check that local register is not edited at the end of macro calls

* This was unsafe and could easily result in crashes, since teco_qreg_current
  would afterwards point to an already freed Q-Register.
* Since automatically editing another register or buffer is not easy to do right,
  we throw an error instead.

5 files changed, 27 insertions, 3 deletions

diff --git a/TODO b/TODO
index c3bbac5..e1d93d7 100644
--- a/TODO
+++ b/TODO
@@ -4,9 +4,6 @@ Tasks:
    "edit" hook.
 
 Known Bugs:
- * A local Q-Register can be left as the edited document
-   even after invoking a macro via <M>.
-   This is probably not safe and we should throw an error instead.
  * E%$...$ broken.
    Similarily EQ$file$ won't do what you would expect it to.
  * <23(1;)> leaves values on the stack and the internal hidden
diff --git a/src/error.h b/src/error.h
index b12ec80..03af66c 100644
--- a/src/error.h
+++ b/src/error.h
@@ -47,6 +47,7 @@ typedef enum {
 	TECO_ERROR_INVALIDQREG,
 	TECO_ERROR_QREGOPUNSUPPORTED,
 	TECO_ERROR_QREGCONTAINSNULL,
+	TECO_ERROR_EDITINGLOCALQREG,
 	TECO_ERROR_MEMLIMIT,
 
 	/** Interrupt current operation */
@@ -127,6 +128,14 @@ teco_error_qregcontainsnull_set(GError **error, const gchar *name, gsize len, gb
 }
 
 static inline void
+teco_error_editinglocalqreg_set(GError **error, const gchar *name, gsize len)
+{
+	g_autofree gchar *name_printable = teco_string_echo(name, len);
+	g_set_error(error, TECO_ERROR, TECO_ERROR_EDITINGLOCALQREG,
+	            "Editing local Q-Register \"%s\" at end of macro call", name_printable);
+}
+
+static inline void
 teco_error_interrupted_set(GError **error)
 {
 	g_set_error_literal(error, TECO_ERROR, TECO_ERROR_INTERRUPTED, "Interrupted");
diff --git a/src/qreg-commands.c b/src/qreg-commands.c
index 8d28e7d..a96eb5f 100644
--- a/src/qreg-commands.c
+++ b/src/qreg-commands.c
@@ -652,8 +652,15 @@ teco_state_macro_got_register(teco_machine_main_t *ctx, teco_qreg_t *qreg,
 	} else {
 		g_auto(teco_qreg_table_t) table;
 		teco_qreg_table_init(&table, FALSE);
+
 		if (!teco_qreg_execute(qreg, &table, error))
 			return NULL;
+		if (teco_qreg_current && !teco_qreg_current->must_undo) {
+			/* currently editing local Q-Register */
+			teco_error_editinglocalqreg_set(error, teco_qreg_current->head.name.data,
+			                                teco_qreg_current->head.name.len);
+			return NULL;
+		}
 	}
 
 	return &teco_state_start;
diff --git a/src/qreg.c b/src/qreg.c
index cac2d12..17b4830 100644
--- a/src/qreg.c
+++ b/src/qreg.c
@@ -1160,6 +1160,12 @@ teco_ed_hook(teco_ed_hook_t type, GError **error)
 
 	if (!teco_qreg_execute(qreg, &locals, error))
 		goto error_add_frame;
+	if (teco_qreg_current && !teco_qreg_current->must_undo) {
+		/* currently editing local Q-Register */
+		teco_error_editinglocalqreg_set(error, teco_qreg_current->head.name.data,
+		                                teco_qreg_current->head.name.len);
+		goto error_add_frame;
+	}
 
 	return teco_expressions_discard_args(error) &&
 	       teco_expressions_brace_close(error);
diff --git a/tests/testsuite.at b/tests/testsuite.at
index e33a2c4..648e76c 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -79,6 +79,11 @@ AT_CHECK([$SCITECO -e "[[a 23Ub ]]b Qb\"N(0/0)'"], 0, ignore, ignore)
 AT_CHECK([$SCITECO -e "[[\$ @FG'..' ]]\$ :Q\$-1Q\$-^^r\"=(0/0)'"], 0, ignore, ignore)
 AT_CLEANUP
 
+AT_SETUP([Editing local registers in macro calls])
+AT_CHECK([$SCITECO -e '@^Ua{@EQ.x//} :Ma @^U.x/FOO/'], 0, ignore, ignore)
+AT_CHECK([$SCITECO -e '@^Ua{@EQ.x//}  Ma @^U.x/FOO/'], 1, ignore, ignore)
+AT_CLEANUP
+
 AT_SETUP([8-bit cleanliness])
 AT_CHECK([$SCITECO -e "0@I//J 0A\"N(0/0)' :@S/^@/\"F(0/0)'"], 0, ignore, ignore)
 AT_CHECK([$SCITECO -e "@EQa//0EE 1U*0EE 0:@EUa/f^@^@/ :Qa-4\"N(0/0)' Ga Z-4\"N(0/0)'"], 0, ignore, ignore)