diff --git a/core/error/SCsub b/core/error/SCsub
index dfd6248a941c..eb95be1f6184 100644
--- a/core/error/SCsub
+++ b/core/error/SCsub
@@ -4,4 +4,7 @@ Import("env")
 
 env_error = env.Clone()
 
+if env["tests"]:
+    env_error.Append(CPPDEFINES=["TESTS_ENABLED"])
+
 env_error.add_source_files(env.core_sources, "*.cpp")
diff --git a/core/error/error_macros.cpp b/core/error/error_macros.cpp
index 8376c0aaf84c..e0331f06e430 100644
--- a/core/error/error_macros.cpp
+++ b/core/error/error_macros.cpp
@@ -83,6 +83,29 @@ void _err_print_error(const char *p_function, const char *p_file, int p_line, co
 
 // Main error printing function.
 void _err_print_error(const char *p_function, const char *p_file, int p_line, const char *p_error, const char *p_message, bool p_editor_notify, ErrorHandlerType p_type) {
+#ifndef TESTS_ENABLED
+	_global_lock();
+	// Eliminate duplicate errors to stop locking up the editor due to spam.
+	static int prev_line = INT_MAX;
+	static uint32_t prev_frame = UINT32_MAX;
+	static CharString prev_function;
+	static CharString prev_file;
+	static CharString prev_error;
+
+	// Only de-duplicate on the current frame.
+	uint32_t curr_frame = Engine::get_singleton()->get_process_frames();
+	if ((prev_frame == curr_frame) && (prev_line == p_line) && (prev_function == p_function) && (prev_file == p_file) && (prev_error == p_error)) {
+		_global_unlock();
+		return;
+	}
+	prev_function = p_function;
+	prev_file = p_file;
+	prev_line = p_line;
+	prev_error = p_error;
+	prev_frame = curr_frame;
+	_global_unlock();
+#endif
+
 	if (OS::get_singleton()) {
 		OS::get_singleton()->print_error(p_function, p_file, p_line, p_error, p_message, p_editor_notify, (Logger::ErrorType)p_type);
 	} else {
diff --git a/core/error/error_macros.h b/core/error/error_macros.h
index c8182975d57b..44d36ec9507f 100644
--- a/core/error/error_macros.h
+++ b/core/error/error_macros.h
@@ -100,6 +100,10 @@ void _err_flush_stdout();
  * Always try to return processable data, so the engine can keep running well.
  * Use the _MSG versions to print a meaningful message to help with debugging.
  *
+ * NOTE: Error and warning messages are deduplicated on a per-frame basis, to prevent
+ * spam. If you wish to output multiple similar errors / warnings, be sure to differentiate them.
+ * See _err_print_error().
+ *
  * The `((void)0)` no-op statement is used as a trick to force us to put a semicolon after
  * those macros, making them look like proper statements.
  * The if wrappers are used to ensure that the macro replacement does not trigger unexpected
diff --git a/core/string/ustring.cpp b/core/string/ustring.cpp
index 60e2d539f88d..b2da3edd29ae 100644
--- a/core/string/ustring.cpp
+++ b/core/string/ustring.cpp
@@ -162,6 +162,16 @@ bool CharString::operator<(const CharString &p_right) const {
 	return is_str_less(get_data(), p_right.get_data());
 }
 
+bool CharString::operator==(const char *p_right) const {
+	// nullptr and null terminator translate to the same CharString, length 0.
+	if (p_right == nullptr || p_right[0] == 0) {
+		return length() == 0;
+	} else if (length() == 0) {
+		return false;
+	}
+	return strcmp(ptr(), p_right) == 0;
+}
+
 bool CharString::operator==(const CharString &p_right) const {
 	if (length() == 0) {
 		// True if both have length 0, false if only p_right has a length
diff --git a/core/string/ustring.h b/core/string/ustring.h
index 897b06fc6dc6..1bb40eacd974 100644
--- a/core/string/ustring.h
+++ b/core/string/ustring.h
@@ -157,6 +157,7 @@ class CharString {
 	void operator=(const char *p_cstr);
 	bool operator<(const CharString &p_right) const;
 	bool operator==(const CharString &p_right) const;
+	bool operator==(const char *p_right) const;
 	CharString &operator+=(char p_char);
 	int length() const { return size() ? size() - 1 : 0; }
 	const char *get_data() const;