[Pather/Planner] Improve error reporting

masque/__init__.py

@@ -82,6 +82,8 @@ from .abstract import Abstract as Abstract
 from .builder import (
     Tool as Tool,
     Pather as Pather,
+    RouteError as RouteError,
+    RouteFailureDetails as RouteFailureDetails,
     RenderStep as RenderStep,
     AutoTool as AutoTool,
     PathTool as PathTool,

masque/builder/__init__.py

@@ -41,6 +41,11 @@ from .pather import (
     Pather as Pather,
     PortPather as PortPather,
 )
+from .error import (
+    RouteError as RouteError,
+    RouteFailureDetails as RouteFailureDetails,
+    RouteOperation as RouteOperation,
+)
 from .utils import ell as ell
 from .tools import (
     Tool as Tool,

masque/builder/error.py

@@ -0,0 +1,65 @@
+"""Public routing failure diagnostics."""
+from typing import Any, Literal
+from collections.abc import Mapping
+from dataclasses import dataclass
+from pprint import pformat
+from types import MappingProxyType
+
+from ..error import BuildError
+
+
+RouteOperation = Literal['trace', 'trace_to', 'jog', 'uturn']
+
+
+@dataclass(frozen=True, slots=True)
+class RouteFailureDetails:
+    """Structured context for a failed Pather routing request."""
+
+    operation: RouteOperation
+    portspec: str
+    in_ptype: str | None
+    out_ptype: str | None
+    request: Mapping[str, Any]
+    resolved_length: float | None
+    resolved_jog: float | None
+    minimum_length: float | None
+    minimum_attempted: bool
+    minimum_exhausted: bool
+    cause: str
+    minimum_cause: str | None = None
+
+    def __post_init__(self) -> None:
+        object.__setattr__(self, 'request', MappingProxyType(dict(self.request)))
+
+
+class RouteError(BuildError):
+    """A route-selection failure with structured request diagnostics."""
+
+    details: RouteFailureDetails
+    fatal: bool
+
+    def __init__(self, details: RouteFailureDetails, *, fatal: bool = False) -> None:
+        self.details = details
+        self.fatal = fatal
+        if not details.minimum_attempted:
+            minimum = 'not evaluated'
+        elif details.minimum_length is not None:
+            minimum = f'{details.minimum_length:g}'
+        elif details.minimum_exhausted:
+            minimum = 'unavailable (no legal route exists at any length)'
+        else:
+            minimum = 'unavailable (minimum-length calculation failed)'
+
+        lines = [
+            f'Unable to plan {details.operation} route for port {details.portspec!r}:',
+            f'  in_ptype: {details.in_ptype!r}',
+            f'  out_ptype: {details.out_ptype!r}',
+            f'  request: {pformat(dict(details.request), compact=True)}',
+            f'  resolved_length: {details.resolved_length!r}',
+            f'  resolved_jog: {details.resolved_jog!r}',
+            f'  preferred_minimum_length: {minimum}',
+            f'  cause: {details.cause}',
+            ]
+        if details.minimum_cause is not None:
+            lines.append(f'  minimum_failure: {details.minimum_cause}')
+        super().__init__('\n'.join(lines))

masque/builder/planner/planner.py

@@ -22,7 +22,7 @@ from __future__ import annotations
 # ruff: noqa: ANN401,PLR0912,PLR0913,PLR0915,TC001,TC002,TC003
 
 from collections.abc import Iterable, Mapping, Sequence
-from dataclasses import dataclass
+from dataclasses import dataclass, replace
 from itertools import combinations
 from math import cos, isclose as math_isclose, sin
 from typing import Any, Literal
@@ -43,6 +43,7 @@ from ..tools import (
     StraightOffer,
     Tool,
     )
+from ..error import RouteError, RouteFailureDetails, RouteOperation
 from ..utils import ell
 from . import bounds as planner_bounds
 from .interface import (
@@ -56,6 +57,10 @@ from .interface import (
 RouteTieBreakStrategy = Literal['straight_first', 'turn_first']
 
 
+class NoLegalRouteError(BuildError):
+    """Internal marker for exhaustive candidate-selection failure."""
+
+
 def validate_strategy(strategy: RouteTieBreakStrategy | str) -> RouteTieBreakStrategy:
     """Return a supported route tie-break strategy or raise a routing error."""
     if strategy in ('straight_first', 'turn_first'):
@@ -396,9 +401,11 @@ class Solver:
             if errors:
                 last_error = errors[-1]
                 if self.request.route_name in str(last_error):
-                    raise last_error
+                    raise NoLegalRouteError(str(last_error)) from last_error
-                raise BuildError(f'{self.request.route_name} route is unsupported: {last_error}') from last_error
+                raise NoLegalRouteError(
-            raise BuildError(f'No legal primitive offer for {self.request.route_name}')
+                    f'{self.request.route_name} route is unsupported: {last_error}'
+                    ) from last_error
+            raise NoLegalRouteError(f'No legal primitive offer for {self.request.route_name}')
 
