diff --git a/changelogs/unreleased/hide-show-prompt.md b/changelogs/unreleased/hide-show-prompt.md
new file mode 100644
index 0000000000000000000000000000000000000000..4b153dbf9674d3c2957b28288a461a5a7698f3fe
--- /dev/null
+++ b/changelogs/unreleased/hide-show-prompt.md
@@ -0,0 +1,4 @@
+## feature/lua/console
+
+* Prevent mixing of background print/log output with current user's input in
+ the interactive console (gh-7169).
diff --git a/src/box/lua/console.c b/src/box/lua/console.c
index 9fe0af12003d80e613d037641c621dd788cdd472..d66661b34862a20a678b8298915b79f91e8e8350 100644
--- a/src/box/lua/console.c
+++ b/src/box/lua/console.c
@@ -43,6 +43,7 @@
#include "lua-yaml/lyaml.h"
#include "main.h"
#include "serialize_lua.h"
+#include "say.h"
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
@@ -50,6 +51,8 @@
#include <readline/history.h>
#include <stdlib.h>
#include <ctype.h>
+#include <string.h>
+#include <strings.h>
struct rlist on_console_eval = RLIST_HEAD_INITIALIZER(on_console_eval);
@@ -266,6 +269,192 @@ console_sigint_handler(ev_loop *loop, struct ev_signal *w, int revents)
fiber_wakeup(interactive_fb);
}
+/* {{{ Show/hide prompt */
+
+/*
+ * The idea is borrowed from
+ * https://metacpan.org/dist/AnyEvent-ReadLine-Gnu/source/Gnu.pm
+ */
+
+static char *saved_prompt = NULL;
+static char *saved_line_buffer = NULL;
+static int saved_line_buffer_len = 0;
+static int saved_point = 0;
+
+static int console_hide_prompt_ref = LUA_NOREF;
+static int console_show_prompt_ref = LUA_NOREF;
+
+/**
+ * Don't attempt to hide/show prompt in certain readline states.
+ *
+ * There are readline states, where rl_message() is called
+ * internally. In this case an actual readline's line on the
+ * screen is not prompt + line buffer. Current code can't properly
+ * save and restore the line.
+ */
+static bool
+console_can_hide_show_prompt(void)
+{
+ if (RL_ISSTATE(RL_STATE_NSEARCH))
+ return false;
+ if (RL_ISSTATE(RL_STATE_ISEARCH))
+ return false;
+ if (RL_ISSTATE(RL_STATE_NUMERICARG))
+ return false;
+ return true;
+}
+
+/**
+ * Save and hide readline's output (prompt and current user
+ * input).
+ */
+static void
+console_hide_prompt(void)
+{
+ if (!console_can_hide_show_prompt())
+ return;
+
+ if (rl_prompt == NULL) {
+ saved_prompt = NULL;
+ } else {
+ saved_prompt = xstrdup(rl_prompt);
+ }
+ rl_set_prompt("");
+
+ saved_point = rl_point;
+
+ if (rl_line_buffer == NULL) {
+ saved_line_buffer = NULL;
+ saved_line_buffer_len = 0;
+ } else {
+ saved_line_buffer = xmalloc(rl_end + 1);
+ memcpy(saved_line_buffer, rl_line_buffer, rl_end);
+ saved_line_buffer[rl_end] = '\0';
+ saved_line_buffer_len = rl_end;
+ }
+ rl_replace_line("", 0);
+
+ rl_redisplay();
+}
+
+/**
+ * Show saved readline's output and free saved strings.
+ */
+static void
+console_show_prompt(void)
+{
+ if (!console_can_hide_show_prompt())
+ return;
+
+ rl_set_prompt(saved_prompt);
+ free(saved_prompt);
+ saved_prompt = NULL;
+
+ if (saved_line_buffer == NULL) {
+ rl_replace_line("", 0);
+ } else {
+ rl_replace_line(saved_line_buffer, saved_line_buffer_len);
+ }
+ free(saved_line_buffer);
+ saved_line_buffer = NULL;
+ saved_line_buffer_len = 0;
+
+ rl_point = saved_point;
+ saved_point = 0;
+
+ rl_redisplay();
+}
+
+static int
+lbox_console_hide_prompt(struct lua_State *L)
+{
+ (void)L;
+ console_hide_prompt();
+ return 0;
+}
+
+static int
+lbox_console_show_prompt(struct lua_State *L)
+{
+ (void)L;
+ console_show_prompt();
+ return 0;
+}
+
+/**
+ * Allow to disable hide/show prompt actions using an environment
+ * variable.
+ *
+ * It is not supposed to be a documented variable, but rather just
+ * a way to turn off the feature if something goes wrong.
