fix error message for type errors mid-path

If you looked up "a.b.c" and b is not an object, it said
"a.b.c is a FOO and not an OBJECT"
now it says
"a.b is a FOO and not an OBJECT"

config/src/main/java/com/typesafe/config/impl/AbstractConfigObject.java

@@ -57,7 +57,7 @@ abstract class AbstractConfigObject extends AbstractConfigValue implements Confi
      * @param key
      * @return the unmodified raw value or null
      */
-    protected final AbstractConfigValue peekAssumingResolved(String key, String originalPath) {
+    protected final AbstractConfigValue peekAssumingResolved(String key, Path originalPath) {
         try {
             return attemptPeekWithPartialResolve(key);
         } catch (ConfigException.NotResolved e) {
@@ -138,7 +138,7 @@ abstract class AbstractConfigObject extends AbstractConfigValue implements Confi
                 }
             }
         } catch (ConfigException.NotResolved e) {
-            throw ConfigImpl.improveNotResolved(path.render(), e);
+            throw ConfigImpl.improveNotResolved(path, e);
         }
     }
 

config/src/main/java/com/typesafe/config/impl/ConfigImpl.java

@@ -526,9 +526,10 @@ public class ConfigImpl {
     // toplevel error message. the "original" exception may however have extra
     // detail about what happened. call this if you have a better "what" than
     // further down on the stack.
-    static ConfigException.NotResolved improveNotResolved(String what,
+    static ConfigException.NotResolved improveNotResolved(Path what,
             ConfigException.NotResolved original) {
-        String newMessage = what + " has not been resolved, you need to call Config#resolve(),"
+        String newMessage = what.render()
+                + " has not been resolved, you need to call Config#resolve(),"
                 + " see API docs for Config#resolve()";
         if (newMessage.equals(original.getMessage()))
             return original;

config/src/main/java/com/typesafe/config/impl/Path.java

@@ -123,6 +123,23 @@ final class Path implements Serializable {
         return p;
     }
 
+    Path subPath(int firstIndex, int lastIndex) {
+        if (lastIndex < firstIndex)
+            throw new ConfigException.BugOrBroken("bad call to subPath");
+
+        Path from = subPath(firstIndex);
+        PathBuilder pb = new PathBuilder();
+        int count = lastIndex - firstIndex;
+        while (count > 0) {
+            count -= 1;
+            pb.appendKey(from.first());
+            from = from.remainder();
+            if (from == null)
+                throw new ConfigException.BugOrBroken("subPath lastIndex out of range " + lastIndex);
+        }
+        return pb.result();
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other instanceof Path) {

config/src/main/java/com/typesafe/config/impl/SimpleConfig.java

@@ -72,7 +72,7 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
         try {
             peeked = object.peekPath(path);
         } catch (ConfigException.NotResolved e) {
-            throw ConfigImpl.improveNotResolved(pathExpression, e);
+            throw ConfigImpl.improveNotResolved(path, e);
         }
         return peeked != null && peeked.valueType() != ConfigValueType.NULL;
     }
@@ -107,33 +107,27 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
         return entries;
     }
 
-    static private AbstractConfigValue find(AbstractConfigObject self,
-            String pathExpression, ConfigValueType expected, String originalPath) {
-        Path path = Path.newPath(pathExpression);
-        return find(self, path, expected, originalPath);
-    }
-
     static private AbstractConfigValue findKey(AbstractConfigObject self, String key,
-            ConfigValueType expected, String originalPath) {
+            ConfigValueType expected, Path originalPath) {
         AbstractConfigValue v = self.peekAssumingResolved(key, originalPath);
         if (v == null)
-            throw new ConfigException.Missing(originalPath);
+            throw new ConfigException.Missing(originalPath.render());
 
         if (expected != null)
             v = DefaultTransformer.transform(v, expected);
 
         if (v.valueType() == ConfigValueType.NULL)
-            throw new ConfigException.Null(v.origin(), originalPath,
+            throw new ConfigException.Null(v.origin(), originalPath.render(),
                     expected != null ? expected.name() : null);
         else if (expected != null && v.valueType() != expected)
-            throw new ConfigException.WrongType(v.origin(), originalPath, expected.name(), v
+            throw new ConfigException.WrongType(v.origin(), originalPath.render(), expected.name(),
-                    .valueType().name());
+                    v.valueType().name());
         else
             return v;
     }
 
