#255 empty String in attribute value does not remove the attribute

casid · Aug 2, 2023 · 3e4c084 · 3e4c084
1 parent ebb6ba2
commit 3e4c084
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Showing 4 changed files with 17 additions and 4 deletions.
diff --git a/DOCUMENTATION.md b/DOCUMENTATION.md
@@ -317,7 +317,7 @@ For rendering HTML documents, `ContentType.Html` is highly recommended for [secu
 
 ### Smart Attributes
 
-Expressions in HTML attributes are evaluated, so that optimal output is generated. This means attributes with a single output that evaluates to an empty string, null, or false, are not rendered. For instance:
+Expressions in HTML attributes are evaluated, so that optimal output is generated. This means attributes with a single output that evaluates to null, or false, are not rendered. For instance:
 
 ```html
 <span data-title="${null}">Info</span>

diff --git a/jte-kotlin/src/test/java/gg/jte/kotlin/TemplateEngine_HtmlOutputEscapingTest.java b/jte-kotlin/src/test/java/gg/jte/kotlin/TemplateEngine_HtmlOutputEscapingTest.java
@@ -470,7 +470,7 @@ void attributes_String_empty() {
 
         templateEngine.render("template.kte", "", output);
 
-        assertThat(output.toString()).isEqualTo("<button>Click</button>");
+        assertThat(output.toString()).isEqualTo("<button data-value=\"\">Click</button>");
     }
 
     @Test

diff --git a/jte-runtime/src/main/java/gg/jte/runtime/TemplateUtils.java b/jte-runtime/src/main/java/gg/jte/runtime/TemplateUtils.java
@@ -53,7 +53,7 @@ public static boolean isAttributeRendered(double value) {
     }
 
     public static boolean isAttributeRendered(String value) {
-        return value != null && !value.isEmpty();
+        return value != null;
     }
 
     public static boolean isAttributeRendered(Content value) {

diff --git a/jte/src/test/java/gg/jte/TemplateEngine_HtmlOutputEscapingTest.java b/jte/src/test/java/gg/jte/TemplateEngine_HtmlOutputEscapingTest.java
@@ -477,7 +477,20 @@ void attributes_String_empty() {
 
         templateEngine.render("template.jte", "", output);
 
-        assertThat(output.toString()).isEqualTo("<button>Click</button>");
+        assertThat(output.toString()).isEqualTo("<button data-value=\"\">Click</button>");
+    }
+
+    /**
+     * This is essentially the same test as gg.jte.TemplateEngine_HtmlOutputEscapingTest#attributes_String_empty()
+     * But it especially shows that there is a semantic difference between an empty String and null.
+     */
+    @Test
+    void attributes_String_empty_option() {
+        codeResolver.givenCode("template.jte", "@param String value\n<option value=\"${value}\">Empty</option>");
+
+        templateEngine.render("template.jte", "", output);
+
+        assertThat(output.toString()).isEqualTo("<option value=\"\">Empty</option>");
     }
 
     @Test