Qute: improve the key/property/method "not found" error message

- which may occur at runtime

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/PropertyNotFoundDevModeTest.java

@@ -27,7 +27,7 @@ public class PropertyNotFoundDevModeTest {
     @Test
     public void testExceptionIsThrown() {
         assertEquals(
-                "Rendering error in template [foo.html] line 1: Entry \"foo\" not found in the data map in expression {foo.surname}",
+                "Rendering error in template [foo.html] line 1: Key \"foo\" not found in the template data map with keys [] in expression {foo.surname}",
                 RestAssured.get("test-foo").then().statusCode(200).extract().body().asString());
         assertEquals(
                 "Rendering error in template [bar.html] line 1: Property \"name\" not found on the base object \"java.lang.String\" in expression {bar.name}",

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/extensions/TimeTemplateExtensionsTest.java

@@ -59,7 +59,8 @@ public void testInvalidParameter() {
             engine.parse("{time:format(input.birthday, 'uuuu')}").data("input", Map.of("name", "Quarkus Qute")).render();
             fail();
         } catch (TemplateException expected) {
-            assertTrue(expected.getMessage().startsWith("Rendering error: Property \"birthday\" not found on the base object"),
+            assertTrue(
+                    expected.getMessage().startsWith("Rendering error: Key \"birthday\" not found in the map with keys [name]"),
                     expected.getMessage());
         }
     }

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/propertynotfound/PropertyNotFoundThrowExceptionTest.java

@@ -36,7 +36,8 @@ public void testException() {
         } catch (Exception expected) {
             Throwable rootCause = ExceptionUtil.getRootCause(expected);
             assertEquals(TemplateException.class, rootCause.getClass());
-            assertTrue(rootCause.getMessage().contains("Entry \"foos\" not found in the data map"), rootCause.getMessage());
+            assertTrue(rootCause.getMessage().contains("Key \"foos\" not found in the template data map with keys []"),
+                    rootCause.getMessage());
         }
     }
 

independent-projects/qute/core/src/main/java/io/quarkus/qute/LoopSectionHelper.java

@@ -12,6 +12,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.CompletionStage;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
@@ -317,6 +318,18 @@ public CompletionStage<Object> getAsync(String key) {
             }
         }
 
+        @Override
+        public Set<String> mappedKeys() {
+            if (metadataPrefix != null) {
+                return Set.of(alias, metadataPrefix + "count", metadataPrefix + "index", metadataPrefix + "indexParity",
+                        metadataPrefix + "hasNext", metadataPrefix + "isLast", metadataPrefix + "isFirst",
+                        metadataPrefix + "isOdd", metadataPrefix + "odd", metadataPrefix + "isEven", metadataPrefix + "even");
+            } else {
+                return Set.of(alias, "count", "index", "indexParity", "hasNext", "isLast", "isFirst", "isOdd",
+                        "odd", "isEven", "even");
+            }
+        }
+
     }
 
     enum Code implements ErrorCode {

independent-projects/qute/core/src/main/java/io/quarkus/qute/Mapper.java

@@ -1,6 +1,7 @@
 package io.quarkus.qute;
 
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.CompletionStage;
 
 /**
@@ -28,24 +29,22 @@ default boolean appliesTo(String key) {
         return true;
     }
 
+    /**
+     * The returned set may be a subset of the final set of all mapped keys.
+     *
+     * @return the set of known mapped keys
+     */
+    default Set<String> mappedKeys() {
+        return Set.of();
+    }
+
     /**
      *
      * @param map
      * @return a mapper that wraps the given map
      */
     static Mapper wrap(Map<String, ?> map) {
-        return new Mapper() {
-
-            @Override
-            public boolean appliesTo(String key) {
-                return map.containsKey(key);
-            }
-
-            @Override
-            public Object get(String key) {
-                return map.get(key);
-            }
-        };
+        return new MapperMapWrapper(map);
     }
 
 }

independent-projects/qute/core/src/main/java/io/quarkus/qute/MapperMapWrapper.java

