From 9ecf9ef5a673ff834c7806dd284ce3c4bb3d0e6a Mon Sep 17 00:00:00 2001
From: David Smiley <dsmiley@apache.org>
Date: Sun, 31 May 2026 21:44:31 -0400
Subject: [PATCH 1/3] HttpJettySolrClient: use better exception

Fix ensures that LBSolrClient treats it as a retryable connection failure.
---
 .../apache/solr/client/solrj/jetty/HttpJettySolrClient.java   | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/solr/solrj-jetty/src/java/org/apache/solr/client/solrj/jetty/HttpJettySolrClient.java b/solr/solrj-jetty/src/java/org/apache/solr/client/solrj/jetty/HttpJettySolrClient.java
index fdd5fa8443b9..46f0a23aec67 100644
--- a/solr/solrj-jetty/src/java/org/apache/solr/client/solrj/jetty/HttpJettySolrClient.java
+++ b/solr/solrj-jetty/src/java/org/apache/solr/client/solrj/jetty/HttpJettySolrClient.java
@@ -507,6 +507,10 @@ public NamedList<Object> request(SolrRequest<?> solrRequest, String collection)
             "IOException occurred when talking to server at: " + url, cause);
       }
       throw new SolrServerException(cause.getMessage(), cause);
+    } catch (IllegalStateException e) {
+      // Jetty HTTP/2 throws IllegalStateException ("session closed") when the connection is lost.
+      abortCause = e;
+      throw new SolrServerException("Connection lost at: " + url, new IOException(e));
     } catch (SolrServerException | RuntimeException sse) {
       abortCause = sse;
       throw sse;

From 3cc013258ace1b683ce968333285093f5e852113 Mon Sep 17 00:00:00 2001
From: David Smiley <dsmiley@apache.org>
Date: Mon, 1 Jun 2026 00:03:36 -0400
Subject: [PATCH 2/3] changelog

---
 ...pJettySolrClient-IllegalStateException.yml | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml

diff --git a/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml b/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml
new file mode 100644
index 000000000000..ff86548dcde6
--- /dev/null
+++ b/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml
@@ -0,0 +1,33 @@
+# (DELETE ALL COMMENTS UP HERE AFTER FILLING THIS IN
+
+# See https://github.com/apache/solr/blob/main/dev-docs/changelog.adoc
+
+# If the change is minor, don't bother adding a changelog entry.
+# For `other` type entries, the threshold to bother with a changelog entry should be even higher.
+
+# title:
+#  * The audience is end-users and administrators, not committers.
+#  * Be short and focused on the user impact.  Multiple sentences is fine!
+#  * For technical/geeky details, prefer the commit message instead of changelog.
+#  * Reference JIRA issues like `SOLR-12345`, or if no JIRA but have a GitHub PR then `PR#12345`.
+
+# type:
+#  `added` for new features/improvements, opt-in by the user typically documented in the ref guide
+#  `changed` for improvements; not opt-in
+#  `fixed` for improvements that are deemed to have fixed buggy behavior
+#  `deprecated` for marking things deprecated
+#  `removed` for code removed
+#  `dependency_update` for updates to dependencies
+#  `other` for anything else, like large/significant refactorings, build changes,
+#    test infrastructure, or documentation.
+#    Most such changes are too small/minor to bother with a changelog entry.
+
+title: >
+  HttpJettySolrClient could throw IllegalStateException on connection lost,
+  which foiled LBSolrClient's attempts to classify a request as retry-able.
+type: fixed
+authors:
+  - name: David Smiley
+links:
+  - name: PR#4490
+    url: https://github.com/apache/solr/pull/4490

From 045c5c50fc9244162ffe6288294d56e3e52fe422 Mon Sep 17 00:00:00 2001
From: David Smiley <dsmiley@apache.org>
Date: Mon, 1 Jun 2026 00:04:28 -0400
Subject: [PATCH 3/3] changelog

---
 ...pJettySolrClient-IllegalStateException.yml | 24 -------------------
 1 file changed, 24 deletions(-)

diff --git a/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml b/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml
index ff86548dcde6..cf5b8961c987 100644
--- a/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml
+++ b/changelog/unreleased/PR#4490-HttpJettySolrClient-IllegalStateException.yml
@@ -1,27 +1,3 @@
-# (DELETE ALL COMMENTS UP HERE AFTER FILLING THIS IN
-
-# See https://github.com/apache/solr/blob/main/dev-docs/changelog.adoc
-
-# If the change is minor, don't bother adding a changelog entry.
-# For `other` type entries, the threshold to bother with a changelog entry should be even higher.
-
-# title:
-#  * The audience is end-users and administrators, not committers.
-#  * Be short and focused on the user impact.  Multiple sentences is fine!
-#  * For technical/geeky details, prefer the commit message instead of changelog.
-#  * Reference JIRA issues like `SOLR-12345`, or if no JIRA but have a GitHub PR then `PR#12345`.
-
-# type:
-#  `added` for new features/improvements, opt-in by the user typically documented in the ref guide
-#  `changed` for improvements; not opt-in
-#  `fixed` for improvements that are deemed to have fixed buggy behavior
-#  `deprecated` for marking things deprecated
-#  `removed` for code removed
-#  `dependency_update` for updates to dependencies
-#  `other` for anything else, like large/significant refactorings, build changes,
-#    test infrastructure, or documentation.
-#    Most such changes are too small/minor to bother with a changelog entry.
-
 title: >
   HttpJettySolrClient could throw IllegalStateException on connection lost,
   which foiled LBSolrClient's attempts to classify a request as retry-able.