+ */
+static bool
+console_hide_show_prompt_is_enabled(void)
+{
+ const char *envvar = getenv("TT_CONSOLE_HIDE_SHOW_PROMPT");
+
+ /* Enabled by default. */
+ if (envvar == NULL || *envvar == '\0')
+ return true;
+
+ /* Explicitly enabled or disabled. */
+ if (strcasecmp(envvar, "false") == 0)
+ return false;
+ if (strcasecmp(envvar, "true") == 0)
+ return true;
+
+ /* Accept 0/1 as boolean values. */
+ if (strcmp(envvar, "0") == 0)
+ return false;
+ if (strcmp(envvar, "1") == 0)
+ return true;
+
+ /* Can't parse the value, let's use the default. */
+ return true;
+}
+
+static void
+luaT_console_setup_write_cb(struct lua_State *L)
+{
+ if (!console_hide_show_prompt_is_enabled())
+ return;
+
+ say_set_stderr_callback(console_hide_prompt, console_show_prompt);
+
+ lua_getfield(L, LUA_GLOBALSINDEX, "package");
+ lua_getfield(L, -1, "loaded");
+ lua_getfield(L, -1, "internal.print");
+
+ lua_rawgeti(L, LUA_REGISTRYINDEX, console_hide_prompt_ref);
+ lua_setfield(L, -2, "before_cb");
+ lua_rawgeti(L, LUA_REGISTRYINDEX, console_show_prompt_ref);
+ lua_setfield(L, -2, "after_cb");
+
+ lua_pop(L, 3);
+}
+
+static void
+luaT_console_cleanup_write_cb(struct lua_State *L)
+{
+ if (!console_hide_show_prompt_is_enabled())
+ return;
+
+ say_set_stderr_callback(NULL, NULL);
+
+ lua_getfield(L, LUA_GLOBALSINDEX, "package");
+ lua_getfield(L, -1, "loaded");
+ lua_getfield(L, -1, "internal.print");
+
+ lua_pushnil(L);
+ lua_setfield(L, -2, "before_cb");
+ lua_pushnil(L);
+ lua_setfield(L, -2, "after_cb");
+
+ lua_pop(L, 3);
+}
+
+/* }}} Show/hide prompt */
+
/* implements readline() Lua API */
static int
lbox_console_readline(struct lua_State *L)
@@ -302,6 +491,8 @@ lbox_console_readline(struct lua_State *L)
if (readline_L != NULL)
luaL_error(L, "readline(): earlier call didn't complete yet");
+ luaT_console_setup_write_cb(L);
+
readline_L = L;
if (completion) {
@@ -344,6 +535,8 @@ lbox_console_readline(struct lua_State *L)
lua_pushstring(L, "");
lua_pushboolean(L, sigint_called);
+ luaT_console_cleanup_write_cb(L);
+
readline_L = NULL;
sigint_called = false;
set_sigint_cb(old_cb);
@@ -355,8 +548,10 @@ lbox_console_readline(struct lua_State *L)
* we might spin here forever eating
* the whole cpu time.
*/
- if (fiber_is_cancelled())
+ if (fiber_is_cancelled()) {
+ luaT_console_cleanup_write_cb(L);
set_sigint_cb(old_cb);
+ }
luaL_testcancel(L);
}
rl_callback_read_char();
@@ -366,6 +561,7 @@ lbox_console_readline(struct lua_State *L)
/* Incidents happen. */
#pragma GCC poison readline_L
rl_attempted_completion_function = NULL;
+ luaT_console_cleanup_write_cb(L);
set_sigint_cb(old_cb);
luaL_testcancel(L);
return 2;
@@ -744,6 +940,11 @@ tarantool_lua_console_init(struct lua_State *L)
};
session_vtab_registry[SESSION_TYPE_CONSOLE] = console_session_vtab;
session_vtab_registry[SESSION_TYPE_REPL] = console_session_vtab;
+
+ lua_pushcfunction(L, lbox_console_hide_prompt);
+ console_hide_prompt_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+ lua_pushcfunction(L, lbox_console_show_prompt);
+ console_show_prompt_ref = luaL_ref(L, LUA_REGISTRYINDEX);
}
/*
diff --git a/test/box-luatest/hide_show_prompt_test.lua b/test/box-luatest/hide_show_prompt_test.lua
new file mode 100644
index 0000000000000000000000000000000000000000..eed4d9da1a82e0e586a2997607a132ae8fa60b5b
--- /dev/null
+++ b/test/box-luatest/hide_show_prompt_test.lua
@@ -0,0 +1,57 @@
+local it = require('test.luatest_helpers.interactive_tarantool')
+
+local t = require('luatest')
+local g = t.group()
+
+-- Basic case: prompt is shown and hid.
+--
+-- It does not check that tarantool preserves current input line
+-- and cursor position.
+g.test_basic_print = function()
+ local child = it.new({args = {'-l', 'fiber'}})
+
+ child:execute_command([[
+ _ = fiber.create(function()
+ fiber.name('print_flood', {truncate = true})
+ while true do
+ print('flood')
+ fiber.sleep(0.001)
+ end
+ end)
+ ]])
+ child:assert_empty_response()
+
+ local exp_line = it.PROMPT .. it.CR .. it.ERASE_IN_LINE .. 'flood'
+ for _ = 1, 10 do
+ child:assert_line(exp_line)
+ end
+
+ child:close()
+end
+
+-- The same as the basic case, but prints flood using logger to
+-- stderr.
+--
+-- We don't check for presence of 'flood' lines in the log, but
+-- verify that prompt on stdout is shown and hid.
+g.test_basic_log = function()
+ local child = it.new({args = {'-l', 'fiber', '-l', 'log'}})
+
+ child:execute_command([[
+ _ = fiber.create(function()
+ fiber.name('log_flood', {truncate = true})
+ while true do
+ log.info('flood')
+ fiber.sleep(0.001)
+ end
+ end)
+ ]])
+ child:assert_empty_response()
+
+ local exp_data = it.PROMPT .. it.CR .. it.ERASE_IN_LINE
+ for _ = 1, 10 do
+ child:assert_data(exp_data)
+ end
+
+ child:close()
+end