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Devtools: send error replies instead of ignoring messages (#37686)

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Client messages, which are always requests, are dispatched to Actor
instances one at a time via Actor::handle_message. Each request must be
paired with exactly one reply from the same actor the request was sent
to, where a reply is a message with no type (if a message from the
server has a type, it’s a notification, not a reply).

Failing to reply to a request will almost always permanently break that
actor, because either the client gets stuck waiting for a reply, or the
client receives the reply for a subsequent request as if it was the
reply for the current request. If an actor fails to reply to a request,
we want the dispatcher (ActorRegistry::handle_message) to send an error
of type `unrecognizedPacketType`, to keep the conversation for that
actor in sync. Since replies come in all shapes and sizes, we want to
allow Actor types to send replies without having to return them to the
dispatcher.

This patch adds a wrapper type around a client stream that guarantees
request/reply invariants. It allows the dispatcher to check if a valid
reply was sent, and guarantees that if the actor tries to send a reply,
it’s actually a valid reply (see ClientRequest::is_valid_reply). It does
not currently guarantee anything about messages sent via the TcpStream
released via ClientRequest::try_clone_stream or the return value of
ClientRequest::reply. We also send `unrecognizedPacketType`,
`missingParameter`, `badParameterType`, and `noSuchActor` messages per
the
[protocol](https://firefox-source-docs.mozilla.org/devtools/backend/protocol.html#error-packets)
[docs](https://firefox-source-docs.mozilla.org/devtools/backend/protocol.html#packets).

Testing: automated tests all pass, and manual testing looks ok
Fixes: #37683 and at least six bugs, plus one with a different root
cause, plus three with zero impact

---------

Signed-off-by: atbrakhi <atbrakhi@igalia.com>
Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: delan azabani <dazabani@igalia.com>
Co-authored-by: Simon Wülker <simon.wuelker@arcor.de>
Co-authored-by: the6p4c <me@doggirl.gay>
This commit is contained in:
atbrakhi 2025-07-07 14:40:44 +02:00 • committed by GitHub
parent fcb2a4cd95
commit 71d97bd935
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
36 changed files with 661 additions and 637 deletions
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92
components/devtools/actors/inspector/walker.rs
View file

