diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java index 1e8ed503c39..dbbc8ff20e8 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java @@ -943,10 +943,15 @@ public class Configuration implements Iterable>, * * If var is unbounded the current state of expansion "prefix${var}suffix" is * returned. - * - * If a cycle is detected: replacing var1 requires replacing var2 ... requires - * replacing var1, i.e., the cycle is shorter than - * {@link Configuration#MAX_SUBST} then the original expr is returned. + *

+ * This function also detects self-referential substitutions, i.e. + *

+   *   {@code
+   *   foo.bar = ${foo.bar}
+   *   }
+   * 
+ * If a cycle is detected then the original expr is returned. Loops + * involving multiple substitutions are not detected. * * @param expr the literal value of a config key * @return null if expr is null, otherwise the value resulting from expanding @@ -959,7 +964,6 @@ public class Configuration implements Iterable>, return null; } String eval = expr; - Set evalSet = null; for(int s = 0; s < MAX_SUBST; s++) { final int[] varBounds = findSubVariable(eval); if (varBounds[SUB_START_IDX] == -1) { @@ -1004,15 +1008,12 @@ public class Configuration implements Iterable>, return eval; // return literal ${var}: var is unbound } - // prevent recursive resolution - // final int dollar = varBounds[SUB_START_IDX] - "${".length(); final int afterRightBrace = varBounds[SUB_END_IDX] + "}".length(); final String refVar = eval.substring(dollar, afterRightBrace); - if (evalSet == null) { - evalSet = new HashSet(); - } - if (!evalSet.add(refVar)) { + + // detect self-referential values + if (val.contains(refVar)) { return expr; // return original expression if there is a loop } diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java index 917ccbce29c..17112f5c9f6 100644 --- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java +++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java @@ -168,6 +168,9 @@ public class TestConfiguration extends TestCase { declareProperty("my.fullfile", "${my.base}/${my.file}${my.suffix}", "/tmp/hadoop_user/hello.txt"); // check that undefined variables are returned as-is declareProperty("my.failsexpand", "a${my.undefvar}b", "a${my.undefvar}b"); + // check that multiple variable references are resolved + declareProperty("my.user.group", "${user.name} ${user.name}", + "hadoop_user hadoop_user"); endConfig(); Path fileResource = new Path(CONFIG); mock.addResource(fileResource); @@ -1508,7 +1511,7 @@ public class TestConfiguration extends TestCase { } } - public void testInvalidSubstitutation() { + public void testInvalidSubstitution() { final Configuration configuration = new Configuration(false); // 2-var loops @@ -1522,25 +1525,6 @@ public class TestConfiguration extends TestCase { configuration.set(key, keyExpression); assertEquals("Unexpected value", keyExpression, configuration.get(key)); } - - // - // 3-variable loops - // - - final String expVal1 = "${test.var2}"; - String testVar1 = "test.var1"; - configuration.set(testVar1, expVal1); - configuration.set("test.var2", "${test.var3}"); - configuration.set("test.var3", "${test.var1}"); - assertEquals("Unexpected value", expVal1, configuration.get(testVar1)); - - // 3-variable loop with non-empty value prefix/suffix - // - final String expVal2 = "foo2${test.var2}bar2"; - configuration.set(testVar1, expVal2); - configuration.set("test.var2", "foo3${test.var3}bar3"); - configuration.set("test.var3", "foo1${test.var1}bar1"); - assertEquals("Unexpected value", expVal2, configuration.get(testVar1)); } public void testIncompleteSubbing() {