Relativize substitutions when including a file

This is needed because we resolve substitutions only
as the last step, and against the whole tree not
against each file.

Special handling is needed so that fallback to
system properties and environment variables still
works properly.

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

@@ -270,40 +270,63 @@ abstract class AbstractConfigObject extends AbstractConfigValue implements
         }
     }
 
-    @Override
-    AbstractConfigObject resolveSubstitutions(SubstitutionResolver resolver,
-            int depth,
-            boolean withFallbacks) {
-        if (resolveStatus() == ResolveStatus.RESOLVED)
-            return this;
-
+    private AbstractConfigObject modify(Modifier modifier,
+            ResolveStatus newResolveStatus) {
         Map<String, AbstractConfigValue> changes = null;
         for (String k : keySet()) {
             AbstractConfigValue v = peek(k);
-            AbstractConfigValue resolved = resolver.resolve(v, depth,
-                    withFallbacks);
-            if (resolved != v) {
+            AbstractConfigValue modified = modifier.modifyChild(v);
+            if (modified != v) {
                 if (changes == null)
                     changes = new HashMap<String, AbstractConfigValue>();
-                changes.put(k, resolved);
+                changes.put(k, modified);
             }
         }
         if (changes == null) {
-            return newCopy(transformer, ResolveStatus.RESOLVED);
+            return newCopy(transformer, newResolveStatus);
         } else {
-            Map<String, AbstractConfigValue> resolved = new HashMap<String, AbstractConfigValue>();
+            Map<String, AbstractConfigValue> modified = new HashMap<String, AbstractConfigValue>();
             for (String k : keySet()) {
                 if (changes.containsKey(k)) {
-                    resolved.put(k, changes.get(k));
+                    modified.put(k, changes.get(k));
                 } else {
-                    resolved.put(k, peek(k));
+                    modified.put(k, peek(k));
                 }
             }
-            return new SimpleConfigObject(origin(), transformer, resolved,
-                    ResolveStatus.RESOLVED);
+            return new SimpleConfigObject(origin(), transformer, modified,
+                    newResolveStatus);
         }
     }
 
+    @Override
+    AbstractConfigObject resolveSubstitutions(final SubstitutionResolver resolver,
+            final int depth,
+            final boolean withFallbacks) {
+        if (resolveStatus() == ResolveStatus.RESOLVED)
+            return this;
+
+        return modify(new Modifier() {
+
+            @Override
+            public AbstractConfigValue modifyChild(AbstractConfigValue v) {
+                return resolver.resolve(v, depth, withFallbacks);
+            }
+
+        }, ResolveStatus.RESOLVED);
+    }
+
+    @Override
+    AbstractConfigObject relativized(final Path prefix) {
+        return modify(new Modifier() {
+
+            @Override
+            public AbstractConfigValue modifyChild(AbstractConfigValue v) {
+                return v.relativized(prefix);
+            }
+
+        }, resolveStatus());
+    }
+
     @Override
     public AbstractConfigValue get(Object key) {
         if (key instanceof String)

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

@@ -38,6 +38,26 @@ abstract class AbstractConfigValue implements ConfigValue {
         return ResolveStatus.RESOLVED;
     }
 
+    /**
+     * This is used when including one file in another; the included file is
+     * relativized to the path it's included into in the parent file. The point
+     * is that if you include a file at foo.bar in the parent, and the included
+     * file as a substitution ${a.b.c}, the included substitution now needs to
+     * be ${foo.bar.a.b.c} because we resolve substitutions globally only after
+     * parsing everything.
+     *
+     * @param prefix
+     * @return value relativized to the given path or the same value if nothing
+     *         to do
+     */
+    AbstractConfigValue relativized(Path prefix) {
+        return this;
+    }
+
+    protected interface Modifier {
+        AbstractConfigValue modifyChild(AbstractConfigValue v);
+    }
+
     @Override
     public AbstractConfigValue withFallback(ConfigValue other) {
         return this;

