summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAlex Orlenko <zxteam@protonmail.com>2021-05-09 21:39:28 +0100
committerAlex Orlenko <zxteam@protonmail.com>2021-05-10 17:45:00 +0100
commit35b75040768571e57f722b9ad4d75b2986cbee6e (patch)
tree93b26d3645e40c65e1fd1c9fe2c02c54103a4a1e
parentc9b8eb5418d942ac3b5516a9626f0f029c14b80c (diff)
downloadmlua-35b75040768571e57f722b9ad4d75b2986cbee6e.zip
Improve error reporting in module mode.
Attach traceback to a WrappedError. Fixes #44.
-rw-r--r--src/error.rs2
-rw-r--r--src/ffi/compat53.rs2
-rw-r--r--src/ffi/shim/shim.c43
-rw-r--r--src/util.rs94
4 files changed, 86 insertions, 55 deletions
diff --git a/src/error.rs b/src/error.rs
index 639cab9..652fa74 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -248,7 +248,7 @@ impl fmt::Display for Error {
write!(fmt, "RegistryKey used from different Lua state")
}
Error::CallbackError { ref traceback, .. } => {
- write!(fmt, "callback error: {}", traceback)
+ write!(fmt, "callback error\n{}", traceback)
}
Error::PreviouslyResumedPanic => {
write!(fmt, "previously resumed panic returned again")
diff --git a/src/ffi/compat53.rs b/src/ffi/compat53.rs
index 3d8af28..f4a2a01 100644
--- a/src/ffi/compat53.rs
+++ b/src/ffi/compat53.rs
@@ -680,7 +680,7 @@ pub unsafe fn luaL_traceback(
msg: *const c_char,
mut level: c_int,
) {
- let mut ar: lua_Debug = std::mem::zeroed();
+ let mut ar: lua_Debug = mem::zeroed();
let top = lua_gettop(L);
let numlevels = compat53_countlevels(L1);
let mark = if numlevels > COMPAT53_LEVELS1 + COMPAT53_LEVELS2 {
diff --git a/src/ffi/shim/shim.c b/src/ffi/shim/shim.c
index 6309970..2ed2ec7 100644
--- a/src/ffi/shim/shim.c
+++ b/src/ffi/shim/shim.c
@@ -31,13 +31,18 @@ size_t MLUA_WRAPPED_PANIC_SIZE = 0;
const void *MLUA_WRAPPED_ERROR_KEY = NULL;
const void *MLUA_WRAPPED_PANIC_KEY = NULL;
-extern void wrapped_error_traceback(lua_State *L, int error_idx, void *error_ud,
- int has_traceback);
+extern void wrapped_error_traceback(lua_State *L, int error_idx,
+ int traceback_idx,
+ int convert_to_callback_error);
extern int mlua_hook_proc(lua_State *L, lua_Debug *ar);
#define max(a, b) (a > b ? a : b)
+// I believe luaL_traceback < 5.4 requires this much free stack to not error.
+// 5.4 uses luaL_Buffer
+const int LUA_TRACEBACK_STACK = 11;
+
typedef struct {
const char *data;
size_t len;
@@ -67,7 +72,15 @@ static int lua_call_rust(lua_State *L) {
lua_CFunction rust_callback = lua_touserdata(L, lua_upvalueindex(1));
int ret = rust_callback(L);
- if (ret == -1) {
+ if (ret < 0) {
+ if (ret == -1 /* WrappedError */) {
+ if (lua_checkstack(L, LUA_TRACEBACK_STACK) != 0) {
+ luaL_traceback(L, L, NULL, 0);
+ // Attach traceback
+ wrapped_error_traceback(L, -2, -1, 0);
+ lua_pop(L, 1);
+ }
+ }
lua_error(L);
}
@@ -401,10 +414,6 @@ int is_wrapped_struct(lua_State *state, int index, const void *key) {
// rust errors under certain memory conditions. This function ensures that such
// behavior will *never* occur with a rust panic, however.
int error_traceback(lua_State *state) {
- // I believe luaL_traceback < 5.4 requires this much free stack to not error.
- // 5.4 uses luaL_Buffer
- const int LUA_TRACEBACK_STACK = 11;
-
if (lua_checkstack(state, 2) == 0) {
// If we don't have enough stack space to even check the error type, do
// nothing so we don't risk shadowing a rust panic.
