Use CARGO_PRIMARY_PACKAGE to skip dependencies

See also rust-lang/cargo#8758 and rust-lang/rust-clippy#6188

Author: fpoli

prusti-tests/tests/compiletest.rs

@@ -146,6 +146,8 @@ fn run_verification_core_proof(group_name: &str, filter: &Option<String>) {
 }
 
 fn test_runner(_tests: &[&()]) {
+    env::set_var("PRUSTI_TESTS", "1");
+
     // Spawn server process as child (so it stays around until main function terminates)
     let server_address = ServerSideService::spawn_off_thread();
     env::set_var("PRUSTI_SERVER_ADDRESS", server_address.to_string());

prusti/src/arg_value.rs

@@ -30,7 +30,6 @@ extern crate prusti_common;
 
 mod callbacks;
 mod verifier;
-mod arg_value;
 
 use log::debug;
 use std::{env, panic, borrow::Cow, path::PathBuf};
@@ -40,7 +39,6 @@ use lazy_static::lazy_static;
 use callbacks::PrustiCompilerCalls;
 use rustc_middle::ty::TyCtxt;
 use prusti_common::config;
-use arg_value::arg_value;
 
 /// Link to report Prusti bugs
 const BUG_REPORT_URL: &str = "https://github.com/viperproject/prusti-dev/issues/new";
@@ -125,8 +123,11 @@ fn main() {
 
     // If the environment asks us to actually be rustc, then do that.
     // If cargo is compiling a dependency, then be rustc.
+    let is_prusti_test = env::var("PRUSTI_TESTS").is_ok();
+    let is_cargo_running = env::var("CARGO_PKG_NAME").is_ok();
+    let in_primary_package = env::var("CARGO_PRIMARY_PACKAGE").is_ok();
     let prusti_be_rustc = config::be_rustc()
-        || arg_value(&rustc_args, "--cap-lints", |val| val == "allow").is_some();
+        || (!is_prusti_test && is_cargo_running && !in_primary_package);
     if prusti_be_rustc {
         rustc_driver::main();
     }