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

@@ -90,6 +90,15 @@ final class ConfigDelayedMerge extends AbstractConfigValue implements
         return ResolveStatus.UNRESOLVED;
     }
 
+    @Override
+    ConfigDelayedMerge relativized(Path prefix) {
+        List<AbstractConfigValue> newStack = new ArrayList<AbstractConfigValue>();
+        for (AbstractConfigValue o : stack) {
+            newStack.add(o.relativized(prefix));
+        }
+        return new ConfigDelayedMerge(origin(), newStack);
+    }
+
     @Override
     public AbstractConfigValue withFallback(ConfigValue other) {
         if (other instanceof AbstractConfigObject

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

@@ -91,6 +91,15 @@ class ConfigDelayedMergeObject extends AbstractConfigObject implements
         return ResolveStatus.UNRESOLVED;
     }
 
+    @Override
+    ConfigDelayedMergeObject relativized(Path prefix) {
+        List<AbstractConfigValue> newStack = new ArrayList<AbstractConfigValue>();
+        for (AbstractConfigValue o : stack) {
+            newStack.add(o.relativized(prefix));
+        }
+        return new ConfigDelayedMergeObject(origin(), transformer, newStack);
+    }
+
     @Override
     public ConfigDelayedMergeObject withFallback(ConfigValue other) {
         if (other instanceof AbstractConfigObject

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

@@ -22,10 +22,18 @@ final class ConfigSubstitution extends AbstractConfigValue implements
     // have to be resolved to values, then if there's more
     // than one piece everything is stringified and concatenated
     final private List<Object> pieces;
+    // the length of any prefixes added with relativized()
+    final int prefixLength;
 
     ConfigSubstitution(ConfigOrigin origin, List<Object> pieces) {
+        this(origin, pieces, 0);
+    }
+
+    private ConfigSubstitution(ConfigOrigin origin, List<Object> pieces,
+            int prefixLength) {
         super(origin);
         this.pieces = pieces;
+        this.prefixLength = prefixLength;
     }
 
     @Override
@@ -104,15 +112,17 @@ final class ConfigSubstitution extends AbstractConfigValue implements
         ConfigValue result = findInObject(resolver.root(), resolver, subst,
                 depth, withFallbacks);
         if (withFallbacks) {
+            // when looking up system props and env variables,
+            // we don't want the prefix that was added when
+            // we were included in another file.
+            Path unprefixed = subst.subPath(prefixLength);
             if (result == null) {
                 result = findInObject(ConfigImpl.systemPropertiesConfig(),
-                        null,
-                        subst, depth, withFallbacks);
+                        null, unprefixed, depth, withFallbacks);
             }
             if (result == null) {
                 result = findInObject(ConfigImpl.envVariablesConfig(), null,
-                        subst,
-                        depth, withFallbacks);
+                        unprefixed, depth, withFallbacks);
             }
         }
         if (result == null) {
@@ -173,6 +183,25 @@ final class ConfigSubstitution extends AbstractConfigValue implements
         return ResolveStatus.UNRESOLVED;
     }
 
+    // when you graft a substitution into another object,
+    // you have to prefix it with the location in that object
+    // where you grafted it; but save prefixLength so
+    // system property and env variable lookups don't get
+    // broken.
+    @Override
+    ConfigSubstitution relativized(Path prefix) {
+        List<Object> newPieces = new ArrayList<Object>();
+        for (Object p : pieces) {
+            if (p instanceof Path) {
+                newPieces.add(((Path) p).prepend(prefix));
+            } else {
+                newPieces.add(p);
+            }
+        }
+        return new ConfigSubstitution(origin(), newPieces, prefixLength
+                + prefix.length());
+    }
+
     @Override
     protected boolean canEqual(Object other) {
         return other instanceof ConfigSubstitution;