         return min(
             candidates,
@@ -1038,6 +1045,9 @@ class RoutingPlanner:
             self,
             family: PrimitiveKind,
             context: RoutePortContext,
+            operation: RouteOperation | None = None,
+            diagnostic_request: Mapping[str, Any] | None = None,
+            /,
             *,
             length: float | None = None,
             jog: float | None = None,
@@ -1049,6 +1059,32 @@ class RoutingPlanner:
             **kwargs: Any,
             ) -> RouteLeg:
         """Solve one route leg and attach it to its source Pather context."""
+        if operation is None:
+            if family in ('straight', 'bend'):
+                operation = 'trace'
+            elif family == 's':
+                operation = 'jog'
+            else:
+                operation = 'uturn'
+        if diagnostic_request is None:
+            diagnostic_request = {}
+
+        if length is not None and (not numpy.isfinite(length) or length < 0):
+            details = RouteFailureDetails(
+                operation=operation,
+                portspec=context.portspec,
+                in_ptype=context.port.ptype,
+                out_ptype=kwargs.get('out_ptype'),
+                request=diagnostic_request,
+                resolved_length=float(length),
+                resolved_jog=None if jog is None else float(jog),
+                minimum_length=None,
+                minimum_attempted=False,
+                minimum_exhausted=False,
+                cause='Resolved route length must be finite and nonnegative',
+                )
+            raise RouteError(details, fatal=True)
+
         request = self.route_request(
             family=family,
             context=context,
@@ -1062,10 +1098,47 @@ class RoutingPlanner:
             )
         try:
             candidate = self.solver_for_request(request).solve()
-        except BuildError as err:
+        except NoLegalRouteError as err:
-            if family == 'u' and length is None and not getattr(err, 'fatal', False):
+            cause = (
-                raise BuildError('No legal primitive offer for omitted-length U-turn') from err
+                'No legal primitive offer for omitted-length U-turn'
-            raise
+                if family == 'u' and length is None
+                else str(err)
+                )
+
+            minimum_length: float | None = None
+            minimum_cause: str | None = None
+            minimum_exhausted = False
+            if length is None:
+                minimum_cause = cause
+                minimum_exhausted = True
+            else:
+                minimum_request = replace(request, length=None)
+                try:
+                    minimum_candidate = self.solver_for_request(minimum_request).solve()
+                    minimum_length = minimum_candidate.public_length
+                except NoLegalRouteError as minimum_err:
+                    minimum_cause = str(minimum_err)
+                    minimum_exhausted = True
+                except Exception as minimum_err:
+                    if route_error_is_fatal(minimum_err):
+                        raise
+                    minimum_cause = str(minimum_err)
+
+            details = RouteFailureDetails(
+                operation=operation,
+                portspec=context.portspec,
+                in_ptype=context.port.ptype,
+                out_ptype=request.out_ptype,
+                request=diagnostic_request,
+                resolved_length=None if length is None else float(length),
+                resolved_jog=None if jog is None else float(jog),
+                minimum_length=minimum_length,
+                minimum_attempted=True,
+                minimum_exhausted=minimum_exhausted,
+                cause=cause,
+                minimum_cause=minimum_cause,
+                )
+            raise RouteError(details) from err
         return self.route_leg_from_candidate(context, candidate, plug_into=plug_into)
 
     def prepared_route_action_from_leg(
@@ -1129,25 +1202,87 @@ class RoutingPlanner:
             ) -> PreparedRouteResult:
         """Plan straight or single-bend traces, including `each` and bundle-bound modes."""
         route_bounds = dict(bounds)
+        request_details = {'ccw': ccw, **{
+            key: value for key, value in route_bounds.items() if value is not None
+            }}
+        if length is not None:
+            request_details['length'] = length
+        if spacing is not None:
+            request_details['spacing'] = spacing
+        if strategy is not None:
+            request_details['strategy'] = strategy
+        operation: RouteOperation = 'trace'
+        diagnostic_request = request_details
+        return self._plan_trace_route(
+            contexts,
+            ccw,
+            length,
+            operation,
+            diagnostic_request,
+            spacing=spacing,
+            strategy=strategy,
+            **route_bounds,
+            )
+
+    def _plan_trace_route(
+            self,
+            contexts: Sequence[RoutePortContext],
+            ccw: SupportsBool | None,
+            length: float | None,
+            operation: RouteOperation,
+            diagnostic_request: Mapping[str, Any],
+            /,
+            *,
+            spacing: float | ArrayLike | None,
+            strategy: RouteTieBreakStrategy | str | None,
+            **route_bounds: Any,
+            ) -> PreparedRouteResult:
         portspec = tuple(context.portspec for context in contexts)
         planner_bounds.validate_trace_args(portspec, length=length, spacing=spacing, bounds=route_bounds)
         family: Literal['straight', 'bend'] = 'straight' if ccw is None else 'bend'
         if length is not None:
-            leg = self.plan_leg(family, contexts[0], length=length, ccw=ccw, strategy=strategy, **route_bounds)
+            leg = self.plan_leg(
+                family,
+                contexts[0],
+                operation,
+                diagnostic_request,
+                length=length,
+                ccw=ccw,
+                strategy=strategy,
+                **route_bounds,
+                )
             return self.prepared_result_from_legs((leg,))
 