@@ -412,24 +421,18 @@ int error_traceback(lua_State *state) {
}
if (is_wrapped_struct(state, -1, MLUA_WRAPPED_ERROR_KEY) != 0) {
- int error_idx = lua_absindex(state, -1);
- // lua_newuserdata and luaL_traceback may error
- void *error_ud = lua_newuserdata(state, MLUA_WRAPPED_ERROR_SIZE);
- int has_traceback = 0;
- if (lua_checkstack(state, LUA_TRACEBACK_STACK) != 0) {
- luaL_traceback(state, state, NULL, 0);
- has_traceback = 1;
- }
- wrapped_error_traceback(state, error_idx, error_ud, has_traceback);
+ // Convert to CallbackError
+ wrapped_error_traceback(state, -1, 0, 1);
return 1;
}
if (MLUA_WRAPPED_PANIC_KEY != NULL &&
- !is_wrapped_struct(state, -1, MLUA_WRAPPED_PANIC_KEY) &&
- lua_checkstack(state, LUA_TRACEBACK_STACK) != 0) {
+ !is_wrapped_struct(state, -1, MLUA_WRAPPED_PANIC_KEY)) {
const char *s = luaL_tolstring(state, -1, NULL);
- luaL_traceback(state, state, s, 0);
- lua_remove(state, -2);
+ if (lua_checkstack(state, LUA_TRACEBACK_STACK) != 0) {
+ luaL_traceback(state, state, s, 1);
+ lua_remove(state, -2);
+ }
}
return 1;
diff --git a/src/util.rs b/src/util.rs
index df41d2c..e5544f6 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,5 +1,6 @@
use std::any::{Any, TypeId};
use std::collections::HashMap;
+use std::error::Error as StdError;
use std::fmt::Write;
use std::os::raw::{c_int, c_void};
use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
@@ -312,7 +313,7 @@ where
Ok(Err(err)) => {
ffi::lua_settop(state, 1);
let error_ud = ffi::lua_touserdata(state, 1);
- ptr::write(error_ud as *mut WrappedError, WrappedError(err));
+ ptr::write(error_ud as *mut WrappedError, WrappedError(err, None));
get_gc_metatable_for::<WrappedError>(state);
ffi::lua_setmetatable(state, -2);
-1
@@ -323,45 +324,37 @@ where
ptr::write(error_ud as *mut WrappedPanic, WrappedPanic(Some(p)));
get_gc_metatable_for::<WrappedPanic>(state);
ffi::lua_setmetatable(state, -2);
- -1
+ -2
}
}
}
-// A part of the C shim (error_traceback).
-// Receives absolute index of error in the stack, a pointer to pre-allocated WrappedError memory,
-// and optional boolean flag if a traceback value is on top of the stack.
+// A part of the C shim for errors handling.
+// Receives indexes of error and traceback (optional) in the stack.
+// Depending on `convert_to_callback_error` flag attaches traceback to the error or
+// converts error into a `CallbackError` (using previously attached traceback).
#[no_mangle]
pub unsafe extern "C" fn wrapped_error_traceback(
state: *mut ffi::lua_State,
error_idx: c_int,
- error_ud: *mut c_void,
- has_traceback: c_int,
+ traceback_idx: c_int,
+ convert_to_callback_error: c_int,
) {
- let error = mlua_expect!(
- get_wrapped_error(state, error_idx).as_ref(),
+ let wrapped_error = mlua_expect!(
+ get_gc_userdata::<WrappedError>(state, error_idx).as_mut(),
"cannot get <WrappedError>"
);
- let traceback = if has_traceback != 0 {
- let traceback = to_string(state, -1);
- ffi::lua_pop(state, 1);
- traceback
- } else {
- "<not enough stack space for traceback>".to_owned()
- };
-
- let error = error.clone();
- ffi::lua_remove(state, -2); // Remove original error
- ptr::write(
- error_ud as *mut WrappedError,
- WrappedError(Error::CallbackError {
- traceback,
- cause: Arc::new(error),
- }),
- );
- get_gc_metatable_for::<WrappedError>(state);
- ffi::lua_setmetatable(state, -2);
+ if convert_to_callback_error != 0 {
+ let traceback = wrapped_error
+ .1
+ .take()
+ .unwrap_or_else(|| "<not enough stack space for traceback>".into());
+ let cause = Arc::new(wrapped_error.0.clone());
+ wrapped_error.0 = Error::CallbackError { traceback, cause };
+ } else {
+ wrapped_error.1 = Some(to_string(state, traceback_idx));
+ }
}
// Returns Lua main thread for Lua >= 5.2 or checks that the passed thread is main for Lua 5.1.
