feat(dist): refine suggestions regarding manifest checksum mismatches

src/dist/mod.rs

@@ -10,7 +10,7 @@ use once_cell::sync::Lazy;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
 use thiserror::Error as ThisError;
-use tracing::info;
+use tracing::{info, warn};
 
 use crate::{
     config::Cfg, currentprocess::Process, errors::RustupError, toolchain::ToolchainName,
@@ -1169,9 +1169,18 @@ pub(crate) async fn dl_v2_manifest(
             Ok(Some((manifest, manifest_hash)))
         }
         Err(any) => {
-            if let Some(RustupError::ChecksumFailed { .. }) = any.downcast_ref::<RustupError>() {
-                // Checksum failed - issue warning to try again later
-                info!("update not yet available, sorry! try again later")
+            if let Some(err @ RustupError::ChecksumFailed { .. }) =
+                any.downcast_ref::<RustupError>()
+            {
+                // Manifest checksum mismatched.
+                // This might indicate a transient state during an update
+                // on the official release server
+                // (see <https://github.com/rust-lang/rustup/issues/3390>)
+                // or a misconfiguration of a third-party release server
+                // (see <https://github.com/rust-lang/rustup/issues/3885>).
+                warn!("{err}");
+                info!("if you are on the official release server, this is most likely due to an update happening right now, please try again later");
+                info!("if you are on a third-party release server, this might indicate a problem with the server's configuration");
             }
             Err(any)
         }

tests/suite/cli_v2.rs

@@ -358,10 +358,7 @@ async fn bad_sha_on_manifest() {
     rustup::utils::raw::write_file(&sha_file, &sha_str).unwrap();
     // We fail because the sha is bad, but we should emit the special message to that effect.
     cx.config
-        .expect_err(
-            &["rustup", "default", "nightly"],
-            "update not yet available",
-        )
+        .expect_err(&["rustup", "default", "nightly"], "please try again later")
         .await;
 }