         if route_bounds.get('each') is not None:
             each = route_bounds.pop('each')
             return PreparedRouteResult(tuple(
                 self.prepared_route_action_from_leg(
-                    self.plan_leg(family, context, length=each, ccw=ccw, strategy=strategy, **route_bounds),
+                    self.plan_leg(
+                        family,
+                        context,
+                        operation,
+                        diagnostic_request,
+                        length=each,
+                        ccw=ccw,
+                        strategy=strategy,
+                        **route_bounds,
+                        ),
                     )
                 for context in contexts
                 ))
 
         bundle_bounds = planner_bounds.present_bundle_bounds(route_bounds)
         if not bundle_bounds:
-            leg = self.plan_leg(family, contexts[0], length=None, ccw=ccw, strategy=strategy, **route_bounds)
+            leg = self.plan_leg(
+                family,
+                contexts[0],
+                operation,
+                diagnostic_request,
+                length=None,
+                ccw=ccw,
+                strategy=strategy,
+                **route_bounds,
+                )
             return self.prepared_result_from_legs((leg,))
 
         bound_type = bundle_bounds[0]
@@ -1164,7 +1299,16 @@ class RoutingPlanner:
         actions = []
         for port_name, route_length in extensions.items():
             context = next(context for context in contexts if context.portspec == port_name)
-            leg = self.plan_leg(family, context, length=route_length, ccw=ccw, strategy=strategy, **route_bounds)
+            leg = self.plan_leg(
+                family,
+                context,
+                operation,
+                diagnostic_request,
+                length=route_length,
+                ccw=ccw,
+                strategy=strategy,
+                **route_bounds,
+                )
             actions.append(self.prepared_route_action_from_leg(leg))
         return PreparedRouteResult(tuple(actions))
 
@@ -1179,6 +1323,37 @@ class RoutingPlanner:
             ) -> PreparedRouteResult:
         """Plan `trace_to()` by resolving positional targets or delegating to `trace()` modes."""
         route_bounds = dict(bounds)
+        request_details = {'ccw': ccw, **{
+            key: value for key, value in route_bounds.items() if value is not None
+            }}
+        if spacing is not None:
+            request_details['spacing'] = spacing
+        if strategy is not None:
+            request_details['strategy'] = strategy
+        operation: RouteOperation = 'trace_to'
+        diagnostic_request = request_details
+        return self._plan_trace_to_route(
+            contexts,
+            ccw,
+            operation,
+            diagnostic_request,
+            spacing=spacing,
+            strategy=strategy,
+            **route_bounds,
+            )
+
+    def _plan_trace_to_route(
+            self,
+            contexts: Sequence[RoutePortContext],
+            ccw: SupportsBool | None,
+            operation: RouteOperation,
+            diagnostic_request: Mapping[str, Any],
+            /,
+            *,
+            spacing: float | ArrayLike | None,
+            strategy: RouteTieBreakStrategy | str | None,
+            **route_bounds: Any,
+            ) -> PreparedRouteResult:
         if len(contexts) == 1:
             resolved = planner_bounds.resolved_position_bound(contexts[0].port, route_bounds, allow_length=False)
         else:
@@ -1186,7 +1361,16 @@ class RoutingPlanner:
             if any(route_bounds.get(key) is not None for key in planner_bounds.POSITION_KEYS):
                 raise BuildError('Position bounds only allowed with a single port')
         if resolved is None:
-            return self.plan_trace_route(contexts, ccw, spacing=spacing, strategy=strategy, **route_bounds)
+            return self._plan_trace_route(
+                contexts,
+                ccw,
+                route_bounds.pop('length', None),
+                operation,
+                diagnostic_request,
+                spacing=spacing,
+                strategy=strategy,
+                **route_bounds,
+                )
 
         planner_bounds.validate_trace_to_positional_args(spacing=spacing, bounds=route_bounds)
         _key, _value, length = resolved
@@ -1196,7 +1380,16 @@ class RoutingPlanner:
             if key not in planner_bounds.POSITION_KEYS and key != 'length'
         }
         family: Literal['straight', 'bend'] = 'straight' if ccw is None else 'bend'
-        leg = self.plan_leg(family, contexts[0], length=length, ccw=ccw, strategy=strategy, **other_bounds)
+        leg = self.plan_leg(
+            family,
+            contexts[0],
+            operation,
+            diagnostic_request,
+            length=length,
+            ccw=ccw,
+            strategy=strategy,
+            **other_bounds,
+            )
         return self.prepared_result_from_legs((leg,))
 
