diff --git a/.semaphore/semaphore.yml b/.semaphore/semaphore.yml
index 8f94b3b263..bb8efe4f15 100644
--- a/.semaphore/semaphore.yml
+++ b/.semaphore/semaphore.yml
@@ -18,7 +18,7 @@ global_job_config:
       - mkdir dest
   env_vars:
     - name: CACHE_TAG
-      value: '7'
+      value: '9'
     - name: CI
       value: 'true'
     - name: KAFKA_VERSION
diff --git a/packaging/tools/Dockerfile b/packaging/tools/Dockerfile
index f1c478d287..6ba9a8db17 100644
--- a/packaging/tools/Dockerfile
+++ b/packaging/tools/Dockerfile
@@ -5,7 +5,7 @@ ARG UID
 RUN NEEDRESTART_MODE=a apt-get update && apt-get install -y \
     wget curl python3 git openjdk-21-jdk-headless python3-venv \
     python3-setuptools build-essential libssl-dev libcurl4-openssl-dev \
-    zlib1g-dev libsasl2-dev libzstd-dev clang-format-18 doxygen graphviz
+    zlib1g-dev libsasl2-dev libzstd-dev doxygen graphviz
 
 RUN wget -O rapidjson-dev.deb https://launchpad.net/ubuntu/+archive/primary/+files/rapidjson-dev_1.1.0+dfsg2-3_all.deb && \
     dpkg -i rapidjson-dev.deb && \
diff --git a/packaging/tools/requirements.txt b/packaging/tools/requirements.txt
index 43603098a2..7a96efb13a 100644
--- a/packaging/tools/requirements.txt
+++ b/packaging/tools/requirements.txt
@@ -1,2 +1,3 @@
+clang-format==18.1.8
 flake8
 autopep8
diff --git a/packaging/tools/style-format.sh b/packaging/tools/style-format.sh
index ebd61ad10f..b2c55f82a6 100755
--- a/packaging/tools/style-format.sh
+++ b/packaging/tools/style-format.sh
@@ -6,9 +6,9 @@
 
 
 
-# Requires clang-format version 18  (apt install clang-format-18).
-CLANG_FORMAT=${CLANG_FORMAT:-clang-format-18}
-CLANG_FORMAT_REQUIRED_VERSION=18
+# Requires clang-format version 18 (pip install clang-format==18.1.8).
+CLANG_FORMAT=${CLANG_FORMAT:-clang-format}
+CLANG_FORMAT_REQUIRED_VERSION=18.1.8
 
 set -e
 
@@ -27,9 +27,9 @@ else
     fix=0
 fi
 
-clang_format_version=$(${CLANG_FORMAT} --version | sed -Ee 's/.*version ([[:digit:]]+)\.[[:digit:]]+\.[[:digit:]]+.*/\1/')
+clang_format_version=$(${CLANG_FORMAT} --version | sed -Ee 's/.*version ([[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+).*/\1/')
 if [[ $clang_format_version != "$CLANG_FORMAT_REQUIRED_VERSION" ]] ; then
-    echo "$0: clang-format version ${CLANG_FORMAT_REQUIRED_VERSION}, '$clang_format_version' detected"
+    echo "$0: clang-format version ${CLANG_FORMAT_REQUIRED_VERSION} required, '$clang_format_version' detected"
     exit 1
 fi
 
diff --git a/src/rdhdrhistogram.c b/src/rdhdrhistogram.c
index 08240ac7a3..13016e2065 100644
--- a/src/rdhdrhistogram.c
+++ b/src/rdhdrhistogram.c
@@ -275,8 +275,7 @@ typedef struct rd_hdr_iter_s {
         int64_t highestEquivalentValue;
 } rd_hdr_iter_t;
 
-#define RD_HDR_ITER_INIT(hdr)                                                  \
-        { .hdr = hdr, .subBucketIdx = -1 }
+#define RD_HDR_ITER_INIT(hdr) {.hdr = hdr, .subBucketIdx = -1}
 
 static int rd_hdr_iter_next(rd_hdr_iter_t *it) {
         const rd_hdr_histogram_t *hdr = it->hdr;
diff --git a/src/rdkafka_msg.h b/src/rdkafka_msg.h
index 063fe96b95..32228fe441 100644
--- a/src/rdkafka_msg.h
+++ b/src/rdkafka_msg.h
@@ -230,7 +230,7 @@ typedef struct rd_kafka_msgq_s {
 } rd_kafka_msgq_t;
 
