pyln-testing: use DEBUG_LIGHTNINGD to start gdb on lightningd during test.

We do this for DEBUG_SUBD already, but I wanted to debug the main lightningd.

(We rename --debugger to the more accurate --dev-debug-self)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/daemon.c

@@ -196,7 +196,7 @@ bool daemon_developer_mode(char *argv[])
 	bool developer = false, debug = false;
 
 	for (int i = 1; argv[i]; i++) {
-		if (streq(argv[i], "--debugger"))
+		if (streq(argv[i], "--dev-debug-self"))
 			debug = true;
 		else if (streq(argv[i], "--developer"))
 			developer = true;

common/daemon.h

@@ -22,7 +22,7 @@ const char *backtrace_symname(const tal_t *ctx, const void *addr);
 void daemon_shutdown(void);
 
 /* If --developer is set, set up extra developer checks, kick in a
- * debugger if they set --debugger, and return true.   */
+ * debugger if they set --dev-debug-self, and return true.   */
 bool daemon_developer_mode(char *argv[]);
 
 #endif /* LIGHTNING_COMMON_DAEMON_H */

contrib/pyln-testing/pyln/testing/utils.py

@@ -789,6 +789,8 @@ class LightningNode(object):
             self.daemon.opts["dev-no-version-checks"] = None
         if os.getenv("DEBUG_SUBD"):
             self.daemon.opts["dev-debugger"] = os.getenv("DEBUG_SUBD")
+        if os.getenv("DEBUG_LIGHTNINGD"):
+            self.daemon.opts["dev-debug-self"] = None
         if valgrind:
             self.daemon.env["LIGHTNINGD_DEV_NO_BACKTRACE"] = "1"
             self.daemon.opts["dev-no-plugin-checksum"] = None

doc/contribute-to-core-lightning/testing.md

@@ -41,7 +41,7 @@ There are four kinds of tests:
 
   `PYTHONPATH=contrib/pyln-client:contrib/pyln-testing:contrib/pyln-proto:contrib/pyln-grpc-proto py.test -v tests/`
 
-  You can also append `-k TESTNAME` to run a single test.  Environment variables `DEBUG_SUBD=<subdaemon>` and `TIMEOUT=<seconds>` can be useful for debugging subdaemons on individual tests.
+  You can also append `-k TESTNAME` to run a single test.  Environment variables `DEBUG_SUBD=<subdaemon>` and `TIMEOUT=<seconds>` can be useful for debugging subdaemons on individual tests, and `DEBUG_LIGHTNINGD` for attaching a debugger to each `lightningd` instance created.
 
 - **pylightning tests** - will check contrib pylightning for codestyle and run the tests in `contrib/pylightning/tests` afterwards:
 

lightningd/lightningd.c

@@ -1068,6 +1068,12 @@ int main(int argc, char *argv[])
 
 	trace_span_start("lightningd/startup", argv);
 
+	/*~ What happens in strange locales should stay there. */
+	setup_locale();
+
+	/*~ This handles --dev-debug-self really early, which we otherwise ignore */
+	daemon_developer_mode(argv);
+
 	/*~ We fork out new processes very very often; every channel gets its
 	 * own process, for example, and we have `hsmd` and `gossipd` and
 	 * the plugins as well.
@@ -1106,9 +1112,6 @@ int main(int argc, char *argv[])
 	 */
 	closefrom_limit(4096);
 
-	/*~ What happens in strange locales should stay there. */
-	setup_locale();
-
 	/*~ This sets up SIGCHLD to make sigchld_rfd readable. */
 	sigchld_rfd = setup_sig_handlers();
 

lightningd/options.c

@@ -784,6 +784,11 @@ static char *opt_force_featureset(const char *optarg,
 	return NULL;
 }
 
+static char *opt_ignore(void *unused)
+{
+	return NULL;
+}
+
 static void dev_register_opts(struct lightningd *ld)
 {
 	/* We might want to debug plugins, which are started before normal
@@ -915,6 +920,11 @@ static void dev_register_opts(struct lightningd *ld)
 		     opt_set_bool,
 		     &ld->dev_allow_shutdown_destination_change,
 		     "Allow destination override on close, even if risky");
+	/* This is handled directly in daemon_developer_mode(), so we ignore it here */
+	clnopt_noarg("--dev-debug-self", OPT_DEV,
+		     opt_ignore,
+		     NULL,
+		     "Fire up a terminal window with a debugger in it on initialization");
 }
 
 static const struct config testnet_config = {

lightningd/plugin.c

@@ -1985,7 +1985,7 @@ const char *plugin_send_getmanifest(struct plugin *p, const char *cmd_id)
 	cmd = tal_arr(tmpctx, char *, 1);
 	cmd[0] = p->cmd;
 	if (debugging(p))
-		tal_arr_expand(&cmd, "--debugger");
+		tal_arr_expand(&cmd, "--dev-debug-self");
 	if (p->plugins->ld->developer)
 		tal_arr_expand(&cmd, "--developer");
 	tal_arr_expand(&cmd, NULL);

lightningd/subd.c

@@ -258,7 +258,7 @@ static int subd(const char *path, const char *name,
 		if (io_logging)
 			args[num_args++] = "--log-io";
 		if (debugging)
-			args[num_args++] = "--debugger";
+			args[num_args++] = "--dev-debug-self";
 		if (developer)
 			args[num_args++] = "--developer";
 		execv(args[0], args);

lightningd/test/run-find_my_abspath.c

@@ -27,6 +27,9 @@ int connectd_init(struct lightningd *ld UNNEEDED)
 /* Generated stub for connectd_start_shutdown */
 void connectd_start_shutdown(struct subd *connectd UNNEEDED)
 { fprintf(stderr, "connectd_start_shutdown called!\n"); abort(); }
+/* Generated stub for daemon_developer_mode */
+bool daemon_developer_mode(char *argv[])
+{ fprintf(stderr, "daemon_developer_mode called!\n"); abort(); }
 /* Generated stub for daemon_poll */
 int daemon_poll(struct pollfd *fds UNNEEDED, nfds_t nfds UNNEEDED, int timeout UNNEEDED)
 { fprintf(stderr, "daemon_poll called!\n"); abort(); }