rust: silence unknown warnings for the sake of old compilers

Occasionally, we may need to silence warnings and clippy lints that
were only introduced in newer Rust compiler versions.  However, this
would fail when compiling with an older rustc:

error: unknown lint: `non_local_definitions`
   --> rust/qemu-api/rust-qemu-api-tests.p/structured/offset_of.rs:79:17

So by default we need to block the unknown_lints warning.  To avoid
misspelled lints or other similar issues, re-enable it in the CI job
that uses nightly rust.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/.gitlab-ci.d/buildtest.yml b/.gitlab-ci.d/buildtest.yml
index 4800aed04bcf142f881e13f80118dc07a81c57ce..336223484d8470afe2f9c059b6724f6583938c25 100644 (file)
--- a/.gitlab-ci.d/buildtest.yml
+++ b/.gitlab-ci.d/buildtest.yml
@@ -128,7 +128,7 @@ build-system-fedora-rust-nightly:
     job: amd64-fedora-rust-nightly-container
   variables:
     IMAGE: fedora-rust-nightly
-    CONFIGURE_ARGS: --disable-docs --enable-rust
+    CONFIGURE_ARGS: --disable-docs --enable-rust --enable-strict-rust-lints
     TARGETS: aarch64-softmmu
     MAKE_CHECK_ARGS: check-build
   allow_failure: true

diff --git a/meson.build b/meson.build
index 8ee4b7dd15a8f90dd8bc571296c1647da57980f9..01d0d542f2246d910d06db40a4206f020a5fbb5d 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -3346,6 +3346,14 @@ if have_rust and have_system
   # Prohibit code that is forbidden in Rust 2024
   rustc_args += ['-D', 'unsafe_op_in_unsafe_fn']
 
+  # Occasionally, we may need to silence warnings and clippy lints that
+  # were only introduced in newer Rust compiler versions.  Do not croak
+  # in that case; a CI job with rust_strict_lints == true ensures that
+  # we do not have misspelled allow() attributes.
+  if not get_option('strict_rust_lints')
+    rustc_args += ['-A', 'unknown_lints']
+  endif
+
   # Apart from procedural macros, our Rust executables will often link
   # with C code, so include all the libraries that C code needs.  This
   # is safe; https://github.com/rust-lang/rust/pull/54675 says that

diff --git a/meson_options.txt b/meson_options.txt
index 24bf0090560e8f371d680d947adbc009b542451e..502efe605bc13a9b1f29e8e28fe1beb00e871720 100644 (file)
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -378,3 +378,5 @@ option('x86_version', type : 'combo', choices : ['0', '1', '2', '3', '4'], value
 
 option('rust', type: 'feature', value: 'disabled',
        description: 'Rust support')
+option('strict_rust_lints', type: 'boolean', value: false,
+       description: 'Enable stricter set of Rust warnings')

diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 6f2bb08ecd8f5eb755a11043a329f1eb16b9a4f0..f9693d226bacb405d7e61ce3317e20446f2b35e4 100644 (file)
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -47,6 +47,8 @@ meson_options_help() {
   printf "%s\n" '                           getrandom()'
   printf "%s\n" '  --enable-safe-stack      SafeStack Stack Smash Protection (requires'
   printf "%s\n" '                           clang/llvm and coroutine backend ucontext)'
+  printf "%s\n" '  --enable-strict-rust-lints'
+  printf "%s\n" '                           Enable stricter set of Rust warnings'
   printf "%s\n" '  --enable-strip           Strip targets on install'
   printf "%s\n" '  --enable-tcg-interpreter TCG with bytecode interpreter (slow)'
   printf "%s\n" '  --enable-trace-backends=CHOICES'
@@ -493,6 +495,8 @@ _meson_option_parse() {
     --disable-spice-protocol) printf "%s" -Dspice_protocol=disabled ;;
     --enable-stack-protector) printf "%s" -Dstack_protector=enabled ;;
     --disable-stack-protector) printf "%s" -Dstack_protector=disabled ;;
+    --enable-strict-rust-lints) printf "%s" -Dstrict_rust_lints=true ;;
+    --disable-strict-rust-lints) printf "%s" -Dstrict_rust_lints=false ;;
     --enable-strip) printf "%s" -Dstrip=true ;;
     --disable-strip) printf "%s" -Dstrip=false ;;
     --sysconfdir=*) quote_sh "-Dsysconfdir=$2" ;;