@@ -391,7 +384,7 @@ pub unsafe fn get_main_state(state: *mut ffi::lua_State) -> Option<*mut ffi::lua
// Uses 2 stack spaces and does not call checkstack.
pub unsafe fn push_wrapped_error(state: *mut ffi::lua_State, err: Error) -> Result<()> {
let error_ud = ffi::safe::lua_newwrappederror(state)? as *mut WrappedError;
- ptr::write(error_ud, WrappedError(err));
+ ptr::write(error_ud, WrappedError(err, None));
get_gc_metatable_for::<WrappedError>(state);
ffi::lua_setmetatable(state, -2);
Ok(())
@@ -464,7 +457,8 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(*const
callback_error(state, |_| {
check_stack(state, 3)?;
- let err_buf = if let Some(error) = get_wrapped_error(state, -1).as_ref() {
+ let wrapped_error = get_gc_userdata::<WrappedError>(state, -1).as_ref();
+ let err_buf = if let Some(error) = wrapped_error {
let err_buf_key = &ERROR_PRINT_BUFFER_KEY as *const u8 as *const c_void;
ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, err_buf_key);
let err_buf = ffi::lua_touserdata(state, -1) as *mut String;
@@ -474,7 +468,41 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(*const
// Depending on how the API is used and what error types scripts are given, it may
// be possible to make this consume arbitrary amounts of memory (for example, some
// kind of recursive error structure?)
- let _ = write!(&mut (*err_buf), "{}", error);
+ let _ = write!(&mut (*err_buf), "{}", error.0);
+ match error {
+ WrappedError(Error::CallbackError { .. }, _) => {}
+ // This is a workaround to avoid having duplicate traceback for string errors
+ // with attached traceback at the `error_traceback` (message handler) stage.
+ WrappedError(Error::RuntimeError(ref err), _)
+ if err.contains("\nstack traceback:\n") => {}
+ WrappedError(_, Some(ref traceback)) => {
+ let _ = write!(&mut (*err_buf), "\n{}", traceback);
+ }
+ _ => {}
+ }
+ // Find first two sources that caused the error
+ let mut source1 = error.0.source();
+ let mut source0 = source1.and_then(|s| s.source());
+ while let Some(source) = source0.and_then(|s| s.source()) {
+ source1 = source0;
+ source0 = Some(source);
+ }
+ match (source1, source0) {
+ (_, Some(error0)) if error0.to_string().contains("\nstack traceback:\n") => {
+ let _ = write!(&mut (*err_buf), "\ncaused by: {}", error0);
+ }
+ (Some(error1), Some(error0)) => {
+ let _ = write!(&mut (*err_buf), "\ncaused by: {}", error0);
+ let s = error1.to_string();
+ if let Some(traceback) = s.splitn(2, "\nstack traceback:\n").nth(1) {
+ let _ = write!(&mut (*err_buf), "\nstack traceback:\n{}", traceback);
+ }
+ }
+ (Some(error1), None) => {
+ let _ = write!(&mut (*err_buf), "\ncaused by: {}", error1);
+ }
+ _ => {}
+ }
Ok(err_buf)
} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_ref() {
if let Some(ref p) = (*panic).0 {
@@ -529,7 +557,7 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(*const
callback_error(state, |_| {
check_stack(state, 2)?;
let error_ud = ffi::safe::lua_newwrappederror(state)? as *mut WrappedError;
- ptr::write(error_ud, WrappedError(Error::CallbackDestructed));
+ ptr::write(error_ud, WrappedError(Error::CallbackDestructed, None));
get_gc_metatable_for::<WrappedError>(state);
ffi::lua_setmetatable(state, -2);
Ok(-1) // to trigger lua_error
@@ -593,7 +621,7 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(*const
Ok((wrapped_error_key, wrapped_panic_key))
}
-pub(crate) struct WrappedError(pub Error);
+pub(crate) struct WrappedError(pub Error, pub Option<String>);
pub(crate) struct WrappedPanic(pub Option<Box<dyn Any + Send + 'static>>);
// Converts the given lua value to a string in a reasonable format without causing a Lua error or