chore: remove `rustc-workspace-hack`

Co-authored-by: Scott Schafer <schaferjscott@gmail.com>
Co-authored-by: Eric Huss <eric@huss.org>

8 files changed, 4 insertions, 191 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 94de4403c63..358b2f2e924 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2773,7 +2773,6 @@ dependencies = [
 name = "rls"
 version = "2.0.0"
 dependencies = [
- "rustc-workspace-hack",
  "serde",
  "serde_json",
 ]
@@ -2885,11 +2884,8 @@ dependencies = [
 [[package]]
 name = "rustc-workspace-hack"
 version = "1.0.0"
-dependencies = [
- "libc",
- "regex",
- "serde_json",
-]
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc71d2faa173b74b232dedc235e3ee1696581bb132fc116fa3626d6151a1a8fb"
 
 [[package]]
 name = "rustc_abi"
diff --git a/Cargo.toml b/Cargo.toml
index 64ac3990097..a497d7321e0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -100,10 +100,6 @@ miniz_oxide.debug = 0
 object.debug = 0
 
 [patch.crates-io]
-# See comments in `src/tools/rustc-workspace-hack/README.md` for what's going on
-# here
-rustc-workspace-hack = { path = 'src/tools/rustc-workspace-hack' }
-
 # See comments in `library/rustc-std-workspace-core/README.md` for what's going on
 # here
 rustc-std-workspace-core = { path = 'library/rustc-std-workspace-core' }
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 419bcbc63cf..bfdb029951f 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -238,8 +238,6 @@ pub struct Build {
     ci_env: CiEnv,
     delayed_failures: RefCell<Vec<String>>,
     prerelease_version: Cell<Option<u32>>,
-    tool_artifacts:
-        RefCell<HashMap<TargetSelection, HashMap<String, (&'static str, PathBuf, Vec<String>)>>>,
 
     #[cfg(feature = "build-metrics")]
     metrics: metrics::BuildMetrics,
@@ -458,7 +456,6 @@ impl Build {
             ci_env: CiEnv::current(),
             delayed_failures: RefCell::new(Vec::new()),
             prerelease_version: Cell::new(None),
-            tool_artifacts: Default::default(),
 
             #[cfg(feature = "build-metrics")]
             metrics: metrics::BuildMetrics::init(),
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 0d6f1695518..842aa91ad5a 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -1,4 +1,3 @@
-use std::collections::HashSet;
 use std::env;
 use std::fs;
 use std::path::PathBuf;
@@ -120,136 +119,10 @@ impl Step for ToolBuild {
             &self.target,
         );
         builder.info(&msg);
-        let mut duplicates = Vec::new();
-        let is_expected = compile::stream_cargo(builder, cargo, vec![], &mut |msg| {
-            // Only care about big things like the RLS/Cargo for now
-            match tool {
-                "rls" | "clippy-driver" | "miri" | "rustfmt" => {}
-
-                _ => return,
-            }
-            let (id, features, filenames) = match msg {
-                compile::CargoMessage::CompilerArtifact {
-                    package_id,
-                    features,
-                    filenames,
-                    target: _,
-                } => (package_id, features, filenames),
-                _ => return,
-            };
-            let features = features.iter().map(|s| s.to_string()).collect::<Vec<_>>();
-
-            for path in filenames {
-                let val = (tool, PathBuf::from(&*path), features.clone());
-                // we're only interested in deduplicating rlibs for now
-                if val.1.extension().and_then(|s| s.to_str()) != Some("rlib") {
-                    continue;
-                }
-
-                // Don't worry about compiles that turn out to be host
-                // dependencies or build scripts. To skip these we look for
-                // anything that goes in `.../release/deps` but *doesn't* go in
-                // `$target/release/deps`. This ensure that outputs in
-                // `$target/release` are still considered candidates for
-                // deduplication.
-                if let Some(parent) = val.1.parent() {
-                    if parent.ends_with("release/deps") {
-                        let maybe_target = parent
-                            .parent()
-                            .and_then(|p| p.parent())
-                            .and_then(|p| p.file_name())
-                            .and_then(|p| p.to_str())
-                            .unwrap();
-                        if maybe_target != &*target.triple {
-                            continue;
-                        }
-                    }
-                }
-
-                // Record that we've built an artifact for `id`, and if one was
-                // already listed then we need to see if we reused the same
-                // artifact or produced a duplicate.
-                let mut artifacts = builder.tool_artifacts.borrow_mut();
-                let prev_artifacts = artifacts.entry(target).or_default();
-                let prev = match prev_artifacts.get(&*id) {
-                    Some(prev) => prev,
-                    None => {
-                        prev_artifacts.insert(id.to_string(), val);
-                        continue;
-                    }
-                };
-                if prev.1 == val.1 {
-                    return; // same path, same artifact
-                }
-
-                // If the paths are different and one of them *isn't* inside of
-                // `release/deps`, then it means it's probably in
-                // `$target/release`, or it's some final artifact like
-                // `libcargo.rlib`. In these situations Cargo probably just
-                // copied it up from `$target/release/deps/libcargo-xxxx.rlib`,
-                // so if the features are equal we can just skip it.
-                let prev_no_hash = prev.1.parent().unwrap().ends_with("release/deps");
-                let val_no_hash = val.1.parent().unwrap().ends_with("release/deps");
-                if prev.2 == val.2 || !prev_no_hash || !val_no_hash {
-                    return;
-                }
-
-                // ... and otherwise this looks like we duplicated some sort of
-                // compilation, so record it to generate an error later.
-                duplicates.push((id.to_string(), val, prev.clone()));
-            }
+        let is_expected = compile::stream_cargo(builder, cargo, vec![], &mut |_msg| {
+            return;
         });
 
