Auto merge of #11130 - Muscraft:use-ready-macro, r=Eh2406

switch to `std::task::ready!()` where possible

In Rust 1.64.0, [`std::task::ready`](https://doc.rust-lang.org/stable/std/task/macro.ready.html) was [stabilized](https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#stabilized-apis). Using `ready!()` can make what is happening clearer in the code as it expands to roughly:
```rust
let num = match fut.poll(cx) {
    Poll::Ready(t) => t,
    Poll::Pending => return Poll::Pending,
};
```
This PR replaces places using `Poll::Pending => return Poll::Pending`  with `ready!()` where appropriate.

I was unsure about how useful the new macro would be in one place in [`cargo/registry/index.rs`](https://github.com/rust-lang/cargo/blob/247ca7fd04e5c7cc383bcac7d72316e98fbea2bc/src/cargo/sources/registry/index.rs#L425-L429), so I left it out and will add it in if needed.

Close #11128

r? `@Eh2406`

Author: bors

src/cargo/core/registry.rs

@@ -1,5 +1,5 @@
 use std::collections::{HashMap, HashSet};
-use std::task::Poll;
+use std::task::{ready, Poll};
 
 use crate::core::PackageSet;
 use crate::core::{Dependency, PackageId, QueryKind, Source, SourceId, SourceMap, Summary};
@@ -482,10 +482,7 @@ impl<'cfg> PackageRegistry<'cfg> {
         for &s in self.overrides.iter() {
             let src = self.sources.get_mut(s).unwrap();
             let dep = Dependency::new_override(dep.package_name(), s);
-            let mut results = match src.query_vec(&dep, QueryKind::Exact) {
-                Poll::Ready(results) => results?,
-                Poll::Pending => return Poll::Pending,
-            };
+            let mut results = ready!(src.query_vec(&dep, QueryKind::Exact))?;
             if !results.is_empty() {
                 return Poll::Ready(Ok(Some(results.remove(0))));
             }
@@ -580,10 +577,7 @@ impl<'cfg> Registry for PackageRegistry<'cfg> {
         assert!(self.patches_locked);
         let (override_summary, n, to_warn) = {
             // Look for an override and get ready to query the real source.
-            let override_summary = match self.query_overrides(dep) {
-                Poll::Ready(override_summary) => override_summary?,
-                Poll::Pending => return Poll::Pending,
-            };
+            let override_summary = ready!(self.query_overrides(dep))?;
 
             // Next up on our list of candidates is to check the `[patch]`
             // section of the manifest. Here we look through all patches
@@ -880,23 +874,17 @@ fn summary_for_patch(
     // No summaries found, try to help the user figure out what is wrong.
     if let Some(locked) = locked {
         // Since the locked patch did not match anything, try the unlocked one.
-        let orig_matches = match source.query_vec(orig_patch, QueryKind::Exact) {
-            Poll::Pending => return Poll::Pending,
-            Poll::Ready(deps) => deps,
-        }
-        .unwrap_or_else(|e| {
-            log::warn!(
-                "could not determine unlocked summaries for dep {:?}: {:?}",
-                orig_patch,
-                e
-            );
-            Vec::new()
-        });
+        let orig_matches =
+            ready!(source.query_vec(orig_patch, QueryKind::Exact)).unwrap_or_else(|e| {
+                log::warn!(
+                    "could not determine unlocked summaries for dep {:?}: {:?}",
+                    orig_patch,
+                    e
+                );
+                Vec::new()
+            });
 
-        let summary = match summary_for_patch(orig_patch, &None, orig_matches, source) {
-            Poll::Pending => return Poll::Pending,
-            Poll::Ready(summary) => summary?,
-        };
+        let summary = ready!(summary_for_patch(orig_patch, &None, orig_matches, source))?;
 
         // The unlocked version found a match. This returns a value to
         // indicate that this entry should be unlocked.
@@ -905,18 +893,15 @@ fn summary_for_patch(
     // Try checking if there are *any* packages that match this by name.
     let name_only_dep = Dependency::new_override(orig_patch.package_name(), orig_patch.source_id());
 
