Add -Z configurable-env to gate [env] usage

Added the `-Z configurable-env` option which controls whether the data from the [env] section is used. Updated the tests to pass the flag and to masquerade as the nightly cargo.

Author: wickerwaka

src/cargo/core/compiler/compilation.rs

@@ -340,10 +340,12 @@ impl<'cfg> Compilation<'cfg> {
             .env("CARGO_PKG_AUTHORS", &pkg.authors().join(":"))
             .cwd(pkg.root());
 
-        // Apply any environment variables from the config
-        for (key, value) in self.config.env_config()?.iter() {
-            if value.is_force() || cmd.get_env(&key).is_none() {
-                cmd.env(&key, value.resolve(&self.config));
+        if self.config.cli_unstable().configurable_env {
+            // Apply any environment variables from the config
+            for (key, value) in self.config.env_config()?.iter() {
+                if value.is_force() || cmd.get_env(&key).is_none() {
+                    cmd.env(&key, value.resolve(&self.config));
+                }
             }
         }
 

src/cargo/core/features.rs

@@ -444,6 +444,7 @@ pub struct CliUnstable {
     pub weak_dep_features: bool,
     pub extra_link_arg: bool,
     pub credential_process: bool,
+    pub configurable_env: bool,
 }
 
 const STABILIZED_COMPILE_PROGRESS: &str = "The progress bar is now always \
@@ -598,6 +599,7 @@ impl CliUnstable {
             "doctest-xcompile" => self.doctest_xcompile = parse_empty(k, v)?,
             "panic-abort-tests" => self.panic_abort_tests = parse_empty(k, v)?,
             "jobserver-per-rustc" => self.jobserver_per_rustc = parse_empty(k, v)?,
+            "configurable-env" => self.configurable_env = parse_empty(k, v)?,
             "features" => {
                 // For now this is still allowed (there are still some
                 // unstable options like "compare"). This should be removed at

tests/testsuite/cargo_env_config.rs

@@ -25,7 +25,8 @@ fn env_basic() {
         )
         .build();
 
-    p.cargo("run")
+    p.cargo("run -Zconfigurable-env")
+        .masquerade_as_nightly_cargo()
         .with_stdout_contains("compile-time:Hello")
         .with_stdout_contains("run-time:Hello")
         .run();
@@ -51,7 +52,8 @@ fn env_invalid() {
         )
         .build();
 
-    p.cargo("build")
+    p.cargo("build -Zconfigurable-env")
+        .masquerade_as_nightly_cargo()
         .with_status(101)
         .with_stderr_contains("[..]`env.ENV_TEST_BOOL` expected a string, but found a boolean")
         .run();
@@ -81,7 +83,8 @@ fn env_force() {
         )
         .build();
 
-    p.cargo("run")
+    p.cargo("run -Zconfigurable-env")
+        .masquerade_as_nightly_cargo()
         .env("ENV_TEST_FORCED", "from-env")
         .env("ENV_TEST_UNFORCED", "from-env")
         .with_stdout_contains("ENV_TEST_FORCED:from-config")
@@ -117,5 +120,7 @@ fn env_relative() {
         )
         .build();
 
-    p.cargo("run").run();
+    p.cargo("run -Zconfigurable-env")
+        .masquerade_as_nightly_cargo()
+        .run();
 }