assert that write_at doesn't change the seek position

Author: the8472

.github/workflows/ci.yml

@@ -146,6 +146,11 @@ jobs:
       - name: ensure the channel matches the target branch
         run: src/ci/scripts/verify-channel.sh
 
+      - name: print kernel/libc versions
+        if: runner.os == 'Linux'
+        run: |
+          uname -a
+
       - name: collect CPU statistics
         run: src/ci/scripts/collect-cpu-stats.sh
 

library/std/src/fs/tests.rs

@@ -34,6 +34,7 @@ use crate::sync::Arc;
 use crate::test_helpers::{TempDir, tmpdir};
 use crate::time::{Duration, Instant, SystemTime};
 use crate::{env, str, thread};
+use crate::bstr::ByteStr;
 
 macro_rules! check {
     ($e:expr) => {
@@ -500,11 +501,13 @@ fn file_test_append_write_at() {
     let msg = b"it's not working!";
     check!(fs::write(&filename, &msg));
     // write_at should work even in in append mode
-    let f = check!(fs::File::options().append(true).open(&filename));
+    let mut f = check!(fs::File::options().append(true).open(&filename));
+    assert_eq!(check!(f.stream_position()), 0);
     assert_eq!(check!(f.write_at(b"   ", 5)), 3);
+    assert_eq!(check!(f.stream_position()), 0);
 
     let content = check!(fs::read(&filename));
-    assert_eq!(&content, b"it's     working!");
+    assert_eq!(ByteStr::new(&content), ByteStr::new(b"it's     working!"));
 }
 
 #[test]

library/std/src/os/unix/fs/tests.rs

@@ -1,4 +1,6 @@
 use super::*;
+use crate::io::Seek;
+use crate::bstr::ByteStr;
 
 #[test]
 fn read_vectored_at() {
@@ -40,21 +42,23 @@ fn write_vectored_at() {
     }
     let expected = {
         // Open in append mode to test that positioned writes bypass O_APPEND.
-        let file = fs::File::options().append(true).open(&filename).unwrap();
+        let mut file = fs::File::options().append(true).open(&filename).unwrap();
         let buf0 = b"    ";
         let buf1 = b"great  ";
 
         let iovec = [io::IoSlice::new(buf0), io::IoSlice::new(buf1)];
 
+        assert_eq!(file.stream_position().unwrap(), 0);
         let n = file.write_vectored_at(&iovec, 11).unwrap();
+        assert_eq!(file.stream_position().unwrap(), 0);
 
         assert!(n == 4 || n == 11);
 
         if n == 4 { b"pwritev is     working!" } else { b"pwritev is     great  !" }
     };
 
     let content = fs::read(&filename).unwrap();
-    assert_eq!(&content, expected);
+    assert_eq!(ByteStr::new(&content), ByteStr::new(expected));
 }
 
 #[test]

library/std/src/sys/fd/unix.rs

@@ -680,6 +680,7 @@ impl FileDesc {
                     if let Some(err) = e.raw_os_error()
                         && (err == libc::EOPNOTSUPP || err == libc::ENOSYS) =>
                 {
+                    eprintln!("pwritev2 NOAPPEND error: {err}");
                     NOAPPEND_SUPPORTED.store(false, core::sync::atomic::Ordering::Relaxed);
                     return None;
                 }

src/ci/docker/host-x86_64/pr-check-2/Dockerfile

@@ -27,16 +27,5 @@ COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV SCRIPT \
-        python3 ../x.py check && \
-        python3 ../x.py clippy ci && \
-        python3 ../x.py test --stage 1 core alloc std test proc_macro && \
-        python3 ../x.py doc --stage 0 bootstrap && \
-        # Build both public and internal documentation.
-        RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 0 compiler && \
-        RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 1 library && \
-        mkdir -p /checkout/obj/staging/doc && \
-        cp -r build/x86_64-unknown-linux-gnu/doc /checkout/obj/staging && \
-        RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 1 library/test && \
-        # The BOOTSTRAP_TRACING flag is added to verify whether the 
-        # bootstrap process compiles successfully with this flag enabled.
-        BOOTSTRAP_TRACING=1 python3 ../x.py --help
+        ldd --version && \
+        python3 ../x.py test --stage 1 std -- "write"