     def plan_jog_route(
@@ -1210,8 +1403,28 @@ class RoutingPlanner:
             **bounds: Any,
             ) -> PreparedRouteResult:
         """Plan S-bend routes for single ports or spaced bundles."""
+        request_details = {'offset': offset, **{
+            key: value for key, value in bounds.items() if value is not None
+            }}
+        if length is not None:
+            request_details['length'] = length
+        if spacing is not None:
+            request_details['spacing'] = spacing
+        if strategy is not None:
+            request_details['strategy'] = strategy
+        operation: RouteOperation = 'jog'
+        diagnostic_request = request_details
         if numpy.isclose(offset, 0):
-            return self.plan_trace_to_route(contexts, None, length=length, spacing=spacing, strategy=strategy, **bounds)
+            return self._plan_trace_to_route(
+                contexts,
+                None,
+                operation,
+                diagnostic_request,
+                length=length,
+                spacing=spacing,
+                strategy=strategy,
+                **bounds,
+                )
         route_bounds = dict(bounds)
         portspec = tuple(context.portspec for context in contexts)
         planner_bounds.validate_jog_args(portspec, length=length, spacing=spacing, bounds=route_bounds)
@@ -1224,9 +1437,28 @@ class RoutingPlanner:
         if len(contexts) > 1:
             return PreparedRouteResult(tuple(
                 self.prepared_route_action_from_leg(leg)
-                for leg in self.plan_su_bundle_routes('s', contexts, offset, length, spacing, strategy=strategy, **other_bounds)
+                for leg in self.plan_su_bundle_routes(
+                    's',
+                    contexts,
+                    offset,
+                    length,
+                    spacing,
+                    operation,
+                    diagnostic_request,
+                    strategy=strategy,
+                    **other_bounds,
+                    )
                 ))
-        leg = self.plan_leg('s', contexts[0], length=length, jog=offset, strategy=strategy, **other_bounds)
+        leg = self.plan_leg(
+            's',
+            contexts[0],
+            operation,
+            diagnostic_request,
+            length=length,
+            jog=offset,
+            strategy=strategy,
+            **other_bounds,
+            )
         return self.prepared_result_from_legs((leg,))
 
     def plan_uturn_route(
@@ -1241,14 +1473,44 @@ class RoutingPlanner:
             ) -> PreparedRouteResult:
         """Plan U-turn routes for single ports or spaced bundles."""
         route_bounds = dict(bounds)
+        request_details = {'offset': offset, **{
+            key: value for key, value in route_bounds.items() if value is not None
+            }}
+        if length is not None:
+            request_details['length'] = length
+        if spacing is not None:
+            request_details['spacing'] = spacing
+        if strategy is not None:
+            request_details['strategy'] = strategy
+        operation: RouteOperation = 'uturn'
+        diagnostic_request = request_details
         portspec = tuple(context.portspec for context in contexts)
         planner_bounds.validate_uturn_args(portspec, spacing=spacing, bounds=route_bounds)
         if len(contexts) > 1:
             return PreparedRouteResult(tuple(
                 self.prepared_route_action_from_leg(leg)
-                for leg in self.plan_su_bundle_routes('u', contexts, offset, length, spacing, strategy=strategy, **route_bounds)
+                for leg in self.plan_su_bundle_routes(
+                    'u',
+                    contexts,
+                    offset,
+                    length,
+                    spacing,
+                    operation,
+                    diagnostic_request,
+                    strategy=strategy,
+                    **route_bounds,
+                    )
                 ))
-        leg = self.plan_leg('u', contexts[0], length=length, jog=offset, strategy=strategy, **route_bounds)
+        leg = self.plan_leg(
+            'u',
+            contexts[0],
+            operation,
+            diagnostic_request,
+            length=length,
+            jog=offset,
+            strategy=strategy,
+            **route_bounds,
+            )
         return self.prepared_result_from_legs((leg,))
 
     def plan_su_bundle_routes(
@@ -1258,6 +1520,9 @@ class RoutingPlanner:
             offset: float,
             length: float | None,
             spacing: float | ArrayLike | None,
+            operation: RouteOperation,
+            diagnostic_request: Mapping[str, Any],
+            /,
             *,
             strategy: RouteTieBreakStrategy | str | None = None,
             **kwargs: Any,
@@ -1270,14 +1535,32 @@ class RoutingPlanner:
         and offset so all legs can be planned independently.
         """
         if len(contexts) == 1:
-            return (self.plan_leg(kind, contexts[0], length=length, jog=offset, strategy=strategy, **kwargs),)
+            return (self.plan_leg(
+                kind,
+                contexts[0],
+                operation,
+                diagnostic_request,
+                length=length,
+                jog=offset,
+                strategy=strategy,
+                **kwargs,
+                ),)
         route_name = 'jog' if kind == 's' else 'uturn'
         if kind == 'u' and is_close(offset, 0):
             raise BuildError('multi-port uturn() requires nonzero offset to determine bundle ordering')
         contexts_by_name = {context.portspec: context for context in contexts}
         initial_specs = planner_bounds.su_bundle_specs(contexts, offset, 0, spacing, route_name=route_name)
         anchor_portspec, _anchor_length, _anchor_offset = initial_specs[0]
-        anchor = self.plan_leg(kind, contexts_by_name[anchor_portspec], length=length, jog=offset, strategy=strategy, **kwargs)
+        anchor = self.plan_leg(
+            kind,
+            contexts_by_name[anchor_portspec],
+            operation,
+            diagnostic_request,
+            length=length,
+            jog=offset,
+            strategy=strategy,
+            **kwargs,
+            )
         base_length = anchor.candidate.public_length
         specs = planner_bounds.su_bundle_specs(contexts, offset, base_length, spacing, route_name=route_name)
         first_portspec, _first_length, _first_offset = specs[0]
@@ -1287,7 +1570,10 @@ class RoutingPlanner:
                 routes_by_name[spec_portspec] = self.plan_leg(
                     'straight',
                     contexts_by_name[spec_portspec],
+                    operation,
+                    diagnostic_request,
                     length=spec_length,
+                    jog=spec_offset,
                     strategy=strategy,
                     **kwargs,
                     )
@@ -1295,6 +1581,8 @@ class RoutingPlanner:
                 routes_by_name[spec_portspec] = self.plan_leg(
                     kind,
                     contexts_by_name[spec_portspec],
+                    operation,
+                    diagnostic_request,
                     length=spec_length,
                     jog=spec_offset,
                     strategy=strategy,

