Auto merge of rust-lang#128319 - tgross35:rollup-ko07weh, r=tgross35

Rollup of 4 pull requests

Successful merges:

 - rust-lang#109174 (Replace `io::Cursor::{remaining_slice, is_empty}`)
 - rust-lang#128147 (migrate fmt-write-bloat to rmake)
 - rust-lang#128182 (handle no_std targets on std builds)
 - rust-lang#128310 (Add missing periods on `BTreeMap` cursor `peek_next` docs)

Failed merges:

 - rust-lang#128269 (improve cargo invocations on bootstrap)

r? `@ghost`
`@rustbot` modify labels: rollup

library/alloc/src/collections/btree/map.rs

@@ -2921,7 +2921,7 @@ impl<'a, K, V> Cursor<'a, K, V> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&self) -> Option<(&'a K, &'a V)> {
         self.clone().next()
@@ -2963,7 +2963,7 @@ impl<'a, K, V, A> CursorMut<'a, K, V, A> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&mut self) -> Option<(&K, &mut V)> {
         let (k, v) = self.inner.peek_next()?;
@@ -3061,7 +3061,7 @@ impl<'a, K, V, A> CursorMutKey<'a, K, V, A> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&mut self) -> Option<(&mut K, &mut V)> {
         let current = self.current.as_mut()?;

library/std/src/io/cursor.rs

@@ -210,55 +210,60 @@ impl<T> Cursor<T>
 where
     T: AsRef<[u8]>,
 {
-    /// Returns the remaining slice.
+    /// Splits the underlying slice at the cursor position and returns them.
     ///
     /// # Examples
     ///
     /// ```
-    /// #![feature(cursor_remaining)]
+    /// #![feature(cursor_split)]
     /// use std::io::Cursor;
     ///
     /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
     ///
-    /// assert_eq!(buff.remaining_slice(), &[1, 2, 3, 4, 5]);
+    /// assert_eq!(buff.split(), ([].as_slice(), [1, 2, 3, 4, 5].as_slice()));
     ///
     /// buff.set_position(2);
-    /// assert_eq!(buff.remaining_slice(), &[3, 4, 5]);
-    ///
-    /// buff.set_position(4);
-    /// assert_eq!(buff.remaining_slice(), &[5]);
+    /// assert_eq!(buff.split(), ([1, 2].as_slice(), [3, 4, 5].as_slice()));
     ///
     /// buff.set_position(6);
-    /// assert_eq!(buff.remaining_slice(), &[]);
+    /// assert_eq!(buff.split(), ([1, 2, 3, 4, 5].as_slice(), [].as_slice()));
     /// ```
-    #[unstable(feature = "cursor_remaining", issue = "86369")]
-    pub fn remaining_slice(&self) -> &[u8] {
-        let len = self.pos.min(self.inner.as_ref().len() as u64);
-        &self.inner.as_ref()[(len as usize)..]
+    #[unstable(feature = "cursor_split", issue = "86369")]
+    pub fn split(&self) -> (&[u8], &[u8]) {
+        let slice = self.inner.as_ref();
+        let pos = self.pos.min(slice.len() as u64);
+        slice.split_at(pos as usize)
     }
+}
 
-    /// Returns `true` if the remaining slice is empty.
+impl<T> Cursor<T>
+where
+    T: AsMut<[u8]>,
+{
+    /// Splits the underlying slice at the cursor position and returns them
+    /// mutably.
     ///
     /// # Examples
     ///
     /// ```
-    /// #![feature(cursor_remaining)]
+    /// #![feature(cursor_split)]
     /// use std::io::Cursor;
     ///
     /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
     ///
-    /// buff.set_position(2);
-    /// assert!(!buff.is_empty());
+    /// assert_eq!(buff.split_mut(), ([].as_mut_slice(), [1, 2, 3, 4, 5].as_mut_slice()));
     ///
-    /// buff.set_position(5);
-    /// assert!(buff.is_empty());
+    /// buff.set_position(2);
+    /// assert_eq!(buff.split_mut(), ([1, 2].as_mut_slice(), [3, 4, 5].as_mut_slice()));
     ///
-    /// buff.set_position(10);
-    /// assert!(buff.is_empty());
+    /// buff.set_position(6);
+    /// assert_eq!(buff.split_mut(), ([1, 2, 3, 4, 5].as_mut_slice(), [].as_mut_slice()));
     /// ```
-    #[unstable(feature = "cursor_remaining", issue = "86369")]
-    pub fn is_empty(&self) -> bool {
-        self.pos >= self.inner.as_ref().len() as u64
+    #[unstable(feature = "cursor_split", issue = "86369")]
+    pub fn split_mut(&mut self) -> (&mut [u8], &mut [u8]) {
+        let slice = self.inner.as_mut();
+        let pos = self.pos.min(slice.len() as u64);
+        slice.split_at_mut(pos as usize)
     }
 }
 