 #define RD_KAFKA_MSGQ_INITIALIZER(rkmq)                                        \
-        { .rkmq_msgs = TAILQ_HEAD_INITIALIZER((rkmq).rkmq_msgs) }
+        {.rkmq_msgs = TAILQ_HEAD_INITIALIZER((rkmq).rkmq_msgs)}
 
 #define RD_KAFKA_MSGQ_FOREACH(elm, head)                                       \
         TAILQ_FOREACH(elm, &(head)->rkmq_msgs, rkm_link)
diff --git a/src/rdkafka_proto.h b/src/rdkafka_proto.h
index 02565ecb3b..f922304c82 100644
--- a/src/rdkafka_proto.h
+++ b/src/rdkafka_proto.h
@@ -281,11 +281,9 @@ typedef struct rd_kafkap_str_s {
 /* strndup() a Kafka string */
 #define RD_KAFKAP_STR_DUP(kstr) rd_strndup((kstr)->str, RD_KAFKAP_STR_LEN(kstr))
 
-#define RD_KAFKAP_STR_INITIALIZER                                              \
-        { .len = RD_KAFKAP_STR_LEN_NULL, .str = NULL }
+#define RD_KAFKAP_STR_INITIALIZER {.len = RD_KAFKAP_STR_LEN_NULL, .str = NULL}
 
-#define RD_KAFKAP_STR_INITIALIZER_EMPTY                                        \
-        { .len = 0, .str = "" }
+#define RD_KAFKAP_STR_INITIALIZER_EMPTY {.len = 0, .str = ""}
 /**
  * Frees a Kafka string previously allocated with `rd_kafkap_str_new()`
  */
@@ -661,8 +659,7 @@ typedef struct rd_kafka_pid_s {
         int16_t epoch; /**< Producer Epoch */
 } rd_kafka_pid_t;
 
-#define RD_KAFKA_PID_INITIALIZER                                               \
-        { -1, -1 }
+#define RD_KAFKA_PID_INITIALIZER {-1, -1}
 
 /**
  * @returns true if \p PID is valid
diff --git a/src/rdsysqueue.h b/src/rdsysqueue.h
index 738cdad792..4e252413f2 100644
--- a/src/rdsysqueue.h
+++ b/src/rdsysqueue.h
@@ -94,8 +94,7 @@
  */
 
 #ifndef TAILQ_HEAD_INITIALIZER
-#define TAILQ_HEAD_INITIALIZER(head)                                           \
-        { NULL, &(head).tqh_first }
+#define TAILQ_HEAD_INITIALIZER(head) {NULL, &(head).tqh_first}
 #endif
 
 #ifndef TAILQ_INSERT_BEFORE
@@ -391,8 +390,7 @@
 #endif
 
 #ifndef SIMPLEQ_HEAD_INITIALIZER
-#define SIMPLEQ_HEAD_INITIALIZER(head)                                         \
-        { NULL, &(head).sqh_first }
+#define SIMPLEQ_HEAD_INITIALIZER(head) {NULL, &(head).sqh_first}
 #endif
 
 #ifndef SIMPLEQ_EMPTY
diff --git a/src/rdwin32.h b/src/rdwin32.h
index 40ea43a7ac..24d88f40dc 100644
--- a/src/rdwin32.h
+++ b/src/rdwin32.h
@@ -231,8 +231,7 @@ static RD_INLINE RD_UNUSED const char *rd_getenv(const char *env,
 /**
  * Empty struct initializer
  */
-#define RD_ZERO_INIT                                                           \
-        { 0 }
+#define RD_ZERO_INIT {0}
 
 #ifndef __cplusplus
 /**
diff --git a/tests/test.c b/tests/test.c
index 51c6e2a293..00d784fa8c 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -100,7 +100,7 @@ static const char *test_states[] = {
 
 #define _TEST_DECL(NAME) extern int main_##NAME(int, char **)
 #define _TEST(NAME, FLAGS, ...)                                                \
-        { .name = #NAME, .mainfunc = main_##NAME, .flags = FLAGS, __VA_ARGS__ }
+        {.name = #NAME, .mainfunc = main_##NAME, .flags = FLAGS, __VA_ARGS__}
 
 
 /**