remove Cylc 7 compatibility mode

changes.d/6849.break.md

@@ -0,0 +1 @@
+Cylc 7 compatibility mode has been removed, any workflows defined by a `suite.rc` file must now be upgraded to `flow.cylc` to run with the latest version of Cylc.

changes.d/6850.break.md

@@ -0,0 +1 @@
+The version of Jinja2 has been upgraded from 3.0 to 3.1, the version at which deprecated language features were removed.

cylc/flow/cfgspec/globalcfg.py

@@ -1418,10 +1418,6 @@ def default_for(
             desc=dedent('''
             Configuration defining a platform.
 
-            Many of these settings have replaced those of the same name from
-            the old Cylc 7 ``suite.rc[runtime][<namespace>][job]/[remote]``
-            and ``global.rc[hosts][<host>]`` sections.
-
             Platform names can be regular expressions: If you have a set of
             compute resources such as ``bigmachine1, bigmachine2`` or
             ``desktop0000, .., desktop9999`` one would define platforms with
@@ -1453,6 +1449,13 @@ def default_for(
                       [[localhost|cylc-server-..]]  # error
                       [[localhost, cylc-server-..]]  # ok
 
+            .. versionchanged:: 8.0.0
+
+                Many of these settings have replaced those of the same name
+                from the old Cylc 7
+                ``suite.rc[runtime][<namespace>][job]/[remote]``
+                and ``global.rc[hosts][<host>]`` sections.
+
             .. seealso::
 
                - :ref:`MajorChangesPlatforms` in the Cylc 8 migration guide.

cylc/flow/cfgspec/workflow.py

@@ -52,7 +52,6 @@
     TASK_EVENTS_SETTINGS,
     UTC_MODE_DESCR,
 )
-import cylc.flow.flags
 from cylc.flow.parsec.OrderedDict import OrderedDictWithDefaults
 from cylc.flow.parsec.config import (
     ConfigNode as Conf,
@@ -165,10 +164,8 @@ def get_script_common_text(this: str, example: Optional[str] = None):
 
         .. versionchanged:: 8.0.0
 
-           The configuration file was previously named ``suite.rc``, but that
-           name is now deprecated.
-           The ``suite.rc`` file name now activates :ref:`cylc_7_compat_mode`.
-           Rename to ``flow.cylc`` to turn off compatibility mode.
+           The configuration file was rename from ``suite.rc`` to
+           ``flow.cylc``.
     '''
 ) as SPEC:
 
@@ -2160,13 +2157,11 @@ def upg(
         '8.0.0',
         ['cylc', 'task event mail interval'],
         ['cylc', 'mail', 'task event batch interval'],
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
     u.deprecate(
         '8.0.0',
         ['runtime', '__MANY__', 'suite state polling'],
         ['runtime', '__MANY__', 'workflow state polling'],
-        silent=cylc.flow.flags.cylc7_back_compat,
         is_section=True,
     )
     u.obsolete(
@@ -2178,21 +2173,18 @@ def upg(
         '8.3.0',
         ['runtime', '__MANY__', 'workflow state polling', 'run-dir'],
         ['runtime', '__MANY__', 'workflow state polling', 'alt-cylc-run-dir'],
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
 
