fix: do not panic when failed to parse rustc commit-hash

In some situation the commit-hash in `rustc -vV` output is "unknown".
The debug assertion must not block any progress on others like miri,
so removed and log instead.

Author: weihanglo

src/cargo/util/rustc.rs

@@ -82,17 +82,22 @@ impl Rustc {
                 verbose_version
             )
         })?;
-        let commit_hash = extract("commit-hash: ").ok().map(|hash| {
-            debug_assert!(
-                hash.chars().all(|ch| ch.is_ascii_hexdigit()),
-                "commit hash must be a hex string, got: {hash:?}"
-            );
-            debug_assert!(
-                hash.len() == 40 || hash.len() == 64,
-                "hex string must be generated from sha1 or sha256 (i.e., it must be 40 or 64 characters long)\ngot: {hash:?}"
-            );
-            hash.to_string()
-        });
+        let commit_hash = extract("commit-hash: ").ok()
+            .filter(|hash| {
+                // Ensure that commit hash is always a SHA hex string.
+                // If it is not, like `commit-hash: unknown`,
+                // then treat it as if the entire `commit-hash:` line never exist.
+                if !hash.chars().all(|ch| ch.is_ascii_hexdigit()) {
+                    debug!("commit hash must be a hex string, got: {hash:?}");
+                    return false;
+                }
+                if hash.len() != 40 && hash.len() != 64 {
+                    debug!("hex string must be generated from sha1 or sha256 (i.e., it must be 40 or 64 characters long)\ngot: {hash:?}");
+                    return false;
+                }
+                true
+            })
+            .map(|hash| hash.to_string());
 
         Ok(Rustc {
             path,