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

@@ -14,6 +14,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
@@ -118,6 +119,7 @@ final class Parser {
         final private IncludeHandler includer;
         final private SyntaxFlavor flavor;
         final private ConfigOrigin baseOrigin;
+        final private LinkedList<Path> pathStack;
 
         ParseContext(SyntaxFlavor flavor, ConfigOrigin origin,
                 Iterator<Token> tokens, IncludeHandler includer) {
@@ -127,6 +129,7 @@ final class Parser {
             this.flavor = flavor;
             this.baseOrigin = origin;
             this.includer = includer;
+            this.pathStack = new LinkedList<Path>();
         }
 
         private Token nextToken() {
@@ -397,6 +400,11 @@ final class Parser {
                 String name = (String) Tokens.getValue(t).unwrapped();
                 AbstractConfigObject obj = includer.include(name);
 
+                if (!pathStack.isEmpty()) {
+                    Path prefix = new Path(pathStack);
+                    obj = obj.relativized(prefix);
+                }
+
                 for (String key : obj.keySet()) {
                     AbstractConfigValue v = obj.get(key);
                     AbstractConfigValue existing = values.get(key);
@@ -446,6 +454,9 @@ final class Parser {
                     Path path = parseKey(t);
                     Token afterKey = nextTokenIgnoringNewline();
 
+                    // path must be on-stack while we parse the value
+                    pathStack.push(path);
+
                     Token valueToken;
                     AbstractConfigValue newValue;
                     if (flavor == SyntaxFlavor.CONF
@@ -464,6 +475,8 @@ final class Parser {
                         newValue = parseValue(valueToken);
                     }
 
+                    pathStack.pop();
+
                     String key = path.first();
                     Path remaining = path.remainder();
 

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

@@ -1,5 +1,8 @@
 package com.typesafe.config.impl;
 
+import java.util.Iterator;
+import java.util.List;
+
 import com.typesafe.config.ConfigException;
 
 final class Path {
@@ -27,6 +30,25 @@ final class Path {
         }
     }
 
+    // append all the paths in the list together into one path
+    Path(List<Path> pathsToConcat) {
+        if (pathsToConcat.isEmpty())
+            throw new ConfigException.BugOrBroken("empty path");
+
+        Iterator<Path> i = pathsToConcat.iterator();
+        Path firstPath = i.next();
+        this.first = firstPath.first;
+
+        PathBuilder pb = new PathBuilder();
+        if (firstPath.remainder != null) {
+            pb.appendPath(firstPath.remainder);
+        }
+        while (i.hasNext()) {
+            pb.appendPath(i.next());
+        }
+        this.remainder = pb.result();
+    }
+
     String first() {
         return first;
     }
@@ -35,6 +57,33 @@ final class Path {
         return remainder;
     }
 
+    Path prepend(Path toPrepend) {
+        PathBuilder pb = new PathBuilder();
+        pb.appendPath(toPrepend);
+        pb.appendPath(this);
+        return pb.result();
+    }
+
+    int length() {
+        int count = 1;
+        Path p = remainder;
+        while (p != null) {
+            count += 1;
+            p = p.remainder;
+        }
+        return count;
+    }
+
+    Path subPath(int removeFromFront) {
+        int count = removeFromFront;
+        Path p = this;
+        while (p != null && count > 0) {
+            count -= 1;
+            p = p.remainder;
+        }
+        return p;
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other instanceof Path) {

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

@@ -25,7 +25,25 @@ final class PathBuilder {
         keys.push(key);
     }
 
+    void appendPath(Path path) {
+        checkCanAppend();
+
+        String first = path.first();
+        Path remainder = path.remainder();
+        while (true) {
+            keys.push(first);
+            if (remainder != null) {
+                first = remainder.first();
+                remainder = remainder.remainder();
+            } else {
+                break;
+            }
+        }
+    }
+
     Path result() {
+        // note: if keys is empty, we want to return null, which is a valid
+        // empty path
         if (result == null) {
             Path remainder = null;
             while (!keys.isEmpty()) {