     u.deprecate(
         '8.0.0',
         ['cylc', 'parameters'],
         ['task parameters'],
-        silent=cylc.flow.flags.cylc7_back_compat,
         is_section=True,
     )
     u.deprecate(
         '8.0.0',
         ['cylc', 'parameter templates'],
         ['task parameters', 'templates'],
-        silent=cylc.flow.flags.cylc7_back_compat,
         is_section=True,
     )
     # Whole workflow task mail settings
@@ -2201,15 +2193,13 @@ def upg(
             '8.0.0',
             ['cylc', 'events', f'mail {mail_setting}'],
             ['cylc', 'mail', mail_setting],
-            silent=cylc.flow.flags.cylc7_back_compat,
         )
     # Task mail settings in [runtime][TASK]
     for mail_setting in ['to', 'from']:
         u.deprecate(
             '8.0.0',
             ['runtime', '__MANY__', 'events', f'mail {mail_setting}'],
             ['runtime', '__MANY__', 'mail', mail_setting],
-            silent=cylc.flow.flags.cylc7_back_compat,
         )
     u.deprecate(
         '8.0.0',
@@ -2219,7 +2209,6 @@ def upg(
             'DELETED (OBSOLETE) - use "global.cylc[scheduler][mail]smtp" '
             'instead')
         ),
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
     u.deprecate(
         '8.0.0',
@@ -2229,7 +2218,6 @@ def upg(
             'DELETED (OBSOLETE) - use "global.cylc[scheduler][mail]smtp" '
             'instead')
         ),
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
     u.deprecate(
         '8.0.0',
@@ -2239,13 +2227,11 @@ def upg(
             lambda x: f'P{int(x) - 1}' if x != '' else '',
             '"{old}" -> "{new}"'
         ),
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
     u.deprecate(
         '8.0.0',
         ['scheduling', 'hold after point'],
         ['scheduling', 'hold after cycle point'],
-        silent=cylc.flow.flags.cylc7_back_compat,
     )
 
     for job_setting in [
@@ -2259,7 +2245,6 @@ def upg(
             '8.0.0',
             ['runtime', '__MANY__', 'job', job_setting],
             ['runtime', '__MANY__', job_setting],
-            silent=cylc.flow.flags.cylc7_back_compat,
         )
 
     # Workflow timeout is now measured from start of run.
@@ -2280,7 +2265,6 @@ def upg(
             '8.0.0',
             ['cylc', 'events', old],
             ['cylc', 'events', new],
-            silent=cylc.flow.flags.cylc7_back_compat,
         )
 
     for old in [
@@ -2303,7 +2287,6 @@ def upg(
             '8.0.0',
             ['runtime', '__MANY__', 'events', old],
             ['runtime', '__MANY__', 'events', f"{old}s"],
-            silent=cylc.flow.flags.cylc7_back_compat,
         )
 
     for old in [
@@ -2320,7 +2303,6 @@ def upg(
         '8.0.0',
         ['cylc'],
         ['scheduler'],
-        silent=cylc.flow.flags.cylc7_back_compat,
         is_section=True,
     )
     u.upgrade()
@@ -2373,7 +2355,7 @@ def upgrade_graph_section(cfg: Dict[str, Any], descr: str) -> None:
                     elif key == 'graph' and isinstance(value, str):
                         graphdict[key] = value
                         keys.add(key)
-                if keys and not cylc.flow.flags.cylc7_back_compat:
+                if keys:
                     msg = (
                         'graph items were automatically upgraded '
                         f'in "{descr}":\n'
@@ -2395,14 +2377,13 @@ def upgrade_param_env_templates(cfg, descr):
         for task_name, task_items in cfg['runtime'].items():
             if 'parameter environment templates' not in task_items:
                 continue
-            if not cylc.flow.flags.cylc7_back_compat:
-                if first_warn:
-                    LOG.warning(upgrader.depr_msg)
-                    first_warn = False
-                LOG.warning(
-                    f' * (8.0.0) {dep % task_name} contents prepended to '
-                    f'{new % task_name}'
-                )
+            if first_warn:
+                LOG.warning(upgrader.depr_msg)
+                first_warn = False
+            LOG.warning(
+                f' * (8.0.0) {dep % task_name} contents prepended to '
+                f'{new % task_name}'
+            )
             for key, val in reversed(
                     task_items['parameter environment templates'].items()):
                 if 'environment' in task_items:
@@ -2432,7 +2413,7 @@ def warn_about_depr_platform(cfg):
             fail_if_platform_and_host_conflict(task_cfg, task_name)
             # Fail if backticks subshell e.g. platform = `foo`:
             is_platform_definition_subshell(task_cfg['platform'])
-        elif not cylc.flow.flags.cylc7_back_compat:
+        else:
             depr = get_platform_deprecated_settings(task_cfg, task_name)
             if depr:
                 msg = "\n".join(depr)
@@ -2445,7 +2426,7 @@ def warn_about_depr_platform(cfg):
 
