Fix RedHat install of non-default fortran version.

The SCL version of sudo is broken, this disables that version that is first in the PATH so that the regular sudo is used.

https://bugzilla.redhat.com/show_bug.cgi?id=1319936

Adds a symlink from /usr/bin/gfortran-<version> to the SCL installed version.

PiperOrigin-RevId: 352897972

perfkitbenchmarker/linux_packages/fortran.py

@@ -51,6 +51,13 @@ def _YumInstallVersion(vm, version):
   vm.InstallPackages(f'{devtoolset}-gcc-gfortran')
   # Sets the path to use the newly installed version
   vm.RemoteCommand(f'echo "source scl_source enable {devtoolset}" >> .bashrc')
+  # SCL's sudo is broken, remove it to use the normal /bin/sudo
+  vm.RemoteCommand(f'sudo rm /opt/rh/{devtoolset}/root/usr/bin/sudo')
+  # Normally a gfortran-{version} symlink is installed, create one
+  sym_link = f'/usr/bin/gfortran-{version}'
+  real_path = f'/opt/rh/{devtoolset}/root/usr/bin/gfortran'
+  vm.RemoteCommand(
+      f'sudo alternatives --install {sym_link} fortran {real_path} 100')
 
 
 def _AptInstallVersion(vm, version):

tests/linux_packages/fortran_test.py

@@ -0,0 +1,67 @@
+# Lint as: python3
+"""Tests for Fortran package."""
+
+import unittest
+import mock
+from perfkitbenchmarker.linux_packages import fortran
+from tests import pkb_common_test_case
+
+
+def MockVm():
+  vm = mock.Mock()
+  # For the logging call
+  vm.RemoteCommand.return_value = 'fortran_version', ''
+  return vm
+
+
+class FortranRepoTestCase(pkb_common_test_case.PkbCommonTestCase):
+
+  def assertRemoteCommandsCalled(self, expected_calls, vm):
+    # call_args_list.assert.... hard to read
+    for command, call_arg_entry in zip(expected_calls,
+                                       vm.RemoteCommand.call_args_list):
+      self.assertEqual(command, call_arg_entry[0][0])
+    self.assertLen(vm.RemoteCommand.call_args_list, len(expected_calls))
+
+  def testAptInstall(self) -> None:
+    # test when no --fortran_version is passed in
+    vm = MockVm()
+    fortran.AptInstall(vm)
+    vm.InstallPackages.assert_called_with('gfortran')
+
+  def testYumInstall(self) -> None:
+    # test when no --fortran_version is passed in
+    vm = MockVm()
+    fortran.YumInstall(vm)
+    vm.InstallPackages.assert_called_with('gcc-gfortran libgfortran')
+
+  def testAptInstallVersion(self) -> None:
+    vm = MockVm()
+    fortran._AptInstallVersion(vm, 9)
+    vm.Install.assert_called_with('ubuntu_toolchain')
+    vm.InstallPackages.assert_called_with('gfortran-9')
+    expected_commands = [
+        'sudo update-alternatives --install /usr/bin/gfortran gfortran '
+        '/usr/bin/gfortran-9 100'
+    ]
+    self.assertRemoteCommandsCalled(expected_commands, vm)
+
+  def testYumInstallVersion(self) -> None:
+    vm = MockVm()
+    fortran._YumInstallVersion(vm, 9)
+    vm.InstallPackages.assert_has_calls([
+        mock.call('centos-release-scl-rh'),
+        mock.call('devtoolset-9-gcc-gfortran')
+    ])
+    scl_bin = '/opt/rh/devtoolset-9/root/usr/bin'
+    expected_commands = [
+        'echo "source scl_source enable devtoolset-9" >> .bashrc',
+        f'sudo rm {scl_bin}/sudo',
+        'sudo alternatives --install /usr/bin/gfortran-9 fortran '
+        f'{scl_bin}/gfortran 100'
+    ]
+    self.assertRemoteCommandsCalled(expected_commands, vm)
+
+
+if __name__ == '__main__':
+  unittest.main()