clippy: allow usages of std::env::{var,var_os} by exceptions

build.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::disallowed_methods)]
+
 use flate2::{Compression, GzBuilder};
 use std::ffi::OsStr;
 use std::fs;

src/cargo/core/compiler/custom_build.rs

@@ -410,6 +410,7 @@ fn build_work(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Job> {
                 // If we're opting into backtraces, mention that build dependencies' backtraces can
                 // be improved by requesting debuginfo to be built, if we're not building with
                 // debuginfo already.
+                #[allow(clippy::disallowed_methods)]
                 if let Ok(show_backtraces) = std::env::var("RUST_BACKTRACE") {
                     if !built_with_debuginfo && show_backtraces != "0" {
                         build_error_context.push_str(&format!(
@@ -727,6 +728,7 @@ impl BuildOutput {
                                 None => return false,
                                 Some(n) => n,
                             };
+                            #[allow(clippy::disallowed_methods)]
                             std::env::var("RUSTC_BOOTSTRAP")
                                 .map_or(false, |var| var.split(',').any(|s| s == name))
                         };

src/cargo/core/features.rs

@@ -1173,9 +1173,11 @@ impl CliUnstable {
 
 /// Returns the current release channel ("stable", "beta", "nightly", "dev").
 pub fn channel() -> String {
+    #[allow(clippy::disallowed_methods)]
     if let Ok(override_channel) = env::var("__CARGO_TEST_CHANNEL_OVERRIDE_DO_NOT_USE_THIS") {
         return override_channel;
     }
+    #[allow(clippy::disallowed_methods)]
     if let Ok(staging) = env::var("RUSTC_BOOTSTRAP") {
         if staging == "1" {
             return "dev".to_string();

src/cargo/core/resolver/types.rs

@@ -31,6 +31,7 @@ impl ResolverProgress {
             // Architectures that do not have a modern processor, hardware emulation, etc.
             // In the test code we have `slow_cpu_multiplier`, but that is not accessible here.
             #[cfg(debug_assertions)]
+            #[allow(clippy::disallowed_methods)]
             slow_cpu_multiplier: std::env::var("CARGO_TEST_SLOW_CPU_MULTIPLIER")
                 .ok()
                 .and_then(|m| m.parse().ok())

src/cargo/core/shell.rs

@@ -17,6 +17,7 @@ impl TtyWidth {
     /// Returns the width of the terminal to use for diagnostics (which is
     /// relayed to rustc via `--diagnostic-width`).
     pub fn diagnostic_terminal_width(&self) -> Option<usize> {
+        #[allow(clippy::disallowed_methods)]
         if let Ok(width) = std::env::var("__CARGO_TEST_TTY_WIDTH_DO_NOT_USE_THIS") {
             return Some(width.parse().unwrap());
         }

src/cargo/core/source/source_id.rs

@@ -428,9 +428,12 @@ impl SourceId {
             _ => return false,
         }
         let url = self.inner.url.as_str();
-        url == CRATES_IO_INDEX
-            || url == CRATES_IO_HTTP_INDEX
-            || std::env::var("__CARGO_TEST_CRATES_IO_URL_DO_NOT_USE_THIS").as_deref() == Ok(url)
+        if url == CRATES_IO_INDEX || url == CRATES_IO_HTTP_INDEX {
+            true
+        } else {
+            #[allow(clippy::disallowed_methods)]
+            std::env::var("__CARGO_TEST_CRATES_IO_URL_DO_NOT_USE_THIS").map_or(false, |v| v == url)
+        }
     }
 
     /// Hashes `self`.

src/cargo/ops/fix.rs

@@ -339,6 +339,7 @@ to prevent this issue from happening.
 /// Returns `None` if `fix` is not being run (not in proxy mode). Returns
 /// `Some(...)` if in `fix` proxy mode
 pub fn fix_get_proxy_lock_addr() -> Option<String> {
+    #[allow(clippy::disallowed_methods)]
     env::var(FIX_ENV).ok()
 }
 
@@ -847,8 +848,10 @@ impl FixArgs {
         }
 
         let file = file.ok_or_else(|| anyhow::anyhow!("could not find .rs file in rustc args"))?;
+        #[allow(clippy::disallowed_methods)]
         let idioms = env::var(IDIOMS_ENV).is_ok();
 
+        #[allow(clippy::disallowed_methods)]
         let prepare_for_edition = env::var(EDITION_ENV).ok().map(|_| {
             enabled_edition
                 .unwrap_or(Edition::Edition2015)

src/cargo/util/job.rs

@@ -32,6 +32,7 @@ mod imp {
         // when-cargo-is-killed-subprocesses-are-also-killed, but that requires
         // one cargo spawned to become its own session leader, so we do that
         // here.
+        #[allow(clippy::disallowed_methods)]
         if env::var("__CARGO_TEST_SETSID_PLEASE_DONT_USE_ELSEWHERE").is_ok() {
             libc::setsid();
         }

src/cargo/util/profile.rs

@@ -22,6 +22,7 @@ pub struct Profiler {
 }
 
 fn enabled_level() -> Option<usize> {
+    #[allow(clippy::disallowed_methods)]
     env::var("CARGO_PROFILE").ok().and_then(|s| s.parse().ok())
 }