From 627db4d751bc2e583f0800be0856a3cfb2aaf67b Mon Sep 17 00:00:00 2001
From: Alexey Zatelepin <ztlpn@redpanda.com>
Date: Fri, 10 May 2024 15:35:27 +0200
Subject: [PATCH] utils: introduce concurrent_modification_error exception

It is handy to have a base class for all instances of concurrent
modifications.
---
 src/v/cluster/topic_table.h           | 13 ++++-------
 src/v/cluster/topics_frontend.cc      |  2 +-
 src/v/utils/exceptions.h              | 33 +++++++++++++++++++++++++++
 src/v/utils/stable_iterator_adaptor.h | 10 ++++----
 4 files changed, 43 insertions(+), 15 deletions(-)
 create mode 100644 src/v/utils/exceptions.h

diff --git a/src/v/cluster/topic_table.h b/src/v/cluster/topic_table.h
index 92bf4b70f5c3a..558e762e59198 100644
--- a/src/v/cluster/topic_table.h
+++ b/src/v/cluster/topic_table.h
@@ -94,22 +94,17 @@ class topic_table {
     //   * partition::get_revision_id()
     //   * raft::group_configuration::revision_id()
 
-    class concurrent_modification_error final : public std::exception {
+    class concurrent_modification_error final
+      : public ::concurrent_modification_error {
     public:
         concurrent_modification_error(
           model::revision_id initial_revision,
           model::revision_id current_revision)
-          : _msg(ssx::sformat(
+          : ::concurrent_modification_error(ssx::sformat(
             "Topic table was modified by concurrent fiber. "
-            "(initial_revision: "
-            "{}, current_revision: {}) ",
+            "(initial_revision: {}, current_revision: {}) ",
             initial_revision,
             current_revision)) {}
-
-        const char* what() const noexcept final { return _msg.c_str(); }
-
-    private:
-        ss::sstring _msg;
     };
 
     class in_progress_update {
diff --git a/src/v/cluster/topics_frontend.cc b/src/v/cluster/topics_frontend.cc
index a100e95c9eb17..26749601066a5 100644
--- a/src/v/cluster/topics_frontend.cc
+++ b/src/v/cluster/topics_frontend.cc
@@ -1014,7 +1014,7 @@ topics_frontend::partitions_with_lost_majority(
             co_return errc::concurrent_modification_error;
         }
         co_return result;
-    } catch (const topic_table::concurrent_modification_error& e) {
+    } catch (const concurrent_modification_error& e) {
         // state changed while generating the plan, force caller to retry;
         vlog(
           clusterlog.info,
diff --git a/src/v/utils/exceptions.h b/src/v/utils/exceptions.h
new file mode 100644
index 0000000000000..f8289206d2fa1
--- /dev/null
+++ b/src/v/utils/exceptions.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2024 Redpanda Data, Inc.
+ *
+ * Use of this software is governed by the Business Source License
+ * included in the file licenses/BSL.md
+ *
+ * As of the Change Date specified in that file, in accordance with
+ * the Business Source License, use of this software will be governed
+ * by the Apache License, Version 2.0
+ */
+#pragma once
+
+#include "base/seastarx.h"
+
+#include <seastar/core/sstring.hh>
+
+#include <stdexcept>
+
+/// Some objects reference state that changes comparatively rarely (e.g.
+/// topic_table state) across yield points and expect these references to remain
+/// valid. In case these references are invalidated by a concurrent fiber, this
+/// exception is thrown. This is a signal for the caller to restart the
+/// computation with up-to-date state.
+class concurrent_modification_error : public std::exception {
+public:
+    explicit concurrent_modification_error(ss::sstring s)
+      : _msg(std::move(s)) {}
+
+    const char* what() const noexcept override { return _msg.c_str(); }
+
+private:
+    ss::sstring _msg;
+};
diff --git a/src/v/utils/stable_iterator_adaptor.h b/src/v/utils/stable_iterator_adaptor.h
index cfde5ec4d47ff..0e93cbace1227 100644
--- a/src/v/utils/stable_iterator_adaptor.h
+++ b/src/v/utils/stable_iterator_adaptor.h
@@ -11,20 +11,20 @@
 #pragma once
 
 #include "base/seastarx.h"
+#include "utils/exceptions.h"
 
 #include <seastar/util/noncopyable_function.hh>
 
 #include <boost/iterator/iterator_adaptor.hpp>
 #include <fmt/format.h>
 
-#include <stdexcept>
-#include <string_view>
 #include <version>
 
-class iterator_stability_violation : public std::runtime_error {
+class iterator_stability_violation final
+  : public concurrent_modification_error {
 public:
-    explicit iterator_stability_violation(const std::string& why)
-      : std::runtime_error(why){};
+    explicit iterator_stability_violation(ss::sstring why)
+      : concurrent_modification_error(std::move(why)){};
 };
 
 /*