-        if is_expected && !duplicates.is_empty() {
-            eprintln!(
-                "duplicate artifacts found when compiling a tool, this \
-                      typically means that something was recompiled because \
-                      a transitive dependency has different features activated \
-                      than in a previous build:\n"
-            );
-            let (same, different): (Vec<_>, Vec<_>) =
-                duplicates.into_iter().partition(|(_, cur, prev)| cur.2 == prev.2);
-            if !same.is_empty() {
-                eprintln!(
-                    "the following dependencies are duplicated although they \
-                      have the same features enabled:"
-                );
-                for (id, cur, prev) in same {
-                    eprintln!("  {}", id);
-                    // same features
-                    eprintln!("    `{}` ({:?})\n    `{}` ({:?})", cur.0, cur.1, prev.0, prev.1);
-                }
-            }
-            if !different.is_empty() {
-                eprintln!("the following dependencies have different features:");
-                for (id, cur, prev) in different {
-                    eprintln!("  {}", id);
-                    let cur_features: HashSet<_> = cur.2.into_iter().collect();
-                    let prev_features: HashSet<_> = prev.2.into_iter().collect();
-                    eprintln!(
-                        "    `{}` additionally enabled features {:?} at {:?}",
-                        cur.0,
-                        &cur_features - &prev_features,
-                        cur.1
-                    );
-                    eprintln!(
-                        "    `{}` additionally enabled features {:?} at {:?}",
-                        prev.0,
-                        &prev_features - &cur_features,
-                        prev.1
-                    );
-                }
-            }
-            eprintln!();
-            eprintln!(
-                "to fix this you will probably want to edit the local \
-                      src/tools/rustc-workspace-hack/Cargo.toml crate, as \
-                      that will update the dependency graph to ensure that \
-                      these crates all share the same feature set"
-            );
-            panic!("tools should not compile multiple copies of the same crate");
-        }
-
         builder.save_toolstate(
             tool,
             if is_expected { ToolState::TestFail } else { ToolState::BuildFail },
diff --git a/src/tools/rls/Cargo.toml b/src/tools/rls/Cargo.toml
index 92b50bf4cec..b84647eb332 100644
--- a/src/tools/rls/Cargo.toml
+++ b/src/tools/rls/Cargo.toml
@@ -7,7 +7,3 @@ license = "Apache-2.0/MIT"
 [dependencies]
 serde = { version = "1.0.143", features = ["derive"] }
 serde_json = "1.0.83"
-# A noop dependency that changes in the Rust repository, it's a bit of a hack.
-# See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
-# for more information.
-rustc-workspace-hack = "1.0.0"
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
deleted file mode 100644
index 5d5d57fc9ef..00000000000
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ /dev/null
@@ -1,19 +0,0 @@
-[package]
-name = "rustc-workspace-hack"
-version = "1.0.0"
-license = 'MIT OR Apache-2.0'
-description = """
-Hack for the compiler's own build system
-"""
-edition = "2021"
-
-[lib]
-path = "lib.rs"
-
-# For documentation about what this is and why in the world these dependencies
-# are appearing, see `README.md`.
-[dependencies]
-libc = { version = "0.2", features = ["extra_traits"] }
-serde_json = { version = "1.0.31", features = ["unbounded_depth"] }
-# Ensure default features of regex, which are disabled in some scenarios.
-regex = { version = "1.5.6" }
diff --git a/src/tools/rustc-workspace-hack/README.md b/src/tools/rustc-workspace-hack/README.md
deleted file mode 100644
index 3c61470358b..00000000000
--- a/src/tools/rustc-workspace-hack/README.md
+++ /dev/null
@@ -1,25 +0,0 @@
-# `rustc-workspace-hack`
-
-This crate is a bit of a hack to make workspaces in rustc work a bit better.
-The rationale for this existence is a bit subtle, but the general idea is that
-we want commands like `./x.py build src/tools/{clippy,cargo}` to share as
-many dependencies as possible.
-
-Each invocation is a different invocation of Cargo, however. Each time Cargo
-runs a build it will re-resolve the dependency graph, notably selecting
-different features sometimes for each build.
-
-For example, let's say there's a very deep dependency like `winapi` in each of
-these builds. For Cargo, `winapi` has 33 features enabled. In Clippy, however,
-`winapi` has 22 features enabled. This means that building Cargo and then the
-Clippy will actually build winapi twice, which in turn will build duplicates
-of everything that depends on `winapi`. This is bad!
-
-The goal of this crate is to solve this problem and ensure that the resolved
-dependency graph for all of these tools is the same in the various subsets of
-each tool, notably enabling the same features of transitive dependencies.
-
-All tools vendored here depend on the `rustc-workspace-hack` crate on crates.io.
-When on crates.io this crate is an empty crate that is just a noop. We override
-it, however, in this workspace to this crate here, which means we can control
-crates in the dependency graph for each of these tools.
diff --git a/src/tools/rustc-workspace-hack/lib.rs b/src/tools/rustc-workspace-hack/lib.rs
deleted file mode 100644
index 44425d9c15f..00000000000
--- a/src/tools/rustc-workspace-hack/lib.rs
+++ /dev/null
@@ -1 +0,0 @@
-// intentionally left blank