masque/builder/utils.py

@@ -1,5 +1,5 @@
-from typing import SupportsFloat, cast, TYPE_CHECKING
+from typing import TYPE_CHECKING
-from collections.abc import Mapping, Sequence
+from collections.abc import Mapping
 from pprint import pformat
 
 import numpy
@@ -13,6 +13,17 @@ if TYPE_CHECKING:
     from ..ports import Port
 
 
+_EXTENSION_BOUND_TYPES = (
+    'emin', 'min_extension',
+    'emax', 'max_extension',
+    'min_past_furthest',
+    )
+_POSITION_MIN_BOUND_TYPES = ('pmin', 'min_position', 'xmin', 'ymin')
+_POSITION_MAX_BOUND_TYPES = ('pmax', 'max_position', 'xmax', 'ymax')
+_POSITION_BOUND_TYPES = _POSITION_MIN_BOUND_TYPES + _POSITION_MAX_BOUND_TYPES
+_BOUND_TYPES = _EXTENSION_BOUND_TYPES + _POSITION_BOUND_TYPES
+
+
 def ell(
         ports: Mapping[str, 'Port'],
         ccw: SupportsBool | None,
@@ -82,6 +93,18 @@ def ell(
     """
     if not ports:
         raise BuildError('Empty port list passed to `ell()`')
+    if bound_type not in _BOUND_TYPES:
+        raise BuildError(f'Invalid bound type {bound_type!r}; expected one of {_BOUND_TYPES}')
+
+    try:
+        bound_arr = numpy.asarray(bound, dtype=float)
+    except (TypeError, ValueError) as err:
+        raise BuildError('bound must be a numeric scalar or length-2 vector') from err
+    if bound_arr.size not in (1, 2):
+        raise BuildError(f'bound must be scalar or have length 2; got {bound_arr.size} values')
+    if not numpy.all(numpy.isfinite(bound_arr)):
+        raise BuildError('bound must contain only finite values')
+    bound_values = bound_arr.reshape(-1)
 
     if ccw is None:
         if spacing is not None and not numpy.allclose(spacing, 0):
@@ -173,38 +196,34 @@ def ell(
         travel = d_to_align - (ch_offsets.max() - ch_offsets)
         offsets = travel - travel.min().clip(max=0)
 
-    rot_bound: SupportsFloat
+    if bound_type in _EXTENSION_BOUND_TYPES:
-    if bound_type in ('emin', 'min_extension',
+        if numpy.any(bound_values < 0):
-                      'emax', 'max_extension',
+            raise BuildError(f'Got negative bound for extension: {bound_values}')
-                      'min_past_furthest',):
-        if numpy.size(bound) == 2:
-            bound = cast('Sequence[float]', bound)
-            rot_bound = (rot_matrix @ ((bound[0], 0),
-                                       (0, bound[1])))[0, :]
-        else:
-            bound = cast('float', bound)
-            rot_bound = numpy.array(bound)
 
-        if rot_bound < 0:
+        if bound_values.size == 2:
-            raise BuildError(f'Got negative bound for extension: {rot_bound}')
+            horizontal_weight = abs(float(numpy.cos(direction)))
+            vertical_weight = abs(float(numpy.sin(direction)))
+            use_x = horizontal_weight > vertical_weight or numpy.isclose(horizontal_weight, vertical_weight)
+            rot_bound = float(bound_values[0 if use_x else 1])
+        else:
+            rot_bound = float(bound_values[0])
 
         if bound_type in ('emin', 'min_extension', 'min_past_furthest'):
-            offsets += rot_bound.max()
+            offsets += rot_bound
         elif bound_type in ('emax', 'max_extension'):
-            offsets += rot_bound.min() - offsets.max()
+            offsets += rot_bound - offsets.max()
     else:
-        if numpy.size(bound) == 2:
+        if bound_values.size == 2:
-            bound = cast('Sequence[float]', bound)
+            rot_bound = float((rot_matrix @ bound_values)[0])
-            rot_bound = (rot_matrix @ bound)[0]
         else:
-            bound = cast('float', bound)
             neg = (direction + pi / 4) % (2 * pi) > pi
-            rot_bound = -bound if neg else bound
+            bound_scalar = float(bound_values[0])
+            rot_bound = -bound_scalar if neg else bound_scalar
 
