From 88d31906d9e826c79ccf6bfd76a45616dbadd28a Mon Sep 17 00:00:00 2001
From: Vyncint Ng <115854244+vyncint@users.noreply.github.com>
Date: Fri, 28 Aug 2026 21:32:02 +0700
Subject: [PATCH] fix(cargo-oxide): `fmt` no longer builds the backend before
 formatting

`cargo oxide fmt` resolved its context with `resolve_context`, which calls
`backend::find_or_build_backend`: on a checkout with no cached
`librustc_codegen_cuda.so` the command compiled the entire codegen backend --
and in standalone mode cloned it first -- before formatting a single file.

Formatting compiles no device code. `format_all` reads only `workspace_root`,
`codegen_crate` and `examples_dir`; neither it nor `run_cargo_fmt`,
`run_cargo_fmt_manifest`, `run_fmt_command` nor `collect_example_manifests`
takes a `Context` at all, so `backend_so` is unreachable from this path.
`resolve_passive_context` fills those three fields identically in every
discovery branch, so the eager resolver bought nothing.

`doctor`, `clean`, `list` and `update` already resolve passively for the same
reason; `fmt` was the one read-only command left resolving eagerly. Its doc
comment now names it alongside them.

Signed-off-by: Vyncint Ng <115854244+vyncint@users.noreply.github.com>
---
 crates/cargo-oxide/src/commands/context.rs | 4 ++--
 crates/cargo-oxide/src/main.rs             | 7 ++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/crates/cargo-oxide/src/commands/context.rs b/crates/cargo-oxide/src/commands/context.rs
index 7ec0f9a85b..100cc5d01e 100644
--- a/crates/cargo-oxide/src/commands/context.rs
+++ b/crates/cargo-oxide/src/commands/context.rs
@@ -97,8 +97,8 @@ pub fn resolve_context() -> Context {
 /// only located via [`backend::backend_so_candidate`], never built and never
 /// cloned, and an invalid `.cargo/cuda-oxide.toml` degrades to defaults with
 /// a warning instead of exiting (so `doctor` can report it as a failed
-/// check). Passive commands such as `doctor` and `clean` must remain usable
-/// without triggering backend setup or network access.
+/// check). Passive commands such as `doctor`, `clean`, `list` and `fmt` must
+/// remain usable without triggering backend setup or network access.
 /// `run`/`build`/`pipeline`/`setup` still build the backend on demand.
 pub fn resolve_passive_context() -> Context {
     if let Some(workspace_root) = backend::find_workspace_root() {
diff --git a/crates/cargo-oxide/src/main.rs b/crates/cargo-oxide/src/main.rs
index 8f1b2ef349..32bfa3eec8 100644
--- a/crates/cargo-oxide/src/main.rs
+++ b/crates/cargo-oxide/src/main.rs
@@ -1035,7 +1035,12 @@ fn main() {
             commands::list_examples(&ctx, json);
         }
         Commands::Fmt { check } => {
-            let ctx = commands::resolve_context();
+            // Formatting compiles no device code. `format_all` reads only
+            // `workspace_root`, `codegen_crate` and `examples_dir`, which the
+            // passive resolver fills in identically, so eager resolution only
+            // added a backend build -- and a clone on a fresh checkout -- ahead
+            // of the first file being formatted.
+            let ctx = commands::resolve_passive_context();
             commands::format_all(&ctx, check);
         }
         Commands::New { name, async_mode } => {