Bug 1823598 - Run configure before running a mach cargo command. r=firefox-build-system-reviewers,ahochheiden

When there is no configured environment, mach cargo commands always need
one. `BuildDriver.build` does create one, but for commands that don't
need that, we do need configure. Ideally, we wouldn't, but that requires
moving all the cargo invocation logic out of rust.mk, which would be
more work.

Differential Revision: https://phabricator.services.mozilla.com/D173109

python/mozbuild/mozbuild/mach_commands.py

@@ -236,11 +236,11 @@ def cargo(
     if cargo_extra_flags is not None:
         cargo_extra_flags = " ".join(cargo_extra_flags)
 
-    if cargo_build_flags:
-        try:
-            command_context.config_environment
-        except BuildEnvironmentNotFoundException:
-            build = command_context._spawn(BuildDriver)
+    try:
+        command_context.config_environment
+    except BuildEnvironmentNotFoundException:
+        build = command_context._spawn(BuildDriver)
+        if cargo_build_flags:
             ret = build.build(
                 command_context.metrics,
                 what=["pre-export", "export"],
@@ -248,8 +248,13 @@ def cargo(
                 verbose=verbose,
                 mach_context=command_context._mach_context,
             )
-            if ret != 0:
-                return ret
+        else:
+            ret = build.configure(
+                command_context.metrics,
+                buildstatus_messages=False,
+            )
+        if ret != 0:
+            return ret
 
     # XXX duplication with `mach vendor rust`
     crates_and_roots = {