         min_possible = x_start + offsets
-        if bound_type in ('pmax', 'max_position', 'xmax', 'ymax'):
+        if bound_type in _POSITION_MAX_BOUND_TYPES:
             extension = rot_bound - min_possible.max()
-        elif bound_type in ('pmin', 'min_position', 'xmin', 'ymin'):
+        else:
             extension = rot_bound - min_possible.min()
 
         offsets += extension

masque/test/test_builder.py

@@ -14,11 +14,17 @@ from ..ports import Port
 def test_builder_public_imports() -> None:
     from masque import PortPather as TopPortPather
     from masque import RenderStep as TopRenderStep
+    from masque import RouteError as TopRouteError
+    from masque import RouteFailureDetails as TopRouteFailureDetails
     from masque.builder import PortPather as BuilderPortPather
     from masque.builder import RenderStep as BuilderRenderStep
+    from masque.builder import RouteError as BuilderRouteError
+    from masque.builder import RouteFailureDetails as BuilderRouteFailureDetails
 
     assert TopPortPather is BuilderPortPather
     assert TopRenderStep is BuilderRenderStep
+    assert TopRouteError is BuilderRouteError
+    assert TopRouteFailureDetails is BuilderRouteFailureDetails
 
 
 def test_builder_init() -> None:
@@ -171,3 +177,41 @@ def test_ell_handles_array_spacing_when_ccw_none() -> None:
 
     with pytest.raises(BuildError, match='Spacing must be 0 or None'):
         ell(ports, None, 'min_extension', 5, spacing=numpy.array([1, 0]))
+
+
+@pytest.mark.parametrize('bound_type', ['emin', 'emax', 'min_past_furthest'])
+@pytest.mark.parametrize(
+    ('rotation', 'expected'),
+    [
+        (0, 5),
+        (pi / 2, 7),
+        (pi / 6, 5),
+        (pi / 3, 7),
+        (pi / 4, 5),
+    ],
+    )
+def test_ell_extension_vector_selects_dominant_route_axis(
+        bound_type: str,
+        rotation: float,
+        expected: float,
+        ) -> None:
+    result = ell({'A': Port((0, 0), rotation)}, None, bound_type, (5, 7), spacing=0)
+
+    assert_allclose(result['A'], expected)
+
+
+@pytest.mark.parametrize('bound', [(-1, 2), (1, -2), (numpy.nan, 2), (1, numpy.inf), (1, 2, 3)])
+def test_ell_rejects_invalid_extension_vector(bound: tuple[float, ...]) -> None:
+    with pytest.raises(BuildError, match='bound|negative'):
+        ell({'A': Port((0, 0), 0)}, None, 'emin', bound, spacing=0)
+
+
+def test_ell_position_vector_still_projects_onto_route_direction() -> None:
+    result = ell({'A': Port((0, 0), pi)}, None, 'pmax', (5, 7), spacing=0)
+
+    assert_allclose(result['A'], 5)
+
+
+def test_ell_rejects_invalid_bound_type() -> None:
+    with pytest.raises(BuildError, match='Invalid bound type'):
+        ell({'A': Port((0, 0), 0)}, None, 'nearest', 5, spacing=0)

masque/test/test_pather_constraints.py

@@ -5,9 +5,9 @@ import pytest
 import numpy
 from numpy import pi
 
-from masque import Pather, Library, Port
+from masque import Pather, Library, Port, RouteError
 from masque.builder.planner import RoutePortContext, RoutingPlanner
-from masque.builder.tools import BendOffer, PathTool, RenderStep, StraightOffer, Tool
+from masque.builder.tools import BendOffer, PathTool, RenderStep, StraightOffer, Tool, UOffer
 from masque.error import BuildError
 from masque.library import ILibrary
 
@@ -114,15 +114,306 @@ class CountingPathTool(PathTool):
         return super().render(batch, port_names=port_names, **kwargs)
 
