Bugfix: Compiler bootstrapping for compilers that are independently present in env (#32228)

The compiler bootstrapping logic currently does not add a task when the compiler package is already in the install task queue. This causes failures when the compiler package is added without the additional metadata telling the task to update the compilers list.

Solution: requeue compilers for bootstrapping when needed, to update `task.compiler` metadata.

lib/spack/spack/installer.py

@@ -803,8 +803,34 @@ def _add_bootstrap_compilers(self, compiler, architecture, pkgs, request, all_de
         """
         packages = _packages_needed_to_bootstrap_compiler(compiler, architecture, pkgs)
         for (comp_pkg, is_compiler) in packages:
-            if package_id(comp_pkg) not in self.build_tasks:
+            pkgid = package_id(comp_pkg)
+            if pkgid not in self.build_tasks:
                 self._add_init_task(comp_pkg, request, is_compiler, all_deps)
+            elif is_compiler:
+                # ensure it's queued as a compiler
+                self._modify_existing_task(pkgid, "compiler", True)
+
+    def _modify_existing_task(self, pkgid, attr, value):
+        """
+        Update a task in-place to modify its behavior.
+
+        Currently used to update the ``compiler`` field on tasks
+        that were originally created as a dependency of a compiler,
+        but are compilers in their own right.
+
+        For example, ``intel-oneapi-compilers-classic`` depends on
+        ``intel-oneapi-compilers``, which can cause the latter to be
+        queued first as a non-compiler, and only later as a compiler.
+        """
+        for i, tup in enumerate(self.build_pq):
+            key, task = tup
+            if task.pkg_id == pkgid:
+                tty.debug(
+                    "Modifying task for {0} to treat it as a compiler".format(pkgid),
+                    level=2,
+                )
+                setattr(task, attr, value)
+                self.build_pq[i] = (key, task)
 
     def _add_init_task(self, pkg, request, is_compiler, all_deps):
         """

lib/spack/spack/test/installer.py

@@ -467,6 +467,26 @@ def _conc_spec(compiler):
     assert packages
 
 
+def test_update_tasks_for_compiler_packages_as_compiler(mock_packages, config, monkeypatch):
+    spec = spack.spec.Spec("trivial-install-test-package").concretized()
+    installer = inst.PackageInstaller([(spec.package, {})])
+
+    # Add a task to the queue
+    installer._add_init_task(spec.package, installer.build_requests[0], False, {})
+
+    # monkeypatch to make the list of compilers be what we test
+    def fake_package_list(compiler, architecture, pkgs):
+        return [(spec.package, True)]
+
+    monkeypatch.setattr(inst, "_packages_needed_to_bootstrap_compiler", fake_package_list)
+
+    installer._add_bootstrap_compilers("fake", "fake", "fake", None, {})
+
+    # Check that the only task is now a compiler task
+    assert len(installer.build_pq) == 1
+    assert installer.build_pq[0][1].compiler
+
+
 def test_dump_packages_deps_ok(install_mockery, tmpdir, mock_packages):
     """Test happy path for dump_packages with dependencies."""