Support optional 'path' config type

Initial work needed for this to work (config definition and config library)

7 files changed, 34 insertions, 4 deletions

diff --git a/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java b/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
index e86b13b2c98..0dbc40a246c 100644
--- a/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
+++ b/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
@@ -21,6 +21,7 @@ import java.util.Deque;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.logging.Logger;
 
@@ -213,7 +214,10 @@ public class ConfigPayloadApplier<T extends ConfigInstance.Builder> {
         Inspector value = (Inspector)rawValue;
         if (isPathField(builder, methodName))
             return resolvePath(value.asString());
-        else if (isUrlField(builder, methodName))
+        if (isOptionalPathField(builder, methodName)) {
+            String v = value.asString();
+            return resolvePath(v.isEmpty() ? Optional.empty() : Optional.of(v));
+        } else if (isUrlField(builder, methodName))
             return value.asString().isEmpty() ? "" : resolveUrl(value.asString());
         else if (isModelField(builder, methodName))
             return value.asString().isEmpty() ? "" : resolveModel(value.asString());
@@ -234,6 +238,10 @@ public class ConfigPayloadApplier<T extends ConfigInstance.Builder> {
         return new FileReference(path.toString());
     }
 
+    private Optional<FileReference> resolvePath(Optional<String> value) {
+        return value.isEmpty() ? Optional.empty() : Optional.of(resolvePath(value.get()));
+    }
+
     private UrlReference resolveUrl(String url) {
         if ( ! isClientside()) return new UrlReference(url);
         File file = urlDownloader.waitFor(new UrlReference(url), 60 * 60);
@@ -319,6 +327,16 @@ public class ConfigPayloadApplier<T extends ConfigInstance.Builder> {
         return isFieldType(pathFieldSet, builder, methodName, FileReference.class);
     }
 
+    /**
+     * Checks if this field is of type 'path', in which
+     * case some special handling might be needed. Caches the result.
+     */
+    private final Set<String> optionalPathFieldSet = new HashSet<>();
+    private boolean isOptionalPathField(Object builder, String methodName) {
+        // Paths are stored as Optional<FileReference> in Builder.
+        return isFieldType(optionalPathFieldSet, builder, methodName, Optional.class);
+    }
+
     private final Set<String> urlFieldSet = new HashSet<>();
     private boolean isUrlField(Object builder, String methodName) {
         // Urls are stored as UrlReference in Builder.
diff --git a/config/src/test/java/com/yahoo/config/subscription/CfgConfigPayloadBuilderTest.java b/config/src/test/java/com/yahoo/config/subscription/CfgConfigPayloadBuilderTest.java
index a6273ad5ccb..0e50be83e7a 100644
--- a/config/src/test/java/com/yahoo/config/subscription/CfgConfigPayloadBuilderTest.java
+++ b/config/src/test/java/com/yahoo/config/subscription/CfgConfigPayloadBuilderTest.java
@@ -34,6 +34,7 @@ public class CfgConfigPayloadBuilderTest {
                 "        'parent:'",
                 "    ],",
                 "    'pathVal': 'src/test/resources/configs/def-files/function-test.def',",
+                "    'optionalPathVal': 'src/test/resources/configs/def-files/function-test.def',",
                 "    'string_val': 'foo',",
                 "    'myStructMap': {",
                 "        'one': {",
diff --git a/config/src/test/java/com/yahoo/config/subscription/ConfigInstancePayloadTest.java b/config/src/test/java/com/yahoo/config/subscription/ConfigInstancePayloadTest.java
index c656bfe1a60..f09462eb634 100644
--- a/config/src/test/java/com/yahoo/config/subscription/ConfigInstancePayloadTest.java
+++ b/config/src/test/java/com/yahoo/config/subscription/ConfigInstancePayloadTest.java
@@ -13,6 +13,7 @@ import org.junit.Test;
 import java.io.File;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 
 import static com.yahoo.foo.FunctionTestConfig.*;
 import static org.junit.Assert.assertNotNull;
@@ -46,6 +47,7 @@ public class ConfigInstancePayloadTest {
                 refwithdef(":parent:").
                 fileVal("etc").
                 pathVal(FileReference.mockFileReferenceForUnitTesting(new File("src/test/resources/configs/def-files/function-test.def"))).
+                optionalPathVal(Optional.of(FileReference.mockFileReferenceForUnitTesting(new File("src/test/resources/configs/def-files/function-test.def")))).
                 boolarr(false).
                 longarr(9223372036854775807L).
                 longarr(-9223372036854775808L).
diff --git a/config/src/test/java/com/yahoo/config/subscription/FunctionTest.java b/config/src/test/java/com/yahoo/config/subscription/FunctionTest.java
index 8656c0e945f..7a3b0e437f2 100644
--- a/config/src/test/java/com/yahoo/config/subscription/FunctionTest.java
+++ b/config/src/test/java/com/yahoo/config/subscription/FunctionTest.java
@@ -30,7 +30,7 @@ public class FunctionTest {
     public static final String PATH = "src/test/resources/configs/function-test/";
 
