Fix non-parallel make under depfile jobserver (#32862)

When a package asks for non-parallel make, we need to force `make -j1` because just doing `make` will run in parallel under jobserver (e.g. `spack env depfile`).

We now always add `-j1` when asked for a non-parallel execution (even if there is no jobserver).

And each `MakeExecutable` can now ask for jobserver support or not. For example: the default `ninja` does not support jobserver so spack applies the default `-j`, but `ninja@kitware` or `ninja-fortran` does, so spack doesn't add `-j`.

Tips: you can run `SPACK_INSTALL_FLAGS=-j1 make -f spack-env-depfile.make -j8` to avoid massive job-spawning because of build tools that don't support jobserver (ninja).

3 files changed, 22 insertions, 5 deletions

diff --git a/var/spack/repos/builtin/packages/cmake/package.py b/var/spack/repos/builtin/packages/cmake/package.py
index e988af5ba2..0ce352b9ab 100644
--- a/var/spack/repos/builtin/packages/cmake/package.py
+++ b/var/spack/repos/builtin/packages/cmake/package.py
@@ -307,11 +307,20 @@ class Cmake(Package):
         args = []
         self.generator = make
 
+        if self.spec.satisfies("platform=windows"):
+            args.append("-GNinja")
+            self.generator = ninja
+
         if not sys.platform == "win32":
             args.append("--prefix={0}".format(self.prefix))
 
-            if spack.build_environment.should_set_parallel_jobs(jobserver_support=True):
-                args.append("--parallel={0}".format(make_jobs))
+            jobs = spack.build_environment.get_effective_jobs(
+                make_jobs,
+                parallel=self.parallel,
+                supports_jobserver=self.generator.supports_jobserver,
+            )
+            if jobs is not None:
+                args.append("--parallel={0}".format(jobs))
 
             if "+ownlibs" in spec:
                 # Build and link to the CMake-provided third-party libraries
@@ -338,9 +347,7 @@ class Cmake(Package):
             args.append("--")
         else:
             args.append("-DCMAKE_INSTALL_PREFIX=%s" % self.prefix)
-        if self.spec.satisfies("platform=windows"):
-            args.append("-GNinja")
-            self.generator = ninja
+
         args.append("-DCMAKE_BUILD_TYPE={0}".format(self.spec.variants["build_type"].value))
 
         # Install CMake correctly, even if `spack install` runs
diff --git a/var/spack/repos/builtin/packages/ninja-fortran/package.py b/var/spack/repos/builtin/packages/ninja-fortran/package.py
index 371b350add..4709f51694 100644
--- a/var/spack/repos/builtin/packages/ninja-fortran/package.py
+++ b/var/spack/repos/builtin/packages/ninja-fortran/package.py
@@ -86,3 +86,12 @@ class NinjaFortran(Package):
         # instead of 'ninja'. Install both for uniformity.
         with working_dir(prefix.bin):
             symlink("ninja", "ninja-build")
+
+    def setup_dependent_package(self, module, dspec):
+        name = "ninja"
+
+        module.ninja = MakeExecutable(
+            which_string(name, path=[self.spec.prefix.bin], required=True),
+            determine_number_of_jobs(parallel=self.parallel),
+            supports_jobserver=True,  # This fork supports jobserver
+        )
diff --git a/var/spack/repos/builtin/packages/ninja/package.py b/var/spack/repos/builtin/packages/ninja/package.py
index e71b648f26..a6ee815a2b 100644
--- a/var/spack/repos/builtin/packages/ninja/package.py
+++ b/var/spack/repos/builtin/packages/ninja/package.py
@@ -79,4 +79,5 @@ class Ninja(Package):
         module.ninja = MakeExecutable(
             which_string(name, path=[self.spec.prefix.bin], required=True),
             determine_number_of_jobs(parallel=self.parallel),
+            supports_jobserver=self.spec.version == ver("kitware"),
         )