apply the environment to the version query

src/cargo/core/compiler/mod.rs

@@ -1907,7 +1907,7 @@ fn descriptive_pkg_name(name: &str, target: &Target, mode: &CompileMode) -> Stri
 }
 
 /// Applies environment variables from config `[env]` to [`ProcessBuilder`].
-fn apply_env_config(gctx: &crate::GlobalContext, cmd: &mut ProcessBuilder) -> CargoResult<()> {
+pub(crate) fn apply_env_config(gctx: &crate::GlobalContext, cmd: &mut ProcessBuilder) -> CargoResult<()> {
     for (key, value) in gctx.env_config()?.iter() {
         // never override a value that has already been set by cargo
         if cmd.get_envs().contains_key(key) {

src/cargo/util/rustc.rs

@@ -9,6 +9,7 @@ use cargo_util::{paths, ProcessBuilder, ProcessError};
 use serde::{Deserialize, Serialize};
 use tracing::{debug, info, warn};
 
+use crate::core::compiler::apply_env_config;
 use crate::util::interning::InternedString;
 use crate::util::{CargoResult, GlobalContext, StableHasher};
 
@@ -60,6 +61,7 @@ impl Rustc {
         let mut cmd = ProcessBuilder::new(&path)
             .wrapped(workspace_wrapper.as_ref())
             .wrapped(wrapper.as_deref());
+        apply_env_config(gctx, &mut cmd)?;
         cmd.arg("-vV");
         let verbose_version = cache.cached_output(&cmd, 0)?.0;
 

tests/testsuite/cargo_env_config.rs

@@ -193,12 +193,10 @@ fn env_applied_to_target_info_discovery_rustc() {
             r#"
             fn main() {
                 let mut cmd = std::env::args().skip(1).collect::<Vec<_>>();
-                if cmd.get(1).map(|s| &**s) == Some("-vV") {
-                    // This is the version query, not the target info query, so skip this.
-                } else {
-                    let env_test = std::env::var("ENV_TEST").unwrap();
-                    eprintln!("WRAPPER ENV_TEST:{env_test}");
-                }
+                // This will be invoked twice (with `-vV` and with all the `--print`),
+                // make sure the environment variable exists each time.
+                let env_test = std::env::var("ENV_TEST").unwrap();
+                eprintln!("WRAPPER ENV_TEST:{env_test}");
                 let (prog, args) = cmd.split_first().unwrap();
                 let status = std::process::Command::new(prog)
                     .args(args).status().unwrap();