Implement limit on output errors

Ref. #748

rflx/cli.py

@@ -11,7 +11,7 @@
 from pkg_resources import get_distribution
 
 from rflx import __version__
-from rflx.error import RecordFluxError, Severity, Subsystem, fail
+from rflx.error import FAIL_AFTER_VALUE, RecordFluxError, Severity, Subsystem, fail
 from rflx.generator import Generator
 from rflx.graph import Graph
 from rflx.model import Message, Model, Session
@@ -28,6 +28,13 @@ def main(argv: List[str]) -> Union[int, str]:
         "-q", "--quiet", action="store_true", help="disable logging to standard output"
     )
     parser.add_argument("--version", action="store_true")
+    parser.add_argument(
+        "--max-errors",
+        type=int,
+        default=0,
+        metavar=("NUM"),
+        help="exit after at most NUM errors",
+    )
 
     subparsers = parser.add_subparsers(dest="subcommand")
 
@@ -42,8 +49,8 @@ def main(argv: List[str]) -> Union[int, str]:
         "-p",
         "--prefix",
         type=str,
-        default="RFLX",
-        help=("add prefix to generated packages " f"(default: {DEFAULT_PREFIX})"),
+        default=DEFAULT_PREFIX,
+        help="add prefix to generated packages (default: %(default)s)",
     )
     parser_generate.add_argument(
         "-n", "--no-library", help="omit generating library files", action="store_true"
@@ -99,6 +106,8 @@ def main(argv: List[str]) -> Union[int, str]:
     if args.quiet:
         logging.disable(logging.CRITICAL)
 
+    FAIL_AFTER_VALUE.v = args.max_errors
+
     try:
         args.func(args)
     except RecordFluxError as e:

rflx/error.py

@@ -2,10 +2,14 @@
 from collections import deque
 from enum import Enum, auto
 from pathlib import Path
+from threading import local
 from typing import Deque, List, NoReturn, Optional, Tuple, TypeVar, Union
 
 from rflx.common import Base, verbose_repr
 
+FAIL_AFTER_VALUE = local()
+FAIL_AFTER_VALUE.v = 0
+
 
 class Location(Base):
     def __init__(
@@ -138,21 +142,32 @@ def append(
         self, message: str, subsystem: Subsystem, severity: Severity, location: Location = None
     ) -> None:
         self.__errors.append(BaseError.Entry(message, subsystem, severity, location))
+        if get_fail_after() > 0 and len(self.__errors) >= get_fail_after():
+            raise self
 
     def appendleft(
         self, message: str, subsystem: Subsystem, severity: Severity, location: Location = None
     ) -> None:
         self.__errors.appendleft(BaseError.Entry(message, subsystem, severity, location))
+        if get_fail_after() > 0 and len(self.__errors) >= get_fail_after():
+            raise self
 
     def extend(
         self,
         entries: Union[List[Tuple[str, Subsystem, Severity, Optional[Location]]], "BaseError"],
     ) -> None:
+        # pylint: disable = global-statement
+        global FAIL_AFTER_VALUE
         if isinstance(entries, BaseError):
             self.__errors.extend(entries.errors)
         else:
             for message, subsystem, severity, location in entries:
                 self.__errors.append(BaseError.Entry(message, subsystem, severity, location))
+        num_errors = len(
+            list(e for e in self.__errors if e.severity in (Severity.WARNING, Severity.ERROR))
+        )
+        if 0 < FAIL_AFTER_VALUE.v <= num_errors:
+            raise self
 
     def check(self) -> bool:
         return len(self.__errors) > 0

tests/data/specs/multiple_errors.rflx

@@ -0,0 +1,12 @@
+package Multiple_Errors is
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+   type INVALID is mod 2**8;
+end Multiple_Errors;

tests/unit/cli_test.py

@@ -160,3 +160,22 @@ def test_main_unexpected_exception(monkeypatch: Any, tmp_path: Path) -> None:
         str(cli.main(["rflx", "generate", "-d", str(tmp_path), SPEC_FILE])),
         re.DOTALL,
     )
+
+
+def test_fail_fast() -> None:
+    assert (
+        len(
+            str(
+                cli.main(
+                    [
+                        "rflx",
+                        "--max-errors",
+                        "5",
+                        "check",
+                        str(SPEC_DIR / "multiple_errors.rflx"),
+                    ]
+                )
+            ).split("\n")
+        )
+        == 10
+    )