@@ -320,15 +325,15 @@ where
     T: AsRef<[u8]>,
 {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let n = Read::read(&mut self.remaining_slice(), buf)?;
+        let n = Read::read(&mut Cursor::split(self).1, buf)?;
         self.pos += n as u64;
         Ok(n)
     }
 
     fn read_buf(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
         let prev_written = cursor.written();
 
-        Read::read_buf(&mut self.remaining_slice(), cursor.reborrow())?;
+        Read::read_buf(&mut Cursor::split(self).1, cursor.reborrow())?;
 
         self.pos += (cursor.written() - prev_written) as u64;
 
@@ -352,7 +357,7 @@ where
     }
 
     fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
-        let result = Read::read_exact(&mut self.remaining_slice(), buf);
+        let result = Read::read_exact(&mut Cursor::split(self).1, buf);
 
         match result {
             Ok(_) => self.pos += buf.len() as u64,
@@ -366,14 +371,14 @@ where
     fn read_buf_exact(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
         let prev_written = cursor.written();
 
-        let result = Read::read_buf_exact(&mut self.remaining_slice(), cursor.reborrow());
+        let result = Read::read_buf_exact(&mut Cursor::split(self).1, cursor.reborrow());
         self.pos += (cursor.written() - prev_written) as u64;
 
         result
     }
 
     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
-        let content = self.remaining_slice();
+        let content = Cursor::split(self).1;
         let len = content.len();
         buf.try_reserve(len)?;
         buf.extend_from_slice(content);
@@ -384,7 +389,7 @@ where
 
     fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
         let content =
-            crate::str::from_utf8(self.remaining_slice()).map_err(|_| io::Error::INVALID_UTF8)?;
+            crate::str::from_utf8(Cursor::split(self).1).map_err(|_| io::Error::INVALID_UTF8)?;
         let len = content.len();
         buf.try_reserve(len)?;
         buf.push_str(content);
@@ -400,7 +405,7 @@ where
     T: AsRef<[u8]>,
 {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        Ok(self.remaining_slice())
+        Ok(Cursor::split(self).1)
     }
     fn consume(&mut self, amt: usize) {
         self.pos += amt as u64;

library/std/src/io/tests.rs

@@ -675,13 +675,13 @@ fn cursor_read_exact_eof() {
 
     let mut r = slice.clone();
     assert!(r.read_exact(&mut [0; 10]).is_err());
-    assert!(r.is_empty());
+    assert!(Cursor::split(&r).1.is_empty());
 
     let mut r = slice;
     let buf = &mut [0; 10];
     let mut buf = BorrowedBuf::from(buf.as_mut_slice());
     assert!(r.read_buf_exact(buf.unfilled()).is_err());
-    assert!(r.is_empty());
+    assert!(Cursor::split(&r).1.is_empty());
     assert_eq!(buf.filled(), b"123456");
 }
 

src/bootstrap/src/core/build_steps/check.rs

@@ -1,7 +1,7 @@
 //! Implementation of compiling the compiler and standard library, in "check"-based modes.
 
 use crate::core::build_steps::compile::{
-    add_to_sysroot, run_cargo, rustc_cargo, rustc_cargo_env, std_cargo,
+    add_to_sysroot, run_cargo, rustc_cargo, rustc_cargo_env, std_cargo, std_crates_for_run_make,
 };
 use crate::core::build_steps::tool::{prepare_tool_cargo, SourceType};
 use crate::core::builder::{
@@ -47,7 +47,7 @@ impl Step for Std {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        let crates = run.make_run_crates(Alias::Library);
+        let crates = std_crates_for_run_make(&run);
         run.builder.ensure(Std { target: run.target, crates });
     }
 

src/bootstrap/src/core/build_steps/clippy.rs

@@ -19,6 +19,7 @@ use super::compile::libstd_stamp;
 use super::compile::run_cargo;
 use super::compile::rustc_cargo;
 use super::compile::std_cargo;
+use super::compile::std_crates_for_run_make;
 use super::tool::prepare_tool_cargo;
 use super::tool::SourceType;
 
@@ -120,7 +121,7 @@ impl Step for Std {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        let crates = run.make_run_crates(Alias::Library);
+        let crates = std_crates_for_run_make(&run);
         run.builder.ensure(Std { target: run.target, crates });
     }
 

src/bootstrap/src/core/build_steps/compile.rs

@@ -127,11 +127,7 @@ impl Step for Std {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        // If the paths include "library", build the entire standard library.
-        let has_alias =
-            run.paths.iter().any(|set| set.assert_single_path().path.ends_with("library"));
-        let crates = if has_alias { Default::default() } else { run.cargo_crates_in_set() };
-
+        let crates = std_crates_for_run_make(&run);
         run.builder.ensure(Std {
             compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
             target: run.target,
@@ -429,6 +425,28 @@ fn copy_self_contained_objects(
     target_deps
 }
 
+/// Resolves standard library crates for `Std::run_make` for any build kind (like check, build, clippy, etc.).
+pub fn std_crates_for_run_make(run: &RunConfig<'_>) -> Vec<String> {
+    // FIXME: Extend builder tests to cover the `crates` field of `Std` instances.
+    if cfg!(feature = "bootstrap-self-test") {
+        return vec![];
+    }
+
+    let has_alias = run.paths.iter().any(|set| set.assert_single_path().path.ends_with("library"));
+    let target_is_no_std = run.builder.no_std(run.target).unwrap_or(false);
+
+    // For no_std targets, do not add any additional crates to the compilation other than what `compile::std_cargo` already adds for no_std targets.
+    if target_is_no_std {
+        vec![]
+    }
+    // If the paths include "library", build the entire standard library.
+    else if has_alias {
+        run.make_run_crates(builder::Alias::Library)
+    } else {
+        run.cargo_crates_in_set()
+    }
+}
+
 /// Configure cargo to compile the standard library, adding appropriate env vars
 /// and such.
 pub fn std_cargo(builder: &Builder<'_>, target: TargetSelection, stage: u32, cargo: &mut Cargo) {

src/bootstrap/src/core/build_steps/dist.rs

@@ -108,7 +108,6 @@ impl Step for JsonDocs {
         builder.ensure(crate::core::build_steps::doc::Std::new(
             builder.top_stage,
             host,
-            builder,
             DocumentationFormat::Json,
         ));
 

src/bootstrap/src/core/build_steps/doc.rs

@@ -563,18 +563,8 @@ pub struct Std {
 }
 
 impl Std {
-    pub(crate) fn new(
-        stage: u32,
-        target: TargetSelection,
-        builder: &Builder<'_>,
-        format: DocumentationFormat,
-    ) -> Self {
-        let crates = builder
-            .in_tree_crates("sysroot", Some(target))
-            .into_iter()
-            .map(|krate| krate.name.to_string())
-            .collect();
-        Std { stage, target, format, crates }
+    pub(crate) fn new(stage: u32, target: TargetSelection, format: DocumentationFormat) -> Self {
+        Std { stage, target, format, crates: vec![] }
     }
 }
 
@@ -588,6 +578,7 @@ impl Step for Std {
     }
 
     fn make_run(run: RunConfig<'_>) {
+        let crates = compile::std_crates_for_run_make(&run);
         run.builder.ensure(Std {
             stage: run.builder.top_stage,
             target: run.target,
@@ -596,7 +587,7 @@ impl Step for Std {
             } else {
                 DocumentationFormat::Html
             },
-            crates: run.make_run_crates(Alias::Library),
+            crates,
         });
     }
 
@@ -694,13 +685,6 @@ fn doc_std(
     extra_args: &[&str],
     requested_crates: &[String],
 ) {
-    if builder.no_std(target) == Some(true) {
-        panic!(
-            "building std documentation for no_std target {target} is not supported\n\
-             Set `docs = false` in the config to disable documentation, or pass `--skip library`."
-        );
-    }
-
     let compiler = builder.compiler(stage, builder.config.build);
 
     let target_doc_dir_name = if format == DocumentationFormat::Json { "json-doc" } else { "doc" };

src/bootstrap/src/core/build_steps/test.rs

@@ -852,7 +852,6 @@ impl Step for RustdocJSStd {
         builder.ensure(crate::core::build_steps::doc::Std::new(
             builder.top_stage,
             self.target,
-            builder,
             DocumentationFormat::Html,
         ));
         let _guard = builder.msg(

src/bootstrap/src/core/builder/tests.rs

@@ -78,13 +78,9 @@ macro_rules! std {
 
 macro_rules! doc_std {
     ($host:ident => $target:ident, stage = $stage:literal) => {{
-        let config = configure("doc", &["A-A"], &["A-A"]);
-        let build = Build::new(config);
-        let builder = Builder::new(&build);
         doc::Std::new(
             $stage,
             TargetSelection::from_user(concat!(stringify!($target), "-", stringify!($target))),
-            &builder,
             DocumentationFormat::Html,
         )
     }};

src/tools/run-make-support/src/env.rs

@@ -17,3 +17,10 @@ pub fn env_var_os(name: &str) -> OsString {
         None => panic!("failed to retrieve environment variable {name:?}"),
     }
 }
+
+/// Check if `NO_DEBUG_ASSERTIONS` is set (usually this may be set in CI jobs).
+#[track_caller]
+#[must_use]
+pub fn no_debug_assertions() -> bool {
+    std::env::var_os("NO_DEBUG_ASSERTIONS").is_some()
+}

src/tools/run-make-support/src/lib.rs

@@ -21,6 +21,7 @@ pub mod run;
 pub mod scoped_run;
 pub mod string;
 pub mod targets;
+pub mod symbols;
 
 // Internally we call our fs-related support module as `fs`, but re-export its content as `rfs`
 // to tests to avoid colliding with commonly used `use std::fs;`.