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

@@ -47,21 +47,16 @@ final class SimpleConfigList extends AbstractConfigValue implements ConfigList {
         return ResolveStatus.fromBoolean(resolved);
     }
 
-    @Override
-    SimpleConfigList resolveSubstitutions(SubstitutionResolver resolver, int depth,
-            boolean withFallbacks) {
-        if (resolved)
-            return this;
-
+    private SimpleConfigList modify(Modifier modifier,
+            ResolveStatus newResolveStatus) {
         // lazy-create for optimization
         List<AbstractConfigValue> changed = null;
         int i = 0;
         for (AbstractConfigValue v : value) {
-            AbstractConfigValue resolved = resolver.resolve(v, depth,
-                    withFallbacks);
+            AbstractConfigValue modified = modifier.modifyChild(v);
 
             // lazy-create the new list if required
-            if (changed == null && resolved != v) {
+            if (changed == null && modified != v) {
                 changed = new ArrayList<AbstractConfigValue>();
                 for (int j = 0; j < i; ++j) {
                     changed.add(value.get(j));
@@ -71,7 +66,7 @@ final class SimpleConfigList extends AbstractConfigValue implements ConfigList {
             // once the new list is created, all elements
             // have to go in it.
             if (changed != null) {
-                changed.add(resolved);
+                changed.add(modified);
             }
 
             i += 1;
@@ -81,13 +76,38 @@ final class SimpleConfigList extends AbstractConfigValue implements ConfigList {
             if (changed.size() != value.size())
                 throw new ConfigException.BugOrBroken(
                         "substituted list's size doesn't match");
-            return new SimpleConfigList(origin(), changed,
-                    ResolveStatus.RESOLVED);
+            return new SimpleConfigList(origin(), changed, newResolveStatus);
         } else {
             return this;
         }
     }
 
+    @Override
+    SimpleConfigList resolveSubstitutions(final SubstitutionResolver resolver,
+            final int depth, final boolean withFallbacks) {
+        if (resolved)
+            return this;
+
+        return modify(new Modifier() {
+            @Override
+            public AbstractConfigValue modifyChild(AbstractConfigValue v) {
+                return resolver.resolve(v, depth, withFallbacks);
+            }
+
+        }, ResolveStatus.RESOLVED);
+    }
+
+    @Override
+    SimpleConfigList relativized(final Path prefix) {
+        return modify(new Modifier() {
+            @Override
+            public AbstractConfigValue modifyChild(AbstractConfigValue v) {
+                return v.relativized(prefix);
+            }
+
+        }, resolveStatus());
+    }
+
     @Override
     protected boolean canEqual(Object other) {
         return other instanceof SimpleConfigList;

src/test/resources/test01.conf

@@ -62,5 +62,17 @@
         "megsList" : [1M, 1024K, 1048576],
         "megAsNumber" : 1048576,
         "halfMeg" : 0.5M
+    },
+
+    "system" : {
+        "javaversion" : ${java.version},
+        "userhome" : ${user.home},
+        "home" : ${HOME},
+        "pwd" : ${PWD},
+        "shell" : ${SHELL},
+        "lang" : ${LANG},
+        "path" : ${PATH},
+        "not_here" : ${NOT_HERE},
+        "concatenated" : Your Java version is ${system.javaversion} and your user.home is ${system.userhome}
     }
 }