 
+class RequestCountingTool(PlanningOnlyTool):
+    def __init__(self) -> None:
+        self.offer_calls = 0
+
+    def primitive_offers(
+            self,
+            kind: Literal['straight', 'bend', 's', 'u'],
+            *,
+            in_ptype: str | None = None,
+            out_ptype: str | None = None,
+            **kwargs: Any,
+            ) -> tuple[Any, ...]:
+        self.offer_calls += 1
+        return super().primitive_offers(
+            kind,
+            in_ptype=in_ptype,
+            out_ptype=out_ptype,
+            **kwargs,
+            )
+
+
+class PreferredMinimumTool(PlanningOnlyTool):
+    def __init__(self) -> None:
+        self.commit_calls = 0
+        self.diagnostic_context_kwargs: list[Any] = []
+
+    def _commit(self, parameter: float) -> dict[str, float]:
+        self.commit_calls += 1
+        return {'parameter': parameter}
+
+    def primitive_offers(
+            self,
+            kind: Literal['straight', 'bend', 's', 'u'],
+            *,
+            in_ptype: str | None = None,
+            out_ptype: str | None = None,
+            **kwargs: Any,
+            ) -> tuple[Any, ...]:
+        _ = out_ptype
+        self.diagnostic_context_kwargs.append(kwargs.get('diagnostic_context'))
+        if kind == 'bend':
+            ccw = bool(kwargs['ccw'])
+            rotation = -pi / 2 if ccw else pi / 2
+            jog = 1 if ccw else -1
+            return (
+                BendOffer(
+                    in_ptype=in_ptype,
+                    out_ptype='wide',
+                    priority_bias=100,
+                    ccw=ccw,
+                    length_domain=(2, 2),
+                    endpoint_planner=lambda _length: Port((2, jog), rotation, ptype='wide'),
+                    commit_planner=self._commit,
+                    ),
+                BendOffer(
+                    in_ptype=in_ptype,
+                    out_ptype='wide',
+                    ccw=ccw,
+                    length_domain=(5, 5),
+                    endpoint_planner=lambda _length: Port((5, jog), rotation, ptype='wide'),
+                    commit_planner=self._commit,
+                    ),
+                )
+        if kind == 'u':
+            return (UOffer(
+                in_ptype=in_ptype,
+                out_ptype='wide',
+                jog_domain=(4, 4),
+                endpoint_planner=lambda _jog: Port((5, 4), 0, ptype='wide'),
+                commit_planner=self._commit,
+                ),)
+        return ()
+
+
+def test_route_error_reports_preferred_minimum_and_request_details() -> None:
+    tool = PreferredMinimumTool()
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.ccw('A', 1, out_ptype='wide', diagnostic_context='tool-value')
+
+    details = exc_info.value.details
+    assert isinstance(exc_info.value, BuildError)
+    assert details.operation == 'trace_to'
+    assert details.portspec == 'A'
+    assert details.in_ptype == 'wire'
+    assert details.out_ptype == 'wide'
+    assert details.request == {
+        'ccw': True,
+        'length': 1,
+        'out_ptype': 'wide',
+        'diagnostic_context': 'tool-value',
+        }
+    assert details.resolved_length == 1
+    assert details.resolved_jog is None
+    # The length-2 route exists, but normal cost ranking prefers length 5.
+    assert details.minimum_length == 5
+    assert details.minimum_attempted
+    assert not details.minimum_exhausted
+    assert details.minimum_cause is None
+    assert 'preferred_minimum_length: 5' in str(exc_info.value)
+    assert tool.commit_calls == 0
+    assert tool.diagnostic_context_kwargs
+    assert set(tool.diagnostic_context_kwargs) == {'tool-value'}
+    assert not p._paths
+    with pytest.raises(TypeError):
+        details.request['new'] = 'value'  # type: ignore[index]
+
+
+def test_route_error_reports_uturn_preferred_minimum() -> None:
+    tool = PreferredMinimumTool()
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.uturn('A', 4, length=1, out_ptype='wide')
+
+    details = exc_info.value.details
+    assert details.operation == 'uturn'
+    assert details.resolved_length == 1
+    assert details.resolved_jog == 4
+    assert details.minimum_length == 5
+    assert tool.commit_calls == 0
+
+
+def test_route_error_reports_no_route_at_any_length() -> None:
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=PathTool(layer='M1', width=2, ptype='wire'),
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.ccw('A', 10, out_ptype='optical')
+
+    details = exc_info.value.details
+    assert details.minimum_attempted
+    assert details.minimum_length is None
+    assert details.minimum_exhausted
+    assert details.minimum_cause is not None
+    assert 'no legal route exists at any length' in str(exc_info.value)
+
+
+@pytest.mark.parametrize('length', [-1, numpy.nan, numpy.inf])
+def test_invalid_route_length_fails_before_offer_query_or_dead_fallback(length: float) -> None:
+    tool = RequestCountingTool()
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=tool,
+        render='deferred',
+        ).set_dead()
+
+    with pytest.raises(RouteError) as exc_info:
+        p.ccw('A', length)
+
+    details = exc_info.value.details
+    assert not details.minimum_attempted
+    assert details.minimum_length is None
+    assert tool.offer_calls == 0
+    assert numpy.allclose(p.ports['A'].offset, (0, 0))
+
+
+def test_negative_position_length_reports_bound_without_offer_query() -> None:
+    tool = RequestCountingTool()
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.ccw('A', x=1)
+
+    details = exc_info.value.details
+    assert details.request == {'ccw': True, 'x': 1}
+    assert details.resolved_length == -1
+    assert not details.minimum_attempted
+    assert tool.offer_calls == 0
+
+
+def test_negative_bundle_length_reports_failing_port_and_bound() -> None:
+    tool = RequestCountingTool()
+    p = Pather(
+        Library(),
+        ports={
+            'A': Port((0, 0), rotation=0, ptype='wire'),
+            'B': Port((0, 4), rotation=0, ptype='wire'),
+            },
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.trace(['A', 'B'], True, emax=0, spacing=2)
+
+    details = exc_info.value.details
+    assert details.portspec == 'A'
+    assert details.request == {'ccw': True, 'emax': 0, 'spacing': 2}
+    assert details.resolved_length == -2
+    assert not details.minimum_attempted
+    assert tool.offer_calls == 0
+
+
+def test_negative_each_length_reports_failing_port_without_offer_query() -> None:
+    tool = RequestCountingTool()
+    p = Pather(
+        Library(),
+        ports={
+            'A': Port((0, 0), rotation=0, ptype='wire'),
+            'B': Port((0, 4), rotation=0, ptype='wire'),
+            },
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(RouteError) as exc_info:
+        p.trace(['A', 'B'], None, each=-2)
+
+    details = exc_info.value.details
+    assert details.portspec == 'A'
+    assert details.request == {'ccw': None, 'each': -2}
+    assert details.resolved_length == -2
+    assert not details.minimum_attempted
+    assert tool.offer_calls == 0
+
+
+@pytest.mark.parametrize(
+    'operation',
+    [
+        lambda p: p.trace([], None, length=1),
+        lambda p: p.trace_to([], None, length=1),
+        lambda p: p.jog([], 2, length=3),
+        lambda p: p.uturn([], 2, length=3),
+    ],
+    ids=['trace', 'trace_to', 'jog', 'uturn'],
+    )
+def test_pather_rejects_empty_route_selection_before_planning(operation: Any) -> None:
+    tool = RequestCountingTool()
+    p = Pather(Library(), tools=tool, render='deferred')
+
+    with pytest.raises(BuildError, match='at least one port'):
+        operation(p)
+
+    assert tool.offer_calls == 0
+    assert not p.ports
+    assert not p._paths
+
+
+@pytest.mark.parametrize(
+    'operation',
+    [
+        lambda p: p.trace(['A', 'A'], None, each=1),
+        lambda p: p.trace_to(['A', 'A'], None, xmin=-10),
+        lambda p: p.jog(['A', 'A'], 2, length=3, spacing=1),
+        lambda p: p.uturn(['A', 'A'], 2, length=3, spacing=1),
+        lambda p: p.at(['A', 'A']).straight(1),
+    ],
+    ids=['trace', 'trace_to', 'jog', 'uturn', 'port_pather'],
+    )
+def test_pather_rejects_duplicate_route_selection_before_planning(operation: Any) -> None:
+    tool = RequestCountingTool()
+    p = Pather(
+        Library(),
+        ports={'A': Port((0, 0), rotation=0, ptype='wire')},
+        tools=tool,
+        render='deferred',
+        )
+
+    with pytest.raises(BuildError, match=r"duplicates: \['A'\]"):
+        operation(p)
+
+    assert tool.offer_calls == 0
+    assert numpy.allclose(p.ports['A'].offset, (0, 0))
+    assert not p._paths
+
+
 def test_pather_jog_failed_two_bend_route_is_atomic() -> None:
     lib = Library()
     tool = PathTool(layer='M1', width=2, ptype='wire')
     p = Pather(lib, tools=tool, render='immediate')
     p.pattern.ports['A'] = Port((0, 0), rotation=0, ptype='wire')
 
