SOLR-14687: childPath starting with / is BAD_REQUEST; empty childPath == no childPath

Copilot · dsmiley · Copilot · commit 58e660b5974c · 2026-03-11T13:18:05.000Z
Co-authored-by: dsmiley &lt;377295+dsmiley@users.noreply.github.com&gt;
diff --git a/solr/core/src/java/org/apache/solr/search/join/BlockJoinParentQParser.java b/solr/core/src/java/org/apache/solr/search/join/BlockJoinParentQParser.java
@@ -150,13 +150,12 @@ protected Query parseUsingParentPath(String parentPath) throws SyntaxError {
 
     String childPath = localParams.get(CHILD_PATH_PARAM);
     if (childPath != null) {
-      // strip leading slash if present
       if (childPath.startsWith("/")) {
-        childPath = childPath.substring(1);
+        throw new SolrException(
+            SolrException.ErrorCode.BAD_REQUEST, CHILD_PATH_PARAM + " must not start with '/'");
       }
       if (childPath.isEmpty()) {
-        throw new SolrException(
-            SolrException.ErrorCode.BAD_REQUEST, CHILD_PATH_PARAM + " must not be empty");
+        childPath = null; // treat empty as not specified
       }
     }
 

Original file line number	Diff line number	Diff line change
`@@ -150,13 +150,12 @@ protected Query parseUsingParentPath(String parentPath) throws SyntaxError {`
`150`	`150`
`151`	`151`	`String childPath = localParams.get(CHILD_PATH_PARAM);`
`152`	`152`	`if (childPath != null) {`
`153`		`- // strip leading slash if present`
`154`	`153`	`if (childPath.startsWith("/")) {`
`155`		`- childPath = childPath.substring(1);`
	`154`	`+ throw new SolrException(`
	`155`	`+ SolrException.ErrorCode.BAD_REQUEST, CHILD_PATH_PARAM + " must not start with '/'");`
`156`	`156`	`}`
`157`	`157`	`if (childPath.isEmpty()) {`
`158`		`- throw new SolrException(`
`159`		`- SolrException.ErrorCode.BAD_REQUEST, CHILD_PATH_PARAM + " must not be empty");`
	`158`	`+ childPath = null; // treat empty as not specified`
`160`	`159`	`}`
`161`	`160`	`}`
`162`	`161`