src/test/scala/com/typesafe/config/impl/ConfigSubstitutionTest.scala

@@ -284,4 +284,29 @@ class ConfigSubstitutionTest extends TestUtils {
             throw new Exception("None of the env vars we tried to use for testing were set")
         }
     }
+
+    @Test
+    def fallbackToEnvWhenRelativized() {
+        import scala.collection.JavaConverters._
+
+        val values = new java.util.HashMap[String, AbstractConfigValue]()
+
+        values.put("a", substEnvVarObject.relativized(new Path("a")))
+
+        val resolved = resolve(new SimpleConfigObject(fakeOrigin(), values));
+
+        var existed = 0
+        for (k <- resolved.getObject("a").keySet().asScala) {
+            val e = System.getenv(k.toUpperCase());
+            if (e != null) {
+                existed += 1
+                assertEquals(e, resolved.getObject("a").getString(k))
+            } else {
+                assertEquals(nullValue, resolved.getObject("a").get(k))
+            }
+        }
+        if (existed == 0) {
+            throw new Exception("None of the env vars we tried to use for testing were set")
+        }
+    }
 }

src/test/scala/com/typesafe/config/impl/ConfigTest.scala

@@ -606,6 +606,20 @@ class ConfigTest extends TestUtils {
         conf.toString()
     }
 
+    @Test
+    def test01SystemFallbacks() {
+        val conf = Config.load("test01")
+        val jv = System.getProperty("java.version")
+        assertNotNull(jv)
+        assertEquals(jv, conf.getString("system.javaversion"))
+        val home = System.getenv("HOME")
+        if (home != null) {
+            assertEquals(home, conf.getString("system.home"))
+        } else {
+            assertEquals(nullValue, conf.get("system.home"))
+        }
+    }
+
     @Test
     def test01LoadWithConfigConfig() {
         val conf = Config.load(new ConfigConfig("test01"))
@@ -651,6 +665,26 @@ class ConfigTest extends TestUtils {
         assertEquals(57, conf.getInt("test02.a.b.c"))
         // equiv01/original.json was included (it has a slash in the name)
         assertEquals("a", conf.getString("equiv01.strings.a"))
+
+        // Now check that substitutions still work
+        assertEquals(42, conf.getInt("test01.ints.fortyTwoAgain"))
+        assertEquals(Seq("a", "b", "c"), conf.getStringList("test01.arrays.ofString").asScala)
+        assertEquals(103, conf.getInt("test02.103_a"))
+
+        // and system fallbacks still work
+        val jv = System.getProperty("java.version")
+        assertNotNull(jv)
+        assertEquals(jv, conf.getString("test01.system.javaversion"))
+        val home = System.getenv("HOME")
+        if (home != null) {
+            assertEquals(home, conf.getString("test01.system.home"))
+        } else {
+            assertEquals(nullValue, conf.get("test01.system.home"))
+        }
+        val concatenated = conf.getString("test01.system.concatenated")
+        assertTrue(concatenated.contains("Your Java version"))
+        assertTrue(concatenated.contains(jv))
+        assertTrue(concatenated.contains(conf.getString("test01.system.userhome")))
     }
 
     @Test

src/test/scala/com/typesafe/config/impl/PathTest.scala

@@ -2,6 +2,7 @@ package com.typesafe.config.impl
 
 import org.junit.Assert._
 import org.junit._
+import scala.collection.JavaConverters._
 
 class PathTest extends TestUtils {
 
@@ -42,4 +43,23 @@ class PathTest extends TestUtils {
         assertEquals("\"foo.bar\"", path("foo.bar").render())
         assertEquals("foo bar", path("foo bar").render())
     }
+
+    @Test
+    def pathFromPathList() {
+        assertEquals(path("foo"), new Path(List(path("foo")).asJava))
+        assertEquals(path("foo", "bar", "baz", "boo"), new Path(List(path("foo", "bar"),
+            path("baz", "boo")).asJava))
+    }
+
+    @Test
+    def pathPrepend() {
+        assertEquals(path("foo", "bar"), path("bar").prepend(path("foo")))
+        assertEquals(path("a", "b", "c", "d"), path("c", "d").prepend(path("a", "b")))
+    }
+
+    @Test
+    def pathLength() {
+        assertEquals(1, path("foo").length())
+        assertEquals(2, path("foo", "bar").length())
+    }
 }