@ -5,7 +5,6 @@
//! The walker actor is responsible for traversing the DOM tree in various ways to create new nodes
use std::cell::RefCell;
use std::net::TcpStream;
use base::id::PipelineId;
use devtools_traits::DevtoolScriptControlMsg::{GetChildren, GetDocumentElement};
@ -14,10 +13,10 @@ use ipc_channel::ipc::{self, IpcSender};
use serde::Serialize;
use serde_json::{self, Map, Value};
use crate::actor::{Actor, ActorMessageStatus, ActorRegistry};
use crate::actor::{Actor, ActorError, ActorRegistry};
use crate::actors::inspector::layout::{LayoutInspectorActor, LayoutInspectorActorMsg};
use crate::actors::inspector::node::{NodeActorMsg, NodeInfoToProtocol};
use crate::protocol::JsonPacketStream;
use crate::protocol::{ClientRequest, JsonPacketStream};
use crate::{EmptyReplyMsg, StreamId};
#[derive(Serialize)]
@ -64,7 +63,7 @@ struct GetLayoutInspectorReply {
}
#[derive(Serialize)]
struct WatchRootNodeReply {
struct WatchRootNodeNotification {
#[serde(rename = "type")]
type_: String,
from: String,
@ -94,7 +93,7 @@ struct GetOffsetParentReply {
}
#[derive(Serialize)]
struct NewMutationsReply {
struct NewMutationsNotification {
from: String,
#[serde(rename = "type")]
type_: String,
@ -123,24 +122,31 @@ impl Actor for WalkerActor {
/// node and its ascendents
fn handle_message(
&self,
mut request: ClientRequest,
registry: &ActorRegistry,
msg_type: &str,
msg: &Map<String, Value>,
stream: &mut TcpStream,
_id: StreamId,
) -> Result<ActorMessageStatus, ()> {
Ok(match msg_type {
) -> Result<(), ActorError> {
match msg_type {
"children" => {
let target = msg.get("node").ok_or(())?.as_str().ok_or(())?;
let (tx, rx) = ipc::channel().map_err(|_| ())?;
let target = msg
.get("node")
.ok_or(ActorError::MissingParameter)?
.as_str()
.ok_or(ActorError::BadParameterType)?;
let (tx, rx) = ipc::channel().map_err(|_| ActorError::Internal)?;
self.script_chan
.send(GetChildren(
self.pipeline,
registry.actor_to_script(target.into()),
tx,
))
.map_err(|_| ())?;
let children = rx.recv().map_err(|_| ())?.ok_or(())?;
.map_err(|_| ActorError::Internal)?;
let children = rx
.recv()
.map_err(|_| ActorError::Internal)?
.ok_or(ActorError::Internal)?;
let msg = ChildrenReply {
has_first: true,
@ -159,20 +165,21 @@ impl Actor for WalkerActor {
.collect(),
from: self.name(),
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"clearPseudoClassLocks" => {
let msg = EmptyReplyMsg { from: self.name() };
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"documentElement" => {
let (tx, rx) = ipc::channel().map_err(|_| ())?;
let (tx, rx) = ipc::channel().map_err(|_| ActorError::Internal)?;
self.script_chan
.send(GetDocumentElement(self.pipeline, tx))
.map_err(|_| ())?;
let doc_elem_info = rx.recv().map_err(|_| ())?.ok_or(())?;
.map_err(|_| ActorError::Internal)?;
let doc_elem_info = rx
.recv()
.map_err(|_| ActorError::Internal)?
.ok_or(ActorError::Internal)?;
let node = doc_elem_info.encode(
registry,
true,
@ -185,8 +192,7 @@ impl Actor for WalkerActor {
from: self.name(),
node,
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"getLayoutInspector" => {
// TODO: Create actual layout inspector actor
@ -198,8 +204,7 @@ impl Actor for WalkerActor {
from: self.name(),
actor,
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"getMutations" => {
let msg = GetMutationsReply {
@ -216,20 +221,26 @@ impl Actor for WalkerActor {
})
.collect(),
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"getOffsetParent" => {
let msg = GetOffsetParentReply {
from: self.name(),
node: None,
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"querySelector" => {
let selector = msg.get("selector").ok_or(())?.as_str().ok_or(())?;
let node = msg.get("node").ok_or(())?.as_str().ok_or(())?;
let selector = msg
.get("selector")
.ok_or(ActorError::MissingParameter)?
.as_str()
.ok_or(ActorError::BadParameterType)?;
let node = msg
.get("node")
.ok_or(ActorError::MissingParameter)?
.as_str()
.ok_or(ActorError::BadParameterType)?;
let mut hierarchy = find_child(
&self.script_chan,
self.pipeline,
@ -239,39 +250,38 @@ impl Actor for WalkerActor {
vec![],
|msg| msg.display_name == selector,
)
.map_err(|_| ())?;
.map_err(|_| ActorError::Internal)?;
hierarchy.reverse();
let node = hierarchy.pop().ok_or(())?;
let node = hierarchy.pop().ok_or(ActorError::Internal)?;
let msg = QuerySelectorReply {
from: self.name(),
node,
new_parents: hierarchy,
};
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
"watchRootNode" => {
let msg = WatchRootNodeReply {
let msg = WatchRootNodeNotification {
type_: "root-available".into(),
from: self.name(),
node: self.root_node.clone(),
};
let _ = stream.write_json_packet(&msg);
let _ = request.write_json_packet(&msg);
let msg = EmptyReplyMsg { from: self.name() };
let _ = stream.write_json_packet(&msg);
ActorMessageStatus::Processed
request.reply_final(&msg)?
},
_ => ActorMessageStatus::Ignored,
})
_ => return Err(ActorError::UnrecognizedPacketType),
};
Ok(())
}
}
impl WalkerActor {
pub(crate) fn new_mutations(
&self,
stream: &mut TcpStream,
request: &mut ClientRequest,
target: &str,
modifications: &[AttrModification],
) {
@ -279,7 +289,7 @@ impl WalkerActor {
let mut mutations = self.mutations.borrow_mut();
mutations.extend(modifications.iter().cloned().map(|m| (m, target.into())));
}
let _ = stream.write_json_packet(&NewMutationsReply {
let _ = request.write_json_packet(&NewMutationsNotification {
from: self.name(),
type_: "newMutations".into(),
});