-    with pytest.raises(BuildError, match='S-bend'):
+    with pytest.raises(RouteError, match='S-bend') as exc_info:
         p.jog('A', 1.5, length=1.5)
 
+    assert exc_info.value.details.minimum_length == 2
+    assert exc_info.value.details.resolved_jog == 1.5
+
     assert numpy.allclose(p.pattern.ports['A'].offset, (0, 0))
     assert p.pattern.ports['A'].rotation == 0
     assert len(p._paths['A']) == 0
@@ -593,9 +884,12 @@ def test_pather_uturn_failed_two_bend_route_is_atomic() -> None:
     p = Pather(lib, tools=tool)
     p.pattern.ports['A'] = Port((0, 0), rotation=0, ptype='wire')
 
-    with pytest.raises(BuildError, match='U-turn'):
+    with pytest.raises(RouteError, match='U-turn') as exc_info:
         p.uturn('A', 1.5, length=0)
 
+    assert exc_info.value.details.minimum_attempted
+    assert exc_info.value.details.minimum_length is None
+
     assert numpy.allclose(p.pattern.ports['A'].offset, (0, 0))
     assert p.pattern.ports['A'].rotation == 0
     assert len(p._paths['A']) == 0

masque/test/test_pather_core.py

@@ -5,7 +5,7 @@ import numpy
 from numpy import pi
 from numpy.testing import assert_allclose, assert_equal
 
-from masque import Pather, Library, Pattern, Port
+from masque import Pather, Library, Pattern, Port, RouteError
 from masque.builder import PathTool, PrimitiveOffer, StraightOffer
 from masque.builder.planner import RoutingPlanner
 from masque.error import BuildError, PortError
@@ -136,12 +136,13 @@ def test_pather_dead_ports() -> None:
     p = Pather(lib, ports={"in": Port((0, 0), 0)}, tools=tool)
     p.set_dead()
 
-    p.straight("in", -10)
+    with pytest.raises(RouteError, match='finite and nonnegative'):
+        p.straