Rollup merge of #138678 - durin42:rmeta-stability, r=fmease

rustc_resolve: fix instability in lib.rmeta contents

rust-lang/rust@23032f31c9 accidentally introduced some nondeterminism in the ordering of lib.rmeta files, which we caught in our bazel-based builds only recently due to being further behind than normal. In my testing, this fixes the issue.

Cargo.lock

@@ -4300,6 +4300,7 @@ name = "rustc_resolve"
 version = "0.0.0"
 dependencies = [
  "bitflags",
+ "itertools",
  "pulldown-cmark 0.11.3",
  "rustc_arena",
  "rustc_ast",

compiler/rustc_resolve/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 # tidy-alphabetical-start
 bitflags = "2.4.1"
+itertools = "0.12"
 pulldown-cmark = { version = "0.11", features = ["html"], default-features = false }
 rustc_arena = { path = "../rustc_arena" }
 rustc_ast = { path = "../rustc_ast" }

compiler/rustc_resolve/src/rustdoc.rs

@@ -1,13 +1,15 @@
 use std::mem;
 use std::ops::Range;
 
+use itertools::Itertools;
 use pulldown_cmark::{
     BrokenLink, BrokenLinkCallback, CowStr, Event, LinkType, Options, Parser, Tag,
 };
 use rustc_ast as ast;
 use rustc_ast::attr::AttributeExt;
 use rustc_ast::util::comments::beautify_doc_string;
-use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::unord::UnordSet;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::DefId;
 use rustc_span::{DUMMY_SP, InnerSpan, Span, Symbol, kw, sym};
@@ -422,7 +424,7 @@ fn parse_links<'md>(doc: &'md str) -> Vec<Box<str>> {
     );
     let mut links = Vec::new();
 
-    let mut refids = FxHashSet::default();
+    let mut refids = UnordSet::default();
 
     while let Some(event) = event_iter.next() {
         match event {
@@ -454,7 +456,7 @@ fn parse_links<'md>(doc: &'md str) -> Vec<Box<str>> {
         }
     }
 
-    for (label, refdef) in event_iter.reference_definitions().iter() {
+    for (label, refdef) in event_iter.reference_definitions().iter().sorted_by_key(|x| x.0) {
         if !refids.contains(label) {
             links.push(preprocess_link(&refdef.dest));
         }

src/librustdoc/html/markdown.rs

@@ -1724,6 +1724,7 @@ pub(crate) fn markdown_links<'md, R>(
     md: &'md str,
     preprocess_link: impl Fn(MarkdownLink) -> Option<R>,
 ) -> Vec<R> {
+    use itertools::Itertools;
     if md.is_empty() {
         return vec![];
     }
@@ -1882,7 +1883,7 @@ pub(crate) fn markdown_links<'md, R>(
     let mut links = Vec::new();
 
     let mut refdefs = FxIndexMap::default();
-    for (label, refdef) in event_iter.reference_definitions().iter() {
+    for (label, refdef) in event_iter.reference_definitions().iter().sorted_by_key(|x| x.0) {
         refdefs.insert(label.to_string(), (false, refdef.dest.to_string(), refdef.span.clone()));
     }