Auto merge of #7386 - alexcrichton:less-env-leak, r=ehuss

Remove all `CARGO_*` env vars in tests

Usage of `CARGO_PROFILE_*` is generating unexpected warnings in tests in
rust-lang/rust#64316 so let's just blanket remove every env var that has
a `CARGO_*` prefix which generally means Cargo-specific env vars. Tests
practically all assume that they have blank configs right now.

Author: bors

crates/cargo-test-support/src/lib.rs

@@ -1694,8 +1694,17 @@ pub fn process<T: AsRef<OsStr>>(t: T) -> cargo::util::ProcessBuilder {
 
 fn _process(t: &OsStr) -> cargo::util::ProcessBuilder {
     let mut p = cargo::util::process(t);
+
+    // In general just clear out all cargo-specific configuration already in the
+    // environment. Our tests all assume a "default configuration" unless
+    // specified otherwise.
+    for (k, _v) in env::vars() {
+        if k.starts_with("CARGO_") {
+            p.env_remove(&k);
+        }
+    }
+
     p.cwd(&paths::root())
-        .env_remove("CARGO_HOME")
         .env("HOME", paths::home())
         .env("CARGO_HOME", paths::home().join(".cargo"))
         .env("__CARGO_TEST_ROOT", paths::root())
@@ -1707,10 +1716,6 @@ fn _process(t: &OsStr) -> cargo::util::ProcessBuilder {
         // stable channel yet. Once incremental support hits the stable compiler we
         // can switch this to one and then fix the tests.
         .env("CARGO_INCREMENTAL", "0")
-        // This env var can switch the git backend from libgit2 to git2-curl, which
-        // can tweak error messages and cause some tests to fail, so let's forcibly
-        // remove it.
-        .env_remove("CARGO_HTTP_CHECK_REVOKE")
         .env_remove("__CARGO_DEFAULT_LIB_METADATA")
         .env_remove("RUSTC")
         .env_remove("RUSTDOC")
@@ -1722,12 +1727,10 @@ fn _process(t: &OsStr) -> cargo::util::ProcessBuilder {
         .env_remove("USER") // not set on some rust-lang docker images
         .env_remove("MFLAGS")
         .env_remove("MAKEFLAGS")
-        .env_remove("CARGO_MAKEFLAGS")
         .env_remove("GIT_AUTHOR_NAME")
         .env_remove("GIT_AUTHOR_EMAIL")
         .env_remove("GIT_COMMITTER_NAME")
         .env_remove("GIT_COMMITTER_EMAIL")
-        .env_remove("CARGO_TARGET_DIR") // we assume 'target'
         .env_remove("MSYSTEM"); // assume cmd.exe everywhere on windows
     p
 }