 def warn_about_depr_event_handler_tmpl(cfg):
     """Warn if deprecated template strings appear in event handlers."""
-    if 'runtime' not in cfg or cylc.flow.flags.cylc7_back_compat:
+    if 'runtime' not in cfg:
         return
     deprecation_msg = (
         'The event handler template variable "%({0})s" is deprecated - '

cylc/flow/config.py

@@ -151,7 +151,6 @@
 from cylc.flow.workflow_files import (
     NO_TITLE,
     WorkflowFiles,
-    check_deprecation,
 )
 from cylc.flow.xtrigger_mgr import XtriggerCollator
 
@@ -295,7 +294,6 @@ def __init__(
                 See https://github.com/cylc/cylc-rose/issues/319
 
         """
-        check_deprecation(Path(fpath), force_compat_mode=force_compat_mode)
         self.mem_log = mem_log_func
         if self.mem_log is None:
             self.mem_log = lambda x: None
@@ -729,10 +727,7 @@ def process_cycle_point_tz(self):
         """
 
         cfg_cp_tz = self.cfg['scheduler'].get('cycle point time zone')
-        if (
-            not cylc.flow.flags.cylc7_back_compat
-            and not cfg_cp_tz
-        ):
+        if not cfg_cp_tz:
             cfg_cp_tz = 'Z'
         # Get the original workflow run time zone if restart:
         orig_cp_tz = getattr(self.options, 'cycle_point_tz', None)
@@ -953,17 +948,10 @@ def _check_implicit_tasks(self) -> None:
             raise WorkflowConfigError(msg)
         # Otherwise "[scheduler]allow implicit tasks" is not set
 
-        if not cylc.flow.flags.cylc7_back_compat:
-            msg += (
-                "\nTo allow implicit tasks, use "
-                f"'{WorkflowFiles.FLOW_FILE}[scheduler]allow implicit tasks'"
-            )
-        # Allow implicit tasks in back-compat mode unless rose-suite.conf
-        # present (to maintain compat with Rose 2019)
-        elif not (self.fpath.parent / "rose-suite.conf").is_file():
-            LOG.debug(msg)
-            return
-
+        msg += (
+            "\nTo allow implicit tasks, use "
+            f"'{WorkflowFiles.FLOW_FILE}[scheduler]allow implicit tasks'"
+        )
         raise WorkflowConfigError(msg)
 
     def _check_circular(self):
@@ -1118,13 +1106,6 @@ def _check_completion_expression(
                 Does this task have any suicide triggers
 
         """
-        # check completion expressions are not being used in compat mode
-        if cylc.flow.flags.cylc7_back_compat:
-            raise WorkflowConfigError(
-                '[runtime][<namespace>]completion cannot be used'
-                ' in Cylc 7 compatibility mode.'
-            )
-
         # check for invalid triggers in the expression
         if 'submit-failed' in expr:
             raise WorkflowConfigError(
@@ -2499,7 +2480,7 @@ def _proc_triggers(self, parser, seq, task_triggers):
                 if suicide:
                     suicides += 1
 