     static private AbstractConfigValue find(AbstractConfigObject self, Path path,
-            ConfigValueType expected, String originalPath) {
+            ConfigValueType expected, Path originalPath) {
         try {
             String key = path.first();
             Path next = path.remainder();
@@ -141,33 +135,38 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
                 return findKey(self, key, expected, originalPath);
             } else {
                 AbstractConfigObject o = (AbstractConfigObject) findKey(self, key,
-                        ConfigValueType.OBJECT, originalPath);
+                        ConfigValueType.OBJECT,
+                        originalPath.subPath(0, originalPath.length() - next.length()));
                 assert (o != null); // missing was supposed to throw
                 return find(o, next, expected, originalPath);
             }
         } catch (ConfigException.NotResolved e) {
-            throw ConfigImpl.improveNotResolved(path.render(), e);
+            throw ConfigImpl.improveNotResolved(path, e);
         }
     }
 
-    AbstractConfigValue find(String pathExpression, ConfigValueType expected,
+    AbstractConfigValue find(Path pathExpression, ConfigValueType expected, Path originalPath) {
-            String originalPath) {
         return find(object, pathExpression, expected, originalPath);
     }
 
+    AbstractConfigValue find(String pathExpression, ConfigValueType expected) {
+        Path path = Path.newPath(pathExpression);
+        return find(path, expected, path);
+    }
+
     @Override
     public AbstractConfigValue getValue(String path) {
-        return find(path, null, path);
+        return find(path, null);
     }
 
     @Override
     public boolean getBoolean(String path) {
-        ConfigValue v = find(path, ConfigValueType.BOOLEAN, path);
+        ConfigValue v = find(path, ConfigValueType.BOOLEAN);
         return (Boolean) v.unwrapped();
     }
 
     private ConfigNumber getConfigNumber(String path) {
-        ConfigValue v = find(path, ConfigValueType.NUMBER, path);
+        ConfigValue v = find(path, ConfigValueType.NUMBER);
         return (ConfigNumber) v;
     }
 
@@ -194,20 +193,19 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
 
     @Override
     public String getString(String path) {
-        ConfigValue v = find(path, ConfigValueType.STRING, path);
+        ConfigValue v = find(path, ConfigValueType.STRING);
         return (String) v.unwrapped();
     }
 
     @Override
     public ConfigList getList(String path) {
-        AbstractConfigValue v = find(path, ConfigValueType.LIST, path);
+        AbstractConfigValue v = find(path, ConfigValueType.LIST);
         return (ConfigList) v;
     }
 
     @Override
     public AbstractConfigObject getObject(String path) {
-        AbstractConfigObject obj = (AbstractConfigObject) find(path,
+        AbstractConfigObject obj = (AbstractConfigObject) find(path, ConfigValueType.OBJECT);
-                ConfigValueType.OBJECT, path);
         return obj;
     }
 
@@ -218,7 +216,7 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
 
     @Override
     public Object getAnyRef(String path) {
-        ConfigValue v = find(path, null, path);
+        ConfigValue v = find(path, null);
         return v.unwrapped();
     }
 
@@ -228,7 +226,7 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
         try {
             size = getLong(path);
         } catch (ConfigException.WrongType e) {
-            ConfigValue v = find(path, ConfigValueType.STRING, path);
+            ConfigValue v = find(path, ConfigValueType.STRING);
             size = parseBytes((String) v.unwrapped(),
                     v.origin(), path);
         }
@@ -248,7 +246,7 @@ final class SimpleConfig implements Config, MergeableValue, Serializable {
         try {
             ns = TimeUnit.MILLISECONDS.toNanos(getLong(path));
         } catch (ConfigException.WrongType e) {
-            ConfigValue v = find(path, ConfigValueType.STRING, path);
+            ConfigValue v = find(path, ConfigValueType.STRING);
             ns = parseDuration((String) v.unwrapped(), v.origin(), path);
         }
         return ns;