Add FUNCTION FLUSH command to flush all functions (#9936)

Added `FUNCTION FLUSH` command. The new sub-command allows delete all the functions.
An optional `[SYNC|ASYNC]` argument can be given to control whether or not to flush the
functions synchronously or asynchronously. if not given the default flush mode is chosen by
`lazyfree-lazy-user-flush` configuration values.

Add the missing `functions.tcl` test to the list of tests that are executed in test_helper.tcl,
and call FUNCTION FLUSH in between servers in external mode

3 files changed, 43 insertions, 1 deletions

diff --git a/tests/support/server.tcl b/tests/support/server.tcl
index 4c63d7b3a..ee39c8df9 100644
--- a/tests/support/server.tcl
+++ b/tests/support/server.tcl
@@ -343,6 +343,7 @@ proc run_external_server_test {code overrides} {
     }
 
     r flushall
+    r function flush
 
     # store overrides
     set saved_config {}
diff --git a/tests/test_helper.tcl b/tests/test_helper.tcl
index d1405e3e3..570d9e85f 100644
--- a/tests/test_helper.tcl
+++ b/tests/test_helper.tcl
@@ -63,6 +63,7 @@ set ::all_tests {
     unit/pubsub
     unit/slowlog
     unit/scripting
+    unit/functions
     unit/maxmemory
     unit/introspection
     unit/introspection-2
diff --git a/tests/unit/functions.tcl b/tests/unit/functions.tcl
index 0736a44da..27bb29b72 100644
--- a/tests/unit/functions.tcl
+++ b/tests/unit/functions.tcl
@@ -185,9 +185,34 @@ start_server {tags {"scripting"}} {
         after 200 ; # Give some time to Lua to call the hook again...
         assert_equal [r ping] "PONG"
     }
+
+    test {FUNCTION - test function flush} {
+        r function create lua test REPLACE {local a = 1 while true do a = a + 1 end}
+        assert_match {{name test engine LUA description {}}} [r function list]
+        r function flush
+        assert_match {} [r function list]
+
+        r function create lua test REPLACE {local a = 1 while true do a = a + 1 end}
+        assert_match {{name test engine LUA description {}}} [r function list]
+        r function flush async
+        assert_match {} [r function list]
+
+        r function create lua test REPLACE {local a = 1 while true do a = a + 1 end}
+        assert_match {{name test engine LUA description {}}} [r function list]
+        r function flush sync
+        assert_match {} [r function list]
+    }
+
+    test {FUNCTION - test function wrong argument} {
+        catch {r function flush bad_arg} e
+        assert_match {*only supports SYNC|ASYNC*} $e
+
+        catch {r function flush sync extra_arg} e
+        assert_match {*wrong number of arguments*} $e
+    }
 }
 
-start_server {tags {"scripting repl"}} {
+start_server {tags {"scripting repl external:skip"}} {
     start_server {} {
         test "Connect a replica to the master instance" {
             r -1 slaveof [srv 0 host] [srv 0 port]
@@ -221,6 +246,21 @@ start_server {tags {"scripting repl"}} {
             }
         }
 
+        test {FUNCTION - flush is replicated to replica} {
+            r function create LUA test DESCRIPTION {some description} {return 'hello'}
+            wait_for_condition 50 100 {
+                [r -1 function list] eq {{name test engine LUA description {some description}}}
+            } else {
+                fail "Failed waiting for function to replicate to replica"
+            }
+            r function flush
+            wait_for_condition 50 100 {
+                [r -1 function list] eq {}
+            } else {
+                fail "Failed waiting for function to replicate to replica"
+            }
+        }
+
         test "Disconnecting the replica from master instance" {
             r -1 slaveof no one
             # creating a function after disconnect to make sure function