From 795a6669f83274ce3ada1046e6c9284b8e900a98 Mon Sep 17 00:00:00 2001
From: Augie Fackler <augie@google.com>
Date: Tue, 18 Mar 2025 16:32:09 -0400
Subject: [PATCH 1/3] rustc_resolve: fix instability in lib.rmeta contents

rust-lang/rust@23032f31c91f2 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                            | 1 +
 compiler/rustc_resolve/Cargo.toml     | 1 +
 compiler/rustc_resolve/src/rustdoc.rs | 3 ++-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index 63a3f5dd03773..67ddac6032b44 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4316,6 +4316,7 @@ name = "rustc_resolve"
 version = "0.0.0"
 dependencies = [
  "bitflags",
+ "itertools",
  "pulldown-cmark 0.11.3",
  "rustc_arena",
  "rustc_ast",
diff --git a/compiler/rustc_resolve/Cargo.toml b/compiler/rustc_resolve/Cargo.toml
index f4771f1af2cfd..9ea9c58cfd17a 100644
--- a/compiler/rustc_resolve/Cargo.toml
+++ b/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" }
diff --git a/compiler/rustc_resolve/src/rustdoc.rs b/compiler/rustc_resolve/src/rustdoc.rs
index 52aaab77ebed6..9fda1eb4dc453 100644
--- a/compiler/rustc_resolve/src/rustdoc.rs
+++ b/compiler/rustc_resolve/src/rustdoc.rs
@@ -1,6 +1,7 @@
 use std::mem;
 use std::ops::Range;
 
+use itertools::Itertools;
 use pulldown_cmark::{
     BrokenLink, BrokenLinkCallback, CowStr, Event, LinkType, Options, Parser, Tag,
 };
@@ -454,7 +455,7 @@ 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));
         }

From 77eb97d9a983f213cff1df7e02a4a96273653482 Mon Sep 17 00:00:00 2001
From: Augie Fackler <augie@google.com>
Date: Thu, 27 Mar 2025 11:59:04 -0400
Subject: [PATCH 2/3] librustdoc: also stabilize iteration order here

---
 src/librustdoc/html/markdown.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index b067dbf750e7d..7606128e9e888 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -1726,6 +1726,7 @@ 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![];
     }
@@ -1884,7 +1885,7 @@ 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()));
     }
 

From 1437dec79942f1367b4cc7756e2f080261c34f3a Mon Sep 17 00:00:00 2001
From: Augie Fackler <augie@google.com>
Date: Thu, 27 Mar 2025 12:39:48 -0400
Subject: [PATCH 3/3] rustc_resolve: prevent iteration of refids for
 completeness

This came up in review, and it should help some future author
not introduce non-deterministic output here.
---
 compiler/rustc_resolve/src/rustdoc.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_resolve/src/rustdoc.rs b/compiler/rustc_resolve/src/rustdoc.rs
index 9fda1eb4dc453..a32fe6990160c 100644
--- a/compiler/rustc_resolve/src/rustdoc.rs
+++ b/compiler/rustc_resolve/src/rustdoc.rs
@@ -8,7 +8,8 @@ use pulldown_cmark::{
 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};
@@ -423,7 +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 {