From 5927f6a5e1847ba99481cf787fc4031834db5f61 Mon Sep 17 00:00:00 2001
From: Hojun-Cho <ghwns6743@gmail.com>
Date: Wed, 12 Aug 2026 16:21:33 +0900
Subject: [PATCH] fix: forward input at the composition limit

---
 strans.c            |  4 +++-
 tests/engine_test.c | 30 ++++++++++++++++++++++++++++++
 tests/test.h        |  1 +
 tests/unit_test.c   |  1 +
 4 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/strans.c b/strans.c
index 26efc2c..b47a609 100644
--- a/strans.c
+++ b/strans.c
@@ -718,8 +718,10 @@ keystroke(u32int ks, u32int mod, Str *com)
 		if(!haspre(&im))
 			return 0;
 		commit(com);
-		sputr(com, ks);
 		reset();
+		if(com->n >= Maxrunes)
+			return 0;
+		sputr(com, ks);
 		return 1;
 	}
 	if(im.l->trans == nil)
diff --git a/tests/engine_test.c b/tests/engine_test.c
index 246ae2f..88542dc 100644
--- a/tests/engine_test.c
+++ b/tests/engine_test.c
@@ -1280,3 +1280,33 @@ engine_randomized_stress(struct ct *t)
 	emojiend(&f);
 	vi->map = vimap;
 }
+
+void
+engine_full_boundary_passthrough(struct ct *t)
+{
+	Str com;
+	int i;
+
+	init();
+	im.l = getlang(LangJP);
+	for(i = 0; i < Maxrunes; i++)
+		im.pre.r[i] = L'あ';
+	im.pre.n = Maxrunes;
+	sclear(&com);
+	CT_CHECK(t, !keystroke(' ', 0, &com));
+	CT_EQ_INT(t, Maxrunes, com.n);
+	for(i = 0; i < Maxrunes; i++)
+		CT_EQ_UINT(t, L'あ', com.r[i]);
+	CT_EQ_INT(t, 0, im.pre.n);
+	CT_EQ_INT(t, 0, im.raw.n);
+
+	init();
+	im.l = getlang(LangJP);
+	for(i = 0; i < Maxrunes-1; i++)
+		im.pre.r[i] = L'あ';
+	im.pre.n = Maxrunes-1;
+	sclear(&com);
+	CT_CHECK(t, keystroke(' ', 0, &com));
+	CT_EQ_INT(t, Maxrunes, com.n);
+	CT_EQ_UINT(t, ' ', com.r[Maxrunes-1]);
+}
diff --git a/tests/test.h b/tests/test.h
index bff84af..107b207 100644
--- a/tests/test.h
+++ b/tests/test.h
@@ -61,6 +61,7 @@ void	engine_emoji_preedit_languages(struct ct*);
 void	engine_emoji_start_and_unknown(struct ct*);
 void	engine_emoji_dictionary_identity(struct ct*);
 void	engine_randomized_stress(struct ct*);
+void	engine_full_boundary_passthrough(struct ct*);
 void	dictionary_candidates(struct ct*);
 void	dictionary_misses_clear_result(struct ct*);
 void	dictionary_emoji_identity(struct ct*);
diff --git a/tests/unit_test.c b/tests/unit_test.c
index 508df79..64e6fc8 100644
--- a/tests/unit_test.c
+++ b/tests/unit_test.c
@@ -110,6 +110,7 @@ static const struct ct_test tests[] = {
 	{ "engine/emoji-start-and-unknown", engine_emoji_start_and_unknown },
 	{ "engine/emoji-dictionary-identity", engine_emoji_dictionary_identity },
 	{ "engine/randomized-stress", engine_randomized_stress },
+	{ "engine/full-boundary-passthrough", engine_full_boundary_passthrough },
 	{ "dict/candidates", dictionary_candidates },
 	{ "dict/misses-clear-result", dictionary_misses_clear_result },
 	{ "dict/emoji-identity", dictionary_emoji_identity },