Auto merge of #21809 - servo:features, r=SimonSapin

Only build ports/servo by default (except Android), add `./mach build --libsimpleservo`

Fixes #21314

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/21809)
<!-- Reviewable:end -->

Cargo.toml

@@ -4,11 +4,6 @@ members = [
     "ports/libsimpleservo/",
     "tests/unit/*",
 ]
-default-members = [
-    "ports/servo",
-    "ports/libsimpleservo/",
-    "tests/unit/*",
-]
 exclude = [".cargo"]
 
 [profile.release]

etc/ci/buildbot_steps.yml

@@ -115,6 +115,7 @@ linux-dev:
     - ./mach test-unit
     - python ./etc/memory_reports_over_time.py --test
     - ./mach package --dev
+    - ./mach build --libsimpleservo
     - ./mach build --dev --no-default-features --features default-except-unstable -p servo
     - bash ./etc/ci/lockfile_changed.sh
     - bash ./etc/ci/check_no_panic.sh

ports/servo/non_android_main.rs

@@ -58,6 +58,9 @@ pub mod platform {
     pub fn deinit() {}
 }
 
+#[cfg(not(feature = "unstable"))]
+fn install_crash_handler() {}
+
 #[cfg(feature = "unstable")]
 fn install_crash_handler() {
     use backtrace::Backtrace;

python/servo/build_commands.py

@@ -184,9 +184,14 @@ class MachCommands(CommandBase):
                      default=None,
                      action='store_true',
                      help='Enable debug assertions in release')
+    @CommandArgument('--libsimpleservo',
+                     default=None,
+                     action='store_true',
+                     help='Build the libsimpleservo library instead of the servo executable')
     def build(self, target=None, release=False, dev=False, jobs=None,
               features=None, android=None, no_package=False, verbose=False, very_verbose=False,
-              debug_mozjs=False, params=None, with_debug_assertions=False):
+              debug_mozjs=False, params=None, with_debug_assertions=False,
+              libsimpleservo=False):
 
         opts = params or []
 
@@ -254,6 +259,8 @@ class MachCommands(CommandBase):
         self.ensure_bootstrapped(target=target)
         self.ensure_clobbered()
 
+        self.add_manifest_path(opts, android, libsimpleservo)
+
         if debug_mozjs:
             features += ["debugmozjs"]
 

python/servo/command_base.py

@@ -670,9 +670,21 @@ install them, let us know by filing a bug!")
     def ports_servo_crate(self):
         return path.join(self.context.topdir, "ports", "servo")
 
+    def add_manifest_path(self, args, android=False, libsimpleservo=False):
+        if "--manifest-path" not in args:
+            if libsimpleservo or android:
+                manifest = self.ports_libsimpleservo_manifest()
+            else:
+                manifest = self.ports_servo_manifest()
+            args.append("--manifest-path")
+            args.append(manifest)
+
     def ports_servo_manifest(self):
         return path.join(self.context.topdir, "ports", "servo", "Cargo.toml")
 
+    def ports_libsimpleservo_manifest(self):
+        return path.join(self.context.topdir, "ports", "libsimpleservo", "Cargo.toml")
+
     def servo_features(self):
         """Return a list of optional features to enable for the Servo crate"""
         features = []

python/servo/devenv_commands.py

@@ -42,6 +42,8 @@ class MachCommands(CommandBase):
         if check:
             params = ['check'] + params
 
+        self.add_manifest_path(params)
+
         build_start = time()
         status = self.call_rustup_run(["cargo"] + params, env=env)
         elapsed = time() - build_start