonSources(t)
+
+	t.Log("Testing", suffix)
+
+	templTemplate := `
+p
+	|
+	| Page Colors: {{ .Params.CoLOR }}|{{ .Params.Colors.Blue }}
+	| Site Colors: {{ .Site.Params.COlOR }}|{{ .Site.Params.COLORS.YELLOW }}
+	| {{ .Content }}
+
+`
+
+	templ := templateFixer(templTemplate)
+
+	t.Log(templ)
+
+	writeSource(t, filepath.Join("layouts", "_default", fmt.Sprintf("single.%s", suffix)), templ)
+
+	if err := LoadGlobalConfig("", "config.toml"); err != nil {
+		t.Fatalf("Failed to load config: %s", err)
+	}
+
+	sites, err := NewHugoSitesFromConfiguration()
+
+	if err != nil {
+		t.Fatalf("Failed to create sites: %s", err)
+	}
+
+	err = sites.Build(BuildCfg{})
+
+	if err != nil {
+		t.Fatalf("Failed to build sites: %s", err)
+	}
+
+	assertFileContent(t, filepath.Join("public", "nn", "sect1", "page1", "index.html"), true,
+		"Page Colors: red|heavenly",
+		"Site Colors: green|yellow",
+		"Shortcode Page: red|heavenly",
+		"Shortcode Site: green|yellow",
+	)
+
+}
diff --git a/hugolib/page.go b/hugolib/page.go
index de7391599..28792fdc4 100644
--- a/hugolib/page.go
+++ b/hugolib/page.go
@@ -719,6 +719,9 @@ func (p *Page) update(f interface{}) error {
 		return fmt.Errorf("no metadata found")
 	}
 	m := f.(map[string]interface{})
+	// Needed for case insensitive fetching of params values
+	helpers.ToLowerMap(m)
+
 	var err error
 	var draft, published, isCJKLanguage *bool
 	for k, v := range m {
diff --git a/hugolib/site.go b/hugolib/site.go
index fa5f9f2cf..b1c507d89 100644
--- a/hugolib/site.go
+++ b/hugolib/site.go
@@ -1670,7 +1670,7 @@ func (s *Site) renderPages() error {
 
 	err := <-errs
 	if err != nil {
-		return fmt.Errorf("Error(s) rendering pages: %s", err)
+		return fmt.Errorf("Error(s) rendering pages: %.60s…", err)
 	}
 	return nil
 }
@@ -1770,7 +1770,7 @@ func (s *Site) renderTaxonomiesLists(prepare bool) error {
 
 	err := <-errs
 	if err != nil {
-		return fmt.Errorf("Error(s) rendering taxonomies: %s", err)
+		return fmt.Errorf("Error(s) rendering taxonomies: %.60s…", err)
 	}
 	return nil
 }
@@ -2439,7 +2439,7 @@ func (s *Site) renderForLayouts(name string, d interface{}, w io.Writer, layouts
 	if err := s.renderThing(d, layout, w); err != nil {
 
 		// Behavior here should be dependent on if running in server or watch mode.
-		distinctErrorLogger.Printf("Error while rendering %s: %v", name, err)
+		distinctErrorLogger.Printf("Error while rendering %s: %.60s…", name, err)
 		if !s.running() && !testMode {
 			// TODO(bep) check if this can be propagated
 			os.Exit(-1)