@@ -0,0 +1,29 @@
+package io.quarkus.qute;
+
+import java.util.Map;
+import java.util.Set;
+
+final class MapperMapWrapper implements Mapper {
+
+    private final Map<String, ?> map;
+
+    MapperMapWrapper(Map<String, ?> map) {
+        this.map = map;
+    }
+
+    @Override
+    public boolean appliesTo(String key) {
+        return map.containsKey(key);
+    }
+
+    @Override
+    public Object get(String key) {
+        return map.get(key);
+    }
+
+    @Override
+    public Set<String> mappedKeys() {
+        return map.keySet();
+    }
+
+}

independent-projects/qute/core/src/main/java/io/quarkus/qute/Results.java

@@ -1,5 +1,7 @@
 package io.quarkus.qute;
 
+import static java.util.function.Predicate.not;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -135,29 +137,49 @@ public String asMessage() {
             if (name != null) {
                 Object base = getBase().orElse(null);
                 List<Expression> params = getParams();
-                boolean isDataMap = isDataMap(base);
-                // Entry "foo" not found in the data map
-                // Property "foo" not found on base object "org.acme.Bar"
-                // Method "getDiscount(value)" not found on base object "org.acme.Item"
                 StringBuilder builder = new StringBuilder();
-                if (isDataMap) {
-                    builder.append("Entry ");
-                } else if (params.isEmpty()) {
-                    builder.append("Property ");
-                } else {
-                    builder.append("Method ");
-                }
-                builder.append("\"").append(name);
-                if (!params.isEmpty()) {
-                    builder.append("(");
-                    builder.append(params.stream().map(Expression::toOriginalString).collect(Collectors.joining(",")));
-                    builder.append(")");
-                }
-                builder.append("\" not found");
-                if (isDataMap) {
-                    builder.append(" in the data map");
+                if (base instanceof Map || base instanceof Mapper) {
+                    builder.append("Key ")
+                            .append("\"")
+                            .append(name)
+                            .append("\" not found in the");
+                    if (isDataMap(base)) {
+                        // Key "foo" not found in the template data map with keys []
+                        builder.append(" template data map with keys ");
+                        if (base instanceof Map) {
+                            builder.append(((Map<?, ?>) base).keySet().stream()
+                                    .filter(not(TemplateInstanceBase.DATA_MAP_KEY::equals)).collect(Collectors.toList()));
+                        } else if (base instanceof Mapper) {
+                            builder.append(((Mapper) base).mappedKeys().stream()
+                                    .filter(not(TemplateInstanceBase.DATA_MAP_KEY::equals)).collect(Collectors.toList()));
+                        }
+                    } else {
+                        // Key "foo" not found in the map with keys []
+                        builder.append(" map with keys ");
+                        if (base instanceof Map) {
+                            builder.append(((Map<?, ?>) base).keySet());
+                        } else if (base instanceof Mapper) {
+                            builder.append(((Mapper) base).mappedKeys());
+                        }
+                    }
+                } else if (!params.isEmpty()) {
+                    // Method "getDiscount(value)" not found on the base object "org.acme.Item"
+                    builder.append("Method ")
+                            .append("\"")
+                            .append(name)
+                            .append("(")
+                            .append(params.stream().map(Expression::toOriginalString).collect(Collectors.joining(",")))
+                            .append(")")
+                            .append("\" not found")
+                            .append(" on the base object \"").append(base == null ? "null" : base.getClass().getName())
+                            .append("\"");
                 } else {
-                    builder.append(" on the base object \"").append(base == null ? "null" : base.getClass().getName())
+                    // Property "foo" not found on the base object "org.acme.Bar"
+                    builder.append("Property ")
+                            .append("\"")
+                            .append(name)
+                            .append("\" not found")
+                            .append(" on the base object \"").append(base == null ? "null" : base.getClass().getName())
                             .append("\"");
                 }
                 return builder.toString();

independent-projects/qute/core/src/test/java/io/quarkus/qute/IfSectionTest.java

@@ -221,7 +221,8 @@ public void testSafeExpression() {
             engine.parse("{#if val.is.not.there}NOK{#else}OK{/if}").render();
             fail();
         } catch (TemplateException expected) {
-            assertEquals("Rendering error: Entry \"val\" not found in the data map in expression {val.is.not.there}",
+            assertEquals(
+                    "Rendering error: Key \"val\" not found in the template data map with keys [] in expression {val.is.not.there}",
                     expected.getMessage());
         }
         assertEquals("OK", engine.parse("{#if val.is.not.there??}NOK{#else}OK{/if}").render());

independent-projects/qute/core/src/test/java/io/quarkus/qute/NotFoundResultTest.java

