Aggressively use actual func params in verror

PHP errors used to not show parameter info consistently.
Make it so that it uses a backtrace to get function info, similar to how
exceptions work.

This makes the docref error functions' parameter argument mostly
vestigal, being used only if allocation fails basically.

Several tests will fail from the fact we include function params.
One annoyance is that _build_trace_args truncates strings according to
exception_string_param_max_len.

See GH-12048

Author: NattyNarwhal

Zend/zend_exceptions.c

@@ -587,6 +587,39 @@ static void _build_trace_string(smart_str *str, HashTable *ht, uint32_t num) /*
 }
 /* }}} */
 
+ZEND_API zend_string *zend_trace_function_args_to_string(HashTable *frame) {
+	zval *tmp;
+	smart_str str = {0};
+	/* init because ASan will complain */
+	smart_str_appends(&str, "");
+
+	tmp = zend_hash_find_known_hash(frame, ZSTR_KNOWN(ZEND_STR_ARGS));
+	if (tmp) {
+		if (Z_TYPE_P(tmp) == IS_ARRAY) {
+			size_t last_len = ZSTR_LEN(str.s);
+			zend_string *name;
+			zval *arg;
+
+			ZEND_HASH_FOREACH_STR_KEY_VAL(Z_ARRVAL_P(tmp), name, arg) {
+				if (name) {
+					smart_str_append(&str, name);
+					smart_str_appends(&str, ": ");
+				}
+				_build_trace_args(arg, &str);
+			} ZEND_HASH_FOREACH_END();
+
+			if (last_len != ZSTR_LEN(str.s)) {
+				ZSTR_LEN(str.s) -= 2; /* remove last ', ' */
+			}
+		} else {
+			smart_str_appends(&str, "<<invalid argument array>>");
+		}
+	}
+
+	smart_str_0(&str);
+	return str.s ? str.s : ZSTR_EMPTY_ALLOC();
+}
+
 ZEND_API zend_string *zend_trace_to_string(HashTable *trace, bool include_main) {
 	zend_ulong index;
 	zval *frame;

Zend/zend_exceptions.h

@@ -69,6 +69,7 @@ extern ZEND_API void (*zend_throw_exception_hook)(zend_object *ex);
 /* show an exception using zend_error(severity,...), severity should be E_ERROR */
 ZEND_API ZEND_COLD zend_result zend_exception_error(zend_object *exception, int severity);
 ZEND_NORETURN void zend_exception_uncaught_error(const char *prefix, ...) ZEND_ATTRIBUTE_FORMAT(printf, 1, 2);
+ZEND_API zend_string *zend_trace_function_args_to_string(HashTable *frame);
 ZEND_API zend_string *zend_trace_to_string(HashTable *trace, bool include_main);
 
 ZEND_API ZEND_COLD zend_object *zend_create_unwind_exit(void);

main/main.c

@@ -57,6 +57,7 @@
 #include "ext/standard/flock_compat.h"
 #endif
 #include "php_syslog.h"
+#include "Zend/zend_builtin_functions.h"
 #include "Zend/zend_exceptions.h"
 
 #if PHP_SIGCHILD
@@ -936,6 +937,26 @@ static zend_string *escape_html(const char *buffer, size_t buffer_len) {
 	return result;
 }
 
+static zend_string *build_dynamic_parameters(void) {
+	zend_string *dynamic_params = NULL;
+	/* get a backtrace to snarf function args */
+	zval backtrace, *first_frame;
+	zend_fetch_debug_backtrace(&backtrace, /* skip_last */ 0, /* options */ 0, /* limit */ 1);
+	/* can fail esp if low memory condition */
+	if (Z_TYPE(backtrace) != IS_ARRAY) {
+		return NULL; /* don't need to free */
+	}
+	first_frame = zend_hash_index_find(Z_ARRVAL(backtrace), 0);
+	if (!first_frame) {
+		goto free_backtrace;
+	}
+	dynamic_params = zend_trace_function_args_to_string(Z_ARRVAL_P(first_frame));
+free_backtrace:
+	zval_ptr_dtor(&backtrace);
+	/* free the string after we use it */
+	return dynamic_params;
+}
+
 /* {{{ php_verror */
 /* php_verror is called from php_error_docref<n> functions.
  * Its purpose is to unify error messages and automatically generate clickable
@@ -1021,7 +1042,12 @@ PHPAPI ZEND_COLD void php_verror(const char *docref, const char *params, int typ
 
 	/* if we still have memory then format the origin */
 	if (is_function) {
-		origin_len = (int)spprintf(&origin, 0, "%s%s%s(%s)", class_name, space, function, params);
+		zend_string *dynamic_params = NULL;
+		dynamic_params = build_dynamic_parameters();
+		origin_len = (int)spprintf(&origin, 0, "%s%s%s(%s)", class_name, space, function, dynamic_params ? ZSTR_VAL(dynamic_params) : params);
+		if (dynamic_params) {
+			zend_string_release(dynamic_params);
+		}
 	} else {
 		origin_len = (int)spprintf(&origin, 0, "%s", function);
 	}