-        if suicides and not cylc.flow.flags.cylc7_back_compat:
+        if suicides:
             LOG.info(
                 f"{suicides} suicide trigger(s) detected. These are rarely "
                 "needed in Cylc 8 - see https://cylc.github.io/cylc-doc/"
@@ -2854,7 +2835,7 @@ def _upg_wflow_event_names(self) -> None:
                     event_names[i] = upgraded[event] = (
                         WorkflowEventHandler.EVENTS_DEPRECATED[event]
                     )
-            if upgraded and not cylc.flow.flags.cylc7_back_compat:
+            if upgraded:
                 LOG.warning(
                     f"{upgrader.depr_msg}\n"
                     f" * (8.0.0) [scheduler][events][{setting}] "

cylc/flow/flags.py

@@ -15,10 +15,14 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-"""Some global flags used in cylc"""
+"""Some global flags used in cylc.
+
+DEPRECATED:
+    We have been gradually whittling down the number of flags stored here.
+
+    Please do not add any further flags, to this module.
+
+"""
 
 # verbosity (<0=quiet, 0=normal, >0=verbose, >1=debug)
 verbosity: int = 0
-
-# Cylc 7 backward compatibility mode.
-cylc7_back_compat = False

cylc/flow/graph_parser.py

@@ -28,7 +28,6 @@
     Union
 )
 
-import cylc.flow.flags
 from cylc.flow.exceptions import GraphParseError
 from cylc.flow.param_expand import GraphExpander
 from cylc.flow.task_id import TaskID
@@ -816,11 +815,6 @@ def _set_output_opt(
             fam_member: is this from an expanded family trigger?
 
         """
-        if cylc.flow.flags.cylc7_back_compat:
-            # Set all outputs optional (set :succeed required elsewhere).
-            self.task_output_opt[(name, output)] = (True, True, True)
-            return
-
         # Do not infer output optionality from suicide triggers:
         if suicide:
             return
@@ -899,6 +893,9 @@ def _set_output_opt(
                 optional, default, oset = (
                     self.task_output_opt[(name, output)]
                 )
+
+                # NOTE: sort for stable error messages
+                output, opposite = sorted((output, opposite))
                 msg = (f"Opposite outputs {name}:{output} and {name}:"
                        f"{opposite} must both be optional if both are used")
                 if fam_member or not opp_fixed:

cylc/flow/install.py

@@ -60,7 +60,6 @@
 from cylc.flow.workflow_files import (
     WorkflowFiles,
     abort_if_flow_file_in_path,
-    check_deprecation,
     check_flow_file,
     get_cylc_run_abs_path,
     is_valid_run_dir,
@@ -346,7 +345,6 @@ def install_workflow(
             f"An error occurred when copying files from {source} to {rundir}")
         install_log.warning(f" Warning: {stderr}")
     cylc_install = Path(rundir.parent, WorkflowFiles.Install.DIRNAME)
-    check_deprecation(check_flow_file(rundir))
     if no_run_name:
         cylc_install = Path(rundir, WorkflowFiles.Install.DIRNAME)
     source_link = cylc_install.joinpath(WorkflowFiles.Install.SOURCE)
@@ -472,18 +470,24 @@ def link_runN(latest_run: Union[Path, str]):
 
 
 def validate_source_dir(
-    source: Union[Path, str], workflow_name: str
+    source: Union[Path, str],
+    workflow_name: str,
 ) -> None:
     """Ensure the source directory is valid:
         - has flow file
         - does not contain reserved dir names
 
     Args:
-        source: Path to source directory
+        source:
+            Path to source directory
+        workflow_name:
+            Workflow ID without the run identifier.
+
     Raises:
         WorkflowFilesError:
             If log, share, work or _cylc-install directories exist in the
             source directory.
+
     """
     # Source dir must not contain reserved run dir names (as file or dir).
     for dir_ in WorkflowFiles.RESERVED_DIRNAMES:
@@ -492,7 +496,7 @@ def validate_source_dir(
                 f"{workflow_name} installation failed "
                 f"- {dir_} exists in source directory."
             )
-    check_flow_file(source)
+    check_flow_file(source, allow_suite_rc=False)
 
 
 def parse_cli_sym_dirs(symlink_dirs: str) -> Dict[str, Dict[str, Any]]: