Add a warning for invalid cfgs

Signed-off-by: hi-rustin <[email protected]>

Author: Rustin170506

crates/cargo-platform/src/cfg.rs

@@ -81,6 +81,15 @@ impl CfgExpr {
         }
     }
 
+    pub fn is_valid_key(key: &str) -> bool {
+        if key.starts_with("cfg(") && key.ends_with(')') {
+            let cfg = &key[4..key.len() - 1];
+            CfgExpr::from_str(cfg).is_ok()
+        } else {
+            false
+        }
+    }
+
     pub fn matches(&self, cfg: &[Cfg]) -> bool {
         match *self {
             CfgExpr::Not(ref e) => !e.matches(cfg),

src/cargo/core/compiler/compilation.rs

@@ -5,6 +5,7 @@ use std::path::PathBuf;
 
 use cargo_platform::CfgExpr;
 use cargo_util::{paths, ProcessBuilder};
+use im_rc::HashSet;
 
 use super::BuildContext;
 use crate::core::compiler::{CompileKind, Metadata, Unit};
@@ -398,14 +399,22 @@ fn target_runner(
         return Ok(Some((path, v.args)));
     }
 
+    let mut invalid_cfgs: HashSet<String> = HashSet::default();
     // try target.'cfg(...)'.runner
     let target_cfg = bcx.target_data.info(kind).cfg();
     let mut cfgs = bcx
         .config
         .target_cfgs()?
         .iter()
         .filter_map(|(key, cfg)| cfg.runner.as_ref().map(|runner| (key, runner)))
-        .filter(|(key, _runner)| CfgExpr::matches_key(key, target_cfg));
+        .filter(|(key, _runner)| {
+            if !CfgExpr::is_valid_key(key) {
+                invalid_cfgs.insert(key.to_string());
+                return false;
+            }
+            CfgExpr::matches_key(key, target_cfg)
+        });
+
     let matching_runner = cfgs.next();
     if let Some((key, runner)) = cfgs.next() {
         anyhow::bail!(
@@ -418,6 +427,13 @@ fn target_runner(
             runner.definition
         );
     }
+    if !invalid_cfgs.is_empty() {
+        bcx.config.shell().warn(format!(
+            "invalid target configuration key{}: {}",
+            if invalid_cfgs.len() == 1 { "" } else { "s" },
+            invalid_cfgs.into_iter().collect::<Vec<_>>().join(", ")
+        ))?;
+    }
     Ok(matching_runner.map(|(_k, runner)| {
         (
             runner.val.path.clone().resolve_program(bcx.config),