Skip to content

GH-49995: [R][Wasm] Fix threading issue under Wasm/Emscripten #49996

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
amoeba wants to merge 10 commits into
base: main
Choose a base branch
from
Open

GH-49995: [R][Wasm] Fix threading issue under Wasm/Emscripten #49996

Show file tree
Hide file tree
Changes from 3 commits
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
dadf0f5
Try to fix issue
amoeba May 19, 2026
abaacb8
test not setting usethreads
amoeba May 19, 2026
bafaf05
set back
amoeba May 20, 2026
19efaf3
wip, run tests under wasm
amoeba May 20, 2026
47738fa
set NODE_PATH
amoeba May 20, 2026
9f03a2a
try this for tests
amoeba May 21, 2026
dd555bc
tidy up a bit
amoeba May 21, 2026
80a2fb1
configure tzdb
amoeba May 21, 2026
dee814c
add skip
amoeba May 21, 2026
b8810d9
add debug info for ci
amoeba May 21, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions r/R/arrow-package.R
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,11 @@ s3_finalizer <- new.env(parent = emptyenv())
# needs the C++ library loaded
create_binding_cache()

if (identical(R.version$os, "emscripten")) {
# Disable multithreading on Wasm/Emscripten
options(arrow.use_threads = FALSE)
}

if (tolower(Sys.info()[["sysname"]]) == "windows") {
# Disable multithreading on Windows
# See https://issues.apache.org/jira/browse/ARROW-8379
Expand Down
11 changes: 10 additions & 1 deletion r/src/safe-call-into-r-impl.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,16 @@ bool SetEnableSignalStopSource(bool enabled) {
}

// [[arrow::export]]
bool CanRunWithCapturedR() { return MainRThread::GetInstance().Executor() == nullptr; }
bool CanRunWithCapturedR() {
#ifdef __EMSCRIPTEN__
// Threading is not supported under Emscripten/WASM. Always take the
// synchronous path to avoid attempting pthread_create which will fail
// with "thread constructor failed: Not supported".
return false;
#else
return MainRThread::GetInstance().Executor() == nullptr;
#endif
Comment on lines +48 to +56
Copy link
Copy Markdown
Member

@jonkeane jonkeane May 20, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is it possible to add a test (or maybe it's that we actually need to run the tests under wasm(???) to catch this?

Copy link
Copy Markdown
Member Author

@amoeba amoeba May 20, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It looks like maybe we can at least run some R code in the container if not run the test suite. I'll report back.

}

// [[arrow::export]]
std::string TestSafeCallIntoR(cpp11::function r_fun_that_returns_a_string,
Expand Down
Loading