Return the expected output

In if-else expressions, return the output of the executed branch
rather than the input. The current behavior was undocumented and
quite unexpected, so I suggest we treat that as a bug.

Also return the last executed expression in a script as its
output (rather than nothing.

In addition, improve some error messages.

6 files changed, 84 insertions, 25 deletions

diff --git a/config-model/src/main/java/com/yahoo/schema/document/SDField.java b/config-model/src/main/java/com/yahoo/schema/document/SDField.java
index 7821c101880..6cbdb38b9bc 100644
--- a/config-model/src/main/java/com/yahoo/schema/document/SDField.java
+++ b/config-model/src/main/java/com/yahoo/schema/document/SDField.java
@@ -196,6 +196,8 @@ public class SDField extends Field implements TypedKey, ImmutableSDField {
         return isExtraField;
     }
 
+    public boolean isDocumentField() { return ! isExtraField; }
+
     @Override
     public boolean isImportedField() {
         return false;
@@ -613,11 +615,8 @@ public class SDField extends Field implements TypedKey, ImmutableSDField {
     @Override
     public RankType getRankType() { return this.rankType; }
 
-    /**
-     * Returns the search-time attribute settings of this field or null if none is set.
-     *
-     * <p>TODO: Make unmodifiable.</p>
-     */
+    /** Returns the search-time attribute settings of this field or null if none is set. */
+     // TODO: Make unmodifiable
     @Override
     public Map<String, Attribute> getAttributes() { return attributes; }
 
diff --git a/config-model/src/main/java/com/yahoo/schema/processing/IndexingInputs.java b/config-model/src/main/java/com/yahoo/schema/processing/IndexingInputs.java
index 985ec8653c7..0537f1704ab 100644
--- a/config-model/src/main/java/com/yahoo/schema/processing/IndexingInputs.java
+++ b/config-model/src/main/java/com/yahoo/schema/processing/IndexingInputs.java
@@ -31,9 +31,8 @@ public class IndexingInputs extends Processor {
             ScriptExpression script = field.getIndexingScript();
             if (script == null) continue;
 
-            String fieldName = field.getName();
-            script = (ScriptExpression)new DefaultToCurrentField(fieldName).convert(script);
-            script = (ScriptExpression)new EnsureInputExpression(fieldName).convert(script);
+            script = (ScriptExpression)new DefaultToCurrentField(field).convert(script);
+            script = (ScriptExpression)new EnsureInputExpression(field).convert(script);
             if (validate)
                 new VerifyInputExpression(schema, field).visit(script);
 
@@ -43,10 +42,10 @@ public class IndexingInputs extends Processor {
 
     private static class DefaultToCurrentField extends ExpressionConverter {
 
-        final String fieldName;
+        final SDField field;
 
-        DefaultToCurrentField(String fieldName) {
-            this.fieldName = fieldName;
+        DefaultToCurrentField(SDField field) {
+            this.field = field;
         }
 
         @Override
@@ -56,27 +55,28 @@ public class IndexingInputs extends Processor {
 
         @Override
         protected Expression doConvert(Expression exp) {
-            return new InputExpression(fieldName);
+            return new InputExpression(field.getName());
         }
     }
 
     private static class EnsureInputExpression extends ExpressionConverter {
 
-        final String fieldName;
+        final SDField field;
 
-        EnsureInputExpression(String fieldName) {
-            this.fieldName = fieldName;
+        EnsureInputExpression(SDField field) {
+            this.field = field;
         }
 
         @Override
         protected boolean shouldConvert(Expression exp) {
-            return exp instanceof StatementExpression;
+            return exp instanceof StatementExpression
+                   && ( field.isDocumentField() || ( field.getAttribute() != null && field.getAttribute().isMutable()));
         }
 
         @Override
         protected Expression doConvert(Expression exp) {
             if (exp.requiredInputType() != null) {
-                return new StatementExpression(new InputExpression(fieldName), exp);
+                return new StatementExpression(new InputExpression(field.getName()), exp);
             } else {
                 return exp;
             }
diff --git a/config-model/src/main/java/com/yahoo/schema/processing/IndexingValidation.java b/config-model/src/main/java/com/yahoo/schema/processing/IndexingValidation.java
index 3c7e9b4066f..d2fb16264a0 100644
--- a/config-model/src/main/java/com/yahoo/schema/processing/IndexingValidation.java
+++ b/config-model/src/main/java/com/yahoo/schema/processing/IndexingValidation.java
@@ -24,6 +24,7 @@ import com.yahoo.vespa.indexinglanguage.expressions.SummaryExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.VerificationContext;
 import com.yahoo.vespa.indexinglanguage.expressions.VerificationException;
 import com.yahoo.vespa.model.container.search.QueryProfiles;
+import com.yahoo.yolean.Exceptions;
 
 import java.util.HashSet;
 import java.util.Set;
@@ -51,7 +52,8 @@ public class IndexingValidation extends Processor {
                     converter.convert(exp); // TODO: stop doing this explicitly when visiting a script does not branch
                 }
             } catch (VerificationException e) {
-                fail(schema, field, "For expression '" + e.getExpression() + "': " + e.getMessage());
+                e.printStackTrace();
+                fail(schema, field, "For expression '" + e.getExpression() + "': " + Exceptions.toMessageString(e));
             }
         }
     }
diff --git a/config-model/src/main/java/com/yahoo/schema/processing/PredicateProcessor.java b/config-model/src/main/java/com/yahoo/schema/processing/PredicateProcessor.java
index 0362dc39c4c..1627320dc54 100644
--- a/config-model/src/main/java/com/yahoo/schema/processing/PredicateProcessor.java
+++ b/config-model/src/main/java/com/yahoo/schema/processing/PredicateProcessor.java
@@ -15,11 +15,11 @@ import com.yahoo.vespa.documentmodel.DocumentSummary;
 import com.yahoo.vespa.documentmodel.SummaryField;
 import com.yahoo.vespa.documentmodel.SummaryTransform;
 import com.yahoo.vespa.indexinglanguage.ExpressionConverter;
+import com.yahoo.vespa.indexinglanguage.expressions.ConstantExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.Expression;
 import com.yahoo.vespa.indexinglanguage.expressions.OptimizePredicateExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.OutputExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.ScriptExpression;
-import com.yahoo.vespa.indexinglanguage.expressions.SetValueExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.SetVarExpression;
 import com.yahoo.vespa.indexinglanguage.expressions.StatementExpression;
 import com.yahoo.vespa.model.container.search.QueryProfiles;
@@ -112,14 +112,14 @@ public class PredicateProcessor extends Processor {
 
     private Expression makeSetPredicateVariablesScript(BooleanIndexDefinition options) {
         List<Expression> expressions = new ArrayList<>();
-        expressions.add(new SetValueExpression(new IntegerFieldValue(options.getArity())));
+        expressions.add(new ConstantExpression(new IntegerFieldValue(options.getArity())));
         expressions.add(new SetVarExpression("arity"));
         if (options.hasLowerBound()) {
-            expressions.add(new SetValueExpression(new LongFieldValue(options.getLowerBound())));
+            expressions.add(new ConstantExpression(new LongFieldValue(options.getLowerBound())));
             expressions.add(new SetVarExpression("lower_bound"));
         }
         if (options.hasUpperBound()) {
-            expressions.add(new SetValueExpression(new LongFieldValue(options.getUpperBound())));
+            expressions.add(new ConstantExpression(new LongFieldValue(options.getUpperBound())));
             expressions.add(new SetVarExpression("upper_bound"));
         }
         return new StatementExpression(expressions);
diff --git a/config-model/src/test/java/com/yahoo/schema/AttributeSettingsTestCase.java b/config-model/src/test/java/com/yahoo/schema/AttributeSettingsTestCase.java
index 3ca182e18c2..db862dd388e 100644
--- a/config-model/src/test/java/com/yahoo/schema/AttributeSettingsTestCase.java
+++ b/config-model/src/test/java/com/yahoo/schema/AttributeSettingsTestCase.java
@@ -21,7 +21,7 @@ import static org.junit.jupiter.api.Assertions.*;
 /**
  * Attribute settings
  *
- * @author  bratseth
+ * @author bratseth
  */
 public class AttributeSettingsTestCase extends AbstractSchemaTestCase {
 
diff --git a/config-model/src/test/java/com/yahoo/schema/processing/IndexingInputsTestCase.java b/config-model/src/test/java/com/yahoo/schema/processing/IndexingInputsTestCase.java
index d420623f233..0e6744ba8f9 100644
--- a/config-model/src/test/java/com/yahoo/schema/processing/IndexingInputsTestCase.java
+++ b/config-model/src/test/java/com/yahoo/schema/processing/IndexingInputsTestCase.java
@@ -1,12 +1,15 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.schema.processing;
 
+import com.yahoo.schema.ApplicationBuilder;
 import com.yahoo.schema.parser.ParseException;
+import com.yahoo.yolean.Exceptions;
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 
 import static com.yahoo.schema.processing.AssertSearchBuilder.assertBuildFails;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 /**
  * @author Simon Thoresen Hult
@@ -24,8 +27,8 @@ public class IndexingInputsTestCase {
     @Test
     void requireThatExtraFieldInputImplicitThrows() throws IOException, ParseException {
         assertBuildFails("src/test/examples/indexing_extra_field_input_implicit.sd",
-                "For schema 'indexing_extra_field_input_implicit', field 'foo': Indexing script refers to " +
-                        "field 'foo' which is neither a field in document type 'indexing_extra_field_input_implicit' nor a mutable attribute");
+                "For schema 'indexing_extra_field_input_implicit', field 'foo': " +
+                "For expression '{ tokenize normalize stem:\"BEST\" | index foo; }': Expected string input, but no input is specified");
     }
 
     @Test
@@ -42,4 +45,59 @@ public class IndexingInputsTestCase {
                         "'foo' which is neither a field in document type 'indexing_extra_field_input_self' nor a mutable attribute");
     }
 
+    @Test
+    void testPlainInputInDerivedField() throws ParseException {
+        var schema = """
+        schema test {
+            document test {
+                field field1 type int {
+                }
+            }
+            field derived1 type int {
+                indexing: input field1 | attribute
+            }
+        }
+        """;
+        ApplicationBuilder.createFromString(schema);
+    }
+
+    @Test
+    void testWrappedInputInDerivedField() throws ParseException {
+        var schema = """
+        schema test {
+            document test {
+                field field1 type int {
+                }
+            }
+            field derived1 type int {
+                indexing: if (input field1 == 0) { 0 } else { 1 } | attribute
+            }
+        }
+        """;
+        ApplicationBuilder.createFromString(schema);
+    }
+
+    @Test
+    void testNoInputInDerivedField() throws ParseException {
+        try {
+            var schema = """
+                    schema test {
+                        document test {
+                            field field1 type int {
+                            }
+                    }
+                        field derived1 type int {
+                            indexing: attribute
+                        }
+                    }
+                    """;
+            ApplicationBuilder.createFromString(schema);
+        }
+        catch (IllegalArgumentException e) {
+            assertEquals("For schema 'test', field 'derived1': For expression '{ attribute derived1; }': " +
+                         "Expected any input, but no input is specified",
+                         Exceptions.toMessageString(e));
+        }
+    }
+
 }