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The following commit(s) were added to refs/heads/main by this push:
new 794a844642 fix: take FFI_ArrowArrayStream errno values from libc
(#10299)
794a844642 is described below
commit 794a844642ef37d64ce164d2da581734158ed233
Author: Fredrik Fornwall <[email protected]>
AuthorDate: Thu Jul 16 01:45:58 2026 +0200
fix: take FFI_ArrowArrayStream errno values from libc (#10299)
**Disclaimer**: The PR description and the code change was generated by
claude code. I have reviewed it and think it makes sense, and is ready
to dig into any eventual issues or make necessary modifications.
The `errno` constants in `ffi_stream.rs` were hardcoded to a single set
of values, but `ENOSYS` is `78` only on macOS/iOS and the BSDs — on
Linux it is `38`, on Windows `40`, on Solaris/illumos `89`. On WASI even
the other codes differ (`EINVAL` is `28`, `EIO` `29`, `ENOMEM` `48`),
since WASI numbers its errnos independently. A stream exported on Linux
therefore reported `ArrowError::NotYetImplemented` as `78`, which Linux
errno tables read as an unrelated code, confusing C consumers that
interpret the returned errno.
Take the constants from libc instead, as an optional dependency of the
ffi feature. It is target-gated off `wasm32-unknown-unknown` — the one
target without a libc — where no OS interprets the codes anyway, so
hardcoded Linux values remain.
Signed-off-by: Fredrik Fornwall <[email protected]>
---
Cargo.lock | 1 +
arrow-array/Cargo.toml | 7 ++++++-
arrow-array/src/ffi_stream.rs | 13 ++++++++++++-
3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/Cargo.lock b/Cargo.lock
index 3873215342..d33ed9b78e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -222,6 +222,7 @@ dependencies = [
"futures",
"half",
"hashbrown 0.17.1",
+ "libc",
"num-complex",
"num-integer",
"num-traits",
diff --git a/arrow-array/Cargo.toml b/arrow-array/Cargo.toml
index df102c32b0..4ec358fe85 100644
--- a/arrow-array/Cargo.toml
+++ b/arrow-array/Cargo.toml
@@ -45,6 +45,11 @@ ahash = { version = "0.8", default-features = false,
features = ["compile-time-r
[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
ahash = { version = "0.8", default-features = false, features =
["runtime-rng"] }
+# Used by the ffi feature for platform-correct errno values. Excluded on
+# wasm32-unknown-unknown, which has no libc.
+[target.'cfg(not(all(target_family = "wasm", target_os =
"unknown")))'.dependencies]
+libc = { version = "0.2", default-features = false, optional = true }
+
[dependencies]
arrow-buffer = { workspace = true }
arrow-schema = { workspace = true }
@@ -63,7 +68,7 @@ all-features = true
[features]
async = ["dep:futures"]
-ffi = ["arrow-schema/ffi", "arrow-data/ffi"]
+ffi = ["arrow-schema/ffi", "arrow-data/ffi", "dep:libc"]
force_validate = []
# Enable memory tracking support
pool = ["arrow-buffer/pool", "arrow-data/pool"]
diff --git a/arrow-array/src/ffi_stream.rs b/arrow-array/src/ffi_stream.rs
index 815d7c5760..9a09c3753d 100644
--- a/arrow-array/src/ffi_stream.rs
+++ b/arrow-array/src/ffi_stream.rs
@@ -74,10 +74,21 @@ use crate::record_batch::{RecordBatch, RecordBatchReader};
type Result<T> = std::result::Result<T, ArrowError>;
+// Errno values returned through the C stream interface, taken from libc so
they match
+// the platform the consumer interprets them against.
+#[cfg(not(all(target_family = "wasm", target_os = "unknown")))]
+use libc::{EINVAL, EIO, ENOMEM, ENOSYS};
+
+// wasm32-unknown-unknown has no libc, and no OS to interpret the codes either
— any
+// non-zero value works there, so use Linux's.
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
const ENOMEM: i32 = 12;
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
const EIO: i32 = 5;
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
const EINVAL: i32 = 22;
-const ENOSYS: i32 = 78;
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
+const ENOSYS: i32 = 38;
/// ABI-compatible struct for `ArrayStream` from C Stream Interface
/// See
<https://arrow.apache.org/docs/format/CStreamInterface.html#structure-definitions>