     private FunctionTestConfig config;
-    private ConfigSourceSet sourceSet = new ConfigSourceSet("function-test");
+    private final ConfigSourceSet sourceSet = new ConfigSourceSet("function-test");
 
     public void configure(FunctionTestConfig config, ConfigSourceSet sourceSet) {
         this.config = config;
@@ -222,6 +222,8 @@ public class FunctionTest {
         assertEquals(":parent", config.refarr(1));
         assertEquals("parent:", config.refarr(2));
         assertEquals("bin", config.fileArr(0).value());
+        assertEquals("function-test.def", config.pathVal().toFile().getName());
+        assertEquals("function-test.def", config.optionalPathVal().get().toFile().getName());  // TODO
         assertEquals("pom.xml", config.pathArr(0).toString());
         assertEquals("pom.xml", config.pathMap("one").toString());
 
diff --git a/config/src/test/java/com/yahoo/vespa/config/ConfigDefinitionBuilderTest.java b/config/src/test/java/com/yahoo/vespa/config/ConfigDefinitionBuilderTest.java
index a9f09951d7e..fa1ec815047 100644
--- a/config/src/test/java/com/yahoo/vespa/config/ConfigDefinitionBuilderTest.java
+++ b/config/src/test/java/com/yahoo/vespa/config/ConfigDefinitionBuilderTest.java
@@ -77,10 +77,14 @@ public class ConfigDefinitionBuilderTest {
         assertThat(def.getFileDefs().size(), is(1));
         assertNotNull(def.getFileDefs().get("fileVal"));
 
-        assertThat(def.getArrayDefs().size(), is(9));
+        // An array does not have to have any elements set
+        assertThat(def.getArrayDefs().size(), is(10));
         assertNotNull(def.getArrayDefs().get("boolarr"));
         assertThat(def.getArrayDefs().get("boolarr").getTypeSpec().getType(), is("bool"));
 
+        assertNotNull(def.getArrayDefs().get("boolarrEmpty"));
+        assertThat(def.getArrayDefs().get("boolarrEmpty").getTypeSpec().getType(), is("bool"));
+
         assertNotNull(def.getArrayDefs().get("enumarr"));
         assertThat(def.getArrayDefs().get("enumarr").getTypeSpec().getType(), is("enum"));
         assertThat(def.getArrayDefs().get("enumarr").getTypeSpec().getEnumVals().toString(), is("[ARRAY, VALUES]"));
diff --git a/config/src/test/resources/configs/def-files/function-test.def b/config/src/test/resources/configs/def-files/function-test.def
index 4c4cb6bf08b..b97713b18f3 100644
--- a/config/src/test/resources/configs/def-files/function-test.def
+++ b/config/src/test/resources/configs/def-files/function-test.def
@@ -42,8 +42,10 @@ refval reference
 refwithdef reference default=":parent:"
 fileVal file
 pathVal path
+optionalPathVal path optional
 
 boolarr[] bool
+boolarrEmpty[] bool
 intarr[] int
 longarr[] long
 doublearr[] double
diff --git a/config/src/test/resources/configs/function-test/variableaccess.txt b/config/src/test/resources/configs/function-test/variableaccess.txt
index 997de21750d..8c2cadcdbbc 100644
--- a/config/src/test/resources/configs/function-test/variableaccess.txt
+++ b/config/src/test/resources/configs/function-test/variableaccess.txt
@@ -14,7 +14,8 @@ enumwithdef BAR2
 refval :parent:
 refwithdef ":parent:"
 fileVal "etc"
-pathVal "pom.xml"
+pathVal "function-test.def"
+optionalPathVal "function-test.def"
 boolarr[1]
 boolarr[0] false
 intarr[0]