-    let name_summaries = match source.query_vec(&name_only_dep, QueryKind::Exact) {
-        Poll::Pending => return Poll::Pending,
-        Poll::Ready(deps) => deps,
-    }
-    .unwrap_or_else(|e| {
-        log::warn!(
-            "failed to do name-only summary query for {:?}: {:?}",
-            name_only_dep,
-            e
-        );
-        Vec::new()
-    });
+    let name_summaries =
+        ready!(source.query_vec(&name_only_dep, QueryKind::Exact)).unwrap_or_else(|e| {
+            log::warn!(
+                "failed to do name-only summary query for {:?}: {:?}",
+                name_only_dep,
+                e
+            );
+            Vec::new()
+        });
     let mut vers = name_summaries
         .iter()
         .map(|summary| summary.version())

src/cargo/sources/registry/http_remote.rs

@@ -19,7 +19,7 @@ use std::collections::{HashMap, HashSet};
 use std::fs::{self, File};
 use std::path::{Path, PathBuf};
 use std::str;
-use std::task::Poll;
+use std::task::{ready, Poll};
 use std::time::Duration;
 use url::Url;
 
@@ -383,10 +383,7 @@ impl<'cfg> RegistryData for HttpRegistry<'cfg> {
 
         // Load the registry config.
         if self.registry_config.is_none() && path != Path::new("config.json") {
-            match self.config()? {
-                Poll::Ready(_) => {}
-                Poll::Pending => return Poll::Pending,
-            }
+            ready!(self.config()?);
         }
 
         let mut handle = ops::http_handle(self.config)?;
@@ -515,11 +512,11 @@ impl<'cfg> RegistryData for HttpRegistry<'cfg> {
             }
         }
 
-        match self.load(Path::new(""), Path::new("config.json"), None)? {
-            Poll::Ready(LoadResponse::Data {
+        match ready!(self.load(Path::new(""), Path::new("config.json"), None)?) {
+            LoadResponse::Data {
                 raw_data,
                 index_version: _,
-            }) => {
+            } => {
                 trace!("config loaded");
                 self.registry_config = Some(serde_json::from_slice(&raw_data)?);
                 if paths::create_dir_all(&config_json_path.parent().unwrap()).is_ok() {
@@ -529,13 +526,12 @@ impl<'cfg> RegistryData for HttpRegistry<'cfg> {
                 }
                 Poll::Ready(Ok(self.registry_config.clone()))
             }
-            Poll::Ready(LoadResponse::NotFound) => {
+            LoadResponse::NotFound => {
                 Poll::Ready(Err(anyhow::anyhow!("config.json not found in registry")))
             }
-            Poll::Ready(LoadResponse::CacheValid) => {
+            LoadResponse::CacheValid => {
                 panic!("config.json is not stored in the index cache")
             }
-            Poll::Pending => Poll::Pending,
         }
     }
 

src/cargo/sources/registry/index.rs

@@ -80,7 +80,7 @@ use std::fs;
 use std::io::ErrorKind;
 use std::path::Path;
 use std::str;
-use std::task::Poll;
+use std::task::{ready, Poll};
 
 /// Crates.io treats hyphen and underscores as interchangeable, but the index and old Cargo do not.
 /// Therefore, the index must store uncanonicalized version of the name so old Cargo's can find it.
@@ -268,10 +268,7 @@ impl<'cfg> RegistryIndex<'cfg> {
     pub fn hash(&mut self, pkg: PackageId, load: &mut dyn RegistryData) -> Poll<CargoResult<&str>> {
         let req = OptVersionReq::exact(pkg.version());
         let summary = self.summaries(pkg.name(), &req, load)?;
-        let summary = match summary {
-            Poll::Ready(mut summary) => summary.next(),
-            Poll::Pending => return Poll::Pending,
-        };
+        let summary = ready!(summary).next();
         Poll::Ready(Ok(summary
             .ok_or_else(|| internal(format!("no hash listed for {}", pkg)))?
             .summary
@@ -302,10 +299,7 @@ impl<'cfg> RegistryIndex<'cfg> {
         // has run previously this will parse a Cargo-specific cache file rather
         // than the registry itself. In effect this is intended to be a quite
         // cheap operation.
-        let summaries = match self.load_summaries(name, load)? {
-            Poll::Ready(summaries) => summaries,
-            Poll::Pending => return Poll::Pending,
-        };
+        let summaries = ready!(self.load_summaries(name, load)?);
 
         // Iterate over our summaries, extract all relevant ones which match our
         // version requirement, and then parse all corresponding rows in the
@@ -422,19 +416,19 @@ impl<'cfg> RegistryIndex<'cfg> {
         f: &mut dyn FnMut(Summary),
     ) -> Poll<CargoResult<()>> {
         if self.config.offline() {
-            match self.query_inner_with_online(dep, load, yanked_whitelist, f, false)? {
-                Poll::Ready(0) => {}
-                Poll::Ready(_) => return Poll::Ready(Ok(())),
-                Poll::Pending => return Poll::Pending,
-            }
-            // If offline, and there are no matches, try again with online.
+            // This should only return `Poll::Ready(Ok(()))` if there is at least 1 match.
+            //
+            // If there are 0 matches it should fall through and try again with online.
             // This is necessary for dependencies that are not used (such as
             // target-cfg or optional), but are not downloaded. Normally the
             // build should succeed if they are not downloaded and not used,
             // but they still need to resolve. If they are actually needed
             // then cargo will fail to download and an error message
             // indicating that the required dependency is unavailable while
             // offline will be displayed.
+            if ready!(self.query_inner_with_online(dep, load, yanked_whitelist, f, false)?) > 0 {
+                return Poll::Ready(Ok(()));
+            }
         }
         self.query_inner_with_online(dep, load, yanked_whitelist, f, true)
             .map_ok(|_| ())
@@ -450,10 +444,7 @@ impl<'cfg> RegistryIndex<'cfg> {
     ) -> Poll<CargoResult<usize>> {
         let source_id = self.source_id;
 
-        let summaries = match self.summaries(dep.package_name(), dep.version_req(), load)? {
-            Poll::Ready(summaries) => summaries,
-            Poll::Pending => return Poll::Pending,
-        };
+        let summaries = ready!(self.summaries(dep.package_name(), dep.version_req(), load))?;
 
         let summaries = summaries
             // First filter summaries for `--offline`. If we're online then
@@ -582,10 +573,7 @@ impl Summaries {
             Err(e) => log::debug!("cache missing for {:?} error: {}", relative, e),
         }
 
-        let response = match load.load(root, relative, index_version.as_deref())? {
-            Poll::Pending => return Poll::Pending,
-            Poll::Ready(response) => response,
-        };
+        let response = ready!(load.load(root, relative, index_version.as_deref())?);
 
         match response {
             LoadResponse::CacheValid => {

src/cargo/sources/registry/remote.rs

@@ -15,7 +15,7 @@ use std::fs::File;
 use std::mem;
 use std::path::Path;
 use std::str;
-use std::task::Poll;
+use std::task::{ready, Poll};
 
 /// A remote registry is a registry that lives at a remote URL (such as
 /// crates.io). The git index is cloned locally, and `.crate` files are
@@ -236,13 +236,12 @@ impl<'cfg> RegistryData for RemoteRegistry<'cfg> {
         debug!("loading config");
         self.prepare()?;
         self.config.assert_package_cache_locked(&self.index_path);
-        match self.load(Path::new(""), Path::new("config.json"), None)? {
-            Poll::Ready(LoadResponse::Data { raw_data, .. }) => {
+        match ready!(self.load(Path::new(""), Path::new("config.json"), None)?) {
+            LoadResponse::Data { raw_data, .. } => {
                 trace!("config loaded");
                 Poll::Ready(Ok(Some(serde_json::from_slice(&raw_data)?)))
             }
-            Poll::Ready(_) => Poll::Ready(Ok(None)),
-            Poll::Pending => Poll::Pending,
+            _ => Poll::Ready(Ok(None)),
         }
     }