panic in CI or with CROSS_NO_WARNINGS=1 if there are warnings

Author: Emilgardis

Cargo.lock

@@ -48,6 +48,7 @@ walkdir = { version = "2.3.2", optional = true }
 tempfile = "3.3.0"
 owo-colors = { version = "3.5.0", features = ["supports-colors"] }
 semver = "1.0.16"
+is_ci = "1.1.1"
 
 [target.'cfg(not(windows))'.dependencies]
 nix = { version = "0.26.2", default-features = false, features = ["user"] }

Cargo.toml

@@ -6,7 +6,7 @@ use std::{
 };
 
 use cross::{
-    cargo, cli, rustc,
+    cargo, cli, config, rustc,
     shell::{self, Verbosity},
     OutputExt, Subcommand,
 };
@@ -21,7 +21,11 @@ pub fn main() -> cross::Result<()> {
     let mut msg_info = shell::MessageInfo::create(args.verbose, args.quiet, args.color.as_deref())?;
     let status = match cross::run(args, target_list, &mut msg_info)? {
         Some(status) => status,
-        None => {
+        None if env::var("CROSS_NO_WARNINGS")
+            .map(|env| config::bool_from_envvar(&env))
+            .unwrap_or_else(|_| is_ci::uncached())
+            && !msg_info.has_warned =>
+        {
             // if we fallback to the host cargo, use the same invocation that was made to cross
             let argv: Vec<String> = env::args().skip(1).collect();
             msg_info.note("Falling back to `cargo` on the host.")?;
@@ -42,6 +46,11 @@ pub fn main() -> cross::Result<()> {
                 _ => cargo::run(&argv, &mut msg_info)?,
             }
         }
+        None => {
+            msg_info.error("Errors encountered before cross compilation, aborting.")?;
+            msg_info.note("Disable this with `CROSS_NO_WARNINGS=0`")?;
+            std::process::exit(1);
+        }
     };
     let code = status
         .code()

src/bin/cross.rs

@@ -140,6 +140,7 @@ pub struct MessageInfo {
     pub stdout_needs_erase: bool,
     pub stderr_needs_erase: bool,
     pub cross_debug: bool,
+    pub has_warned: bool,
 }
 
 impl MessageInfo {
@@ -153,6 +154,7 @@ impl MessageInfo {
                 .as_deref()
                 .map(bool_from_envvar)
                 .unwrap_or_default(),
+            has_warned: false,
         }
     }
 
@@ -231,13 +233,15 @@ impl MessageInfo {
     /// prints a red 'error' message.
     #[track_caller]
     pub fn error<T: fmt::Display>(&mut self, message: T) -> Result<()> {
+        self.has_warned = true;
         self.stderr_check_erase()?;
         status!(@stderr cross_prefix!("error"), Some(&message), red, self)
     }
 
     /// prints an amber 'warning' message.
     #[track_caller]
     pub fn warn<T: fmt::Display>(&mut self, message: T) -> Result<()> {
+        self.has_warned = true;
         match self.verbosity {
             Verbosity::Quiet => Ok(()),
             _ => status!(@stderr