@@ -0,0 +1,66 @@
+package io.quarkus.qute;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletionStage;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+import io.quarkus.qute.Results.NotFound;
+
+public class NotFoundResultTest {
+
+    @Test
+    public void testAsMessage() {
+        assertEquals("Key \"foo\" not found in the template data map with keys []",
+                NotFound.from(evalContext(Map.of(TemplateInstanceBase.DATA_MAP_KEY, true))).asMessage());
+        assertEquals("Key \"foo\" not found in the map with keys [baz]",
+                NotFound.from(evalContext(Map.of("baz", true))).asMessage());
+        assertEquals("Property \"foo\" not found on the base object \"java.lang.Boolean\"",
+                NotFound.from(evalContext(Boolean.TRUE)).asMessage());
+        assertEquals("Method \"foo(param)\" not found on the base object \"java.lang.Boolean\"",
+                NotFound.from(evalContext(Boolean.TRUE, "param")).asMessage());
+        assertEquals("Key \"foo\" not found in the map with keys [baz]",
+                NotFound.from(evalContext(Mapper.wrap(Map.of("baz", false)))).asMessage());
+    }
+
+    EvalContext evalContext(Object base, Object... params) {
+        return new EvalContext() {
+
+            @Override
+            public List<Expression> getParams() {
+                return Arrays.stream(params).map(p -> ExpressionImpl.from(p.toString())).collect(Collectors.toList());
+            }
+
+            @Override
+            public String getName() {
+                return "foo";
+            }
+
+            @Override
+            public Object getBase() {
+                return base;
+            }
+
+            @Override
+            public Object getAttribute(String key) {
+                return null;
+            }
+
+            @Override
+            public CompletionStage<Object> evaluate(Expression expression) {
+                return null;
+            }
+
+            @Override
+            public CompletionStage<Object> evaluate(String expression) {
+                return null;
+            }
+        };
+    }
+
+}

independent-projects/qute/core/src/test/java/io/quarkus/qute/SimpleTest.java

@@ -153,7 +153,7 @@ public void testEmptySectionTag() {
 
     @Test
     public void testNotFound() {
-        assertEquals("Entry \"foo\" not found in the data map in foo.bar Collection size: 0",
+        assertEquals("Key \"foo\" not found in the template data map with keys [collection] in foo.bar Collection size: 0",
                 Engine.builder().strictRendering(false).addDefaultValueResolvers()
                         .addResultMapper(new ResultMapper() {
 

independent-projects/qute/core/src/test/java/io/quarkus/qute/WhenSectionTest.java

@@ -59,7 +59,14 @@ public void testSwitchEnum() {
         try {
             fail(template.data("state", null).render());
         } catch (TemplateException expected) {
-            assertEquals("Rendering error: Entry \"ON\" not found in the data map in expression {ON}",
+            // If state is null we can't detect it's an enum value, hence the weird error message
+            assertEquals("Rendering error: Key \"ON\" not found in the template data map with keys [state] in expression {ON}",
+                    expected.getMessage());
+        }
+        try {
+            fail(template.render());
+        } catch (TemplateException expected) {
+            assertEquals("Rendering error: Key \"state\" not found in the template data map with keys [] in expression {state}",
                     expected.getMessage());
         }
     }
@@ -75,7 +82,14 @@ public void testWhenEnum() {
         try {
             fail(template.data("state", null).render());
         } catch (TemplateException expected) {
-            assertEquals("Rendering error: Entry \"ON\" not found in the data map in expression {ON}",
+            // If state is null we can't detect it's an enum value, hence the weird error message
+            assertEquals("Rendering error: Key \"ON\" not found in the template data map with keys [state] in expression {ON}",
+                    expected.getMessage());
+        }
+        try {
+            fail(template.render());
+        } catch (TemplateException expected) {
+            assertEquals("Rendering error: Key \"state\" not found in the template data map with keys [] in expression {state}",
                     expected.getMessage());
         }
     }
@@ -129,7 +143,8 @@ public void testWhenNotFound() {
         try {
             fail(template.render());
         } catch (TemplateException expected) {
-            assertEquals("Rendering error: Entry \"testMe\" not found in the data map in expression {testMe}",
+            assertEquals(
+                    "Rendering error: Key \"testMe\" not found in the template data map with keys [] in expression {testMe}",
                     expected.getMessage());
         }
     }