Update just in mode install and don't fail if mode check for tools.sy…

…stem.package_manager (#11712)

* update just if install

* review

* unused import

conan/tools/system/package_manager.py

@@ -132,16 +132,11 @@ def _install(self, packages, update=False, check=True, **kwargs):
                                         "installed".format(" ".join(packages)))
 
     def _update(self):
-        if self._mode == self.mode_check:
-            raise ConanException("Can't update because tools.system.package_manager:mode is '{0}'."
-                                 "Please update packages manually or set "
-                                 "'tools.system.package_manager:mode' "
-                                 "to '{1}' in the [conf] section of the profile, "
-                                 "or in the command line using "
-                                 "'-c tools.system.package_manager:mode={1}'".format(self.mode_check,
-                                                                                     self.mode_install))
-        command = self.update_command.format(sudo=self.sudo_str, tool=self.tool_name)
-        return self._conanfile_run(command, self.accepted_update_codes)
+        # we just update the package manager database in case we are in 'install mode'
+        # in case we are in check mode warn about that but don't fail
+        if self._mode == self.mode_install:
+            command = self.update_command.format(sudo=self.sudo_str, tool=self.tool_name)
+            return self._conanfile_run(command, self.accepted_update_codes)
 
     def _check(self, packages):
         missing = [pkg for pkg in packages if self.check_package(self.get_package_name(pkg)) != 0]

conans/test/integration/tools/system/package_manager_test.py

@@ -130,27 +130,8 @@ def fake_check(*args, **kwargs):
                                          "'-c tools.system.package_manager:mode=install'"
 
 
-@pytest.mark.parametrize("tool_class",
-                         [Apt, Yum, Dnf, Brew, Pkg, PkgUtil, Chocolatey, PacMan, Zypper])
-def test_tools_update_mode_check(tool_class):
-    conanfile = ConanFileMock()
-    conanfile.conf = Conf()
-    conanfile.settings = Settings()
-    conanfile.conf["tools.system.package_manager:tool"] = tool_class.tool_name
-    conanfile.conf["tools.system.package_manager:mode"] = "check"
-    with mock.patch('conans.ConanFile.context', new_callable=PropertyMock) as context_mock:
-        context_mock.return_value = "host"
-        tool = tool_class(conanfile)
-        with pytest.raises(ConanException) as exc_info:
-            tool.update()
-        assert exc_info.value.args[0] == "Can't update because tools.system.package_manager:mode is " \
-                                         "'check'.Please update packages manually or set " \
-                                         "'tools.system.package_manager:mode' to 'install' in the [conf] " \
-                                         "section of the profile, or in the command line using " \
-                                         "'-c tools.system.package_manager:mode=install'"
-
-
-@pytest.mark.parametrize("tool_class, result", [
+@pytest.mark.parametrize("tool_class, result",
+[
     (Apt, "apt-get update"),
     (Yum, "yum check-update -y"),
     (Dnf, "dnf check-update -y"),
@@ -166,12 +147,17 @@ def test_tools_update_mode_install(tool_class, result):
     conanfile.conf = Conf()
     conanfile.settings = Settings()
     conanfile.conf["tools.system.package_manager:tool"] = tool_class.tool_name
-    conanfile.conf["tools.system.package_manager:mode"] = "install"
-    with mock.patch('conans.ConanFile.context', new_callable=PropertyMock) as context_mock:
-        context_mock.return_value = "host"
-        tool = tool_class(conanfile)
-        tool.update()
-    assert tool._conanfile.command == result
+    for mode in ["check", "install"]:
+        conanfile.conf["tools.system.package_manager:mode"] = mode
+        with mock.patch('conans.ConanFile.context', new_callable=PropertyMock) as context_mock:
+            context_mock.return_value = "host"
+            tool = tool_class(conanfile)
+            tool.update()
+            if mode == "install":
+                assert tool._conanfile.command == result
+            else:
+                # does not run the update when mode check
+                assert tool._conanfile.command == None
 
 
 @pytest.mark.parametrize("tool_class, result", [