Merge branch 'feat/ota-branch-switch' into merge/ota-branch-into-observer-firmware-dev

src/helpers/OtaChannel.h

@@ -117,11 +117,13 @@ static inline bool ota_compat_parse(const char* s, OtaCompat* out) {
 }
 
 // Find the tag in an image chunk; returns the NUL-terminated value text, or nullptr when
-// the chunk holds no complete tag.
+// the chunk holds no complete tag. Skips the bare OTA_COMPAT_TAG search literal, which
+// every image also contains.
 static inline const char* ota_compat_find(const uint8_t* buf, size_t len) {
   const size_t tag_len = sizeof(OTA_COMPAT_TAG) - 1;
   for (size_t i = 0; i + tag_len < len; i++) {
     if (memcmp(buf + i, OTA_COMPAT_TAG, tag_len) != 0) continue;
+    if (buf[i + tag_len] < '0' || buf[i + tag_len] > '9') continue;
     if (memchr(buf + i + tag_len, 0, len - i - tag_len)) return (const char*)buf + i + tag_len;
   }
   return nullptr;

test/test_ota_channel/test_ota_channel.cpp

@@ -62,6 +62,10 @@ TEST(OtaCompat, FindsCompleteTagOnly) {
   EXPECT_STREQ(v, "2+eth");
   const char cut[] = "junk ota-compat:2+e";  // value runs past the chunk end
   EXPECT_EQ(ota_compat_find((const uint8_t*)cut, sizeof(cut) - 1), nullptr);
+  const char literal_first[] = "ota-compat:\0code\0ota-compat:1\0";  // search literal precedes the tag
+  v = ota_compat_find((const uint8_t*)literal_first, sizeof(literal_first));
+  ASSERT_NE(v, nullptr);
+  EXPECT_STREQ(v, "1");
   const char none[] = "ota-compat";
   EXPECT_EQ(ota_compat_find((const uint8_t*)none, sizeof(none)), nullptr);
 }