From 5039d4c5e88268ba386365a9c8f9a2a64a8107d9 Mon Sep 17 00:00:00 2001
From: Bojan Janjatovic <bojan.janjatovic@mamut-studio.com>
Date: Thu, 7 May 2026 18:46:57 +0200
Subject: [PATCH] conf: fix snd_func_imul accumulator initialization

snd_func_iops() initialized result to 0 for both iadd and imul. For
imul this made every multiplication step multiply by 0, so
snd_func_imul() returned 0 for every input since it was added in
aa7a0dd7 (2006-10-11). The doxygen example for imul therefore did not
match observed behavior.

Initialize the accumulator to 1 for imul and keep the empty integers
list result as 0. Add table-driven config tests covering iadd and imul
single, multi, zero, negative, empty, and out-of-order integer lists.

Fixes: https://github.com/alsa-project/alsa-lib/issues/456

Signed-off-by: Bojan Janjatovic <bojan.janjatovic@mamut-studio.com>
---
 src/confmisc.c    |  8 +++++-
 test/lsb/config.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/src/confmisc.c b/src/confmisc.c
index c1f5410c6..4acc3cd69 100644
--- a/src/confmisc.c
+++ b/src/confmisc.c
@@ -488,7 +488,7 @@ static int snd_func_iops(snd_config_t **dst,
 	snd_config_iterator_t i, next;
 	const char *id;
 	char *res = NULL;
-	long result = 0, val;
+	long result = op == 1 ? 1 : 0, val;
 	int idx = 0, err, hit;
 
 	err = snd_config_search(src, "integers", &n);
@@ -531,6 +531,9 @@ static int snd_func_iops(snd_config_t **dst,
 			}
 		}
 	} while (hit);
+	/* Preserve pre-fix behavior for an empty integers list. */
+	if (op == 1 && idx == 0)
+		result = 0;
 	err = snd_config_get_id(src, &id);
 	if (err >= 0)
 		err = snd_config_imake_integer(dst, id, result);
@@ -582,6 +585,9 @@ SND_DLSYM_BUILD_VERSION(snd_func_iadd, SND_CONFIG_DLSYM_VERSION_EVALUATE);
 		integers [ 2 3 2 ]
 	}
 \endcode
+ *
+ * \note An empty \c integers list yields 0 (not the multiplicative
+ *       identity 1) for backward compatibility.
  */
 int snd_func_imul(snd_config_t **dst, snd_config_t *root,
 		  snd_config_t *src, snd_config_t *private_data)
diff --git a/test/lsb/config.c b/test/lsb/config.c
index e8699f138..9906c3559 100644
--- a/test/lsb/config.c
+++ b/test/lsb/config.c
@@ -548,6 +548,74 @@ static void test_for_each(void)
 	ALSA_CHECK(snd_config_delete(c));
 }
 
+static void test_evaluate_integer_functions(void)
+{
+	const char *text =
+		"sum {\n"
+		"	@func iadd\n"
+		"	integers [ 2 3 5 ]\n"
+		"}\n"
+		"product {\n"
+		"	@func imul\n"
+		"	integers [ 2 4 6 ]\n"
+		"}\n"
+		"single {\n"
+		"	@func imul\n"
+		"	integers [ 7 ]\n"
+		"}\n"
+		"with_zero {\n"
+		"	@func imul\n"
+		"	integers [ 2 0 5 ]\n"
+		"}\n"
+		"negative {\n"
+		"	@func imul\n"
+		"	integers [ -2 3 ]\n"
+		"}\n"
+		"empty {\n"
+		"	@func imul\n"
+		"	integers [ ]\n"
+		"}\n"
+		"out_of_order {\n"
+		"	@func imul\n"
+		"	integers {\n"
+		"		2 = 5\n"
+		"		0 = 2\n"
+		"		1 = 3\n"
+		"	}\n"
+		"}\n";
+	struct {
+		const char *id;
+		long result;
+	} *p, expected[] = {
+		{ .id = "sum", .result = 10 },
+		{ .id = "product", .result = 48 },
+		{ .id = "single", .result = 7 },
+		{ .id = "with_zero", .result = 0 },
+		{ .id = "negative", .result = -6 },
+		{ .id = "empty", .result = 0 },
+		{ .id = "out_of_order", .result = 30 },
+		{ .id = NULL, .result = 0 },
+	};
+	snd_config_t *top, *node;
+	snd_input_t *input;
+	long value;
+
+	ALSA_CHECK(snd_input_buffer_open(&input, text, strlen(text)));
+	ALSA_CHECK(snd_config_top(&top));
+	ALSA_CHECK(snd_config_load(top, input));
+	ALSA_CHECK(snd_input_close(input));
+	ALSA_CHECK(snd_config_evaluate(top, top, NULL, NULL));
+
+	for (p = expected; p->id; p++) {
+		ALSA_CHECK(snd_config_search(top, p->id, &node));
+		TEST_CHECK(snd_config_get_type(node) == SND_CONFIG_TYPE_INTEGER);
+		ALSA_CHECK(snd_config_get_integer(node, &value));
+		TEST_CHECK(value == p->result);
+	}
+
+	ALSA_CHECK(snd_config_delete(top));
+}
+
 static int _expand_fcn(snd_config_t **dst, const char *s, void *private_data ATTRIBUTE_UNUSED)
 {
 	if (strcmp(s, "var10") == 0)
@@ -644,6 +712,7 @@ int main(void)
 	test_get_ascii();
 	test_iterators();
 	test_for_each();
+	test_evaluate_integer_functions();
 	test_evaluate_string();
 	test_load_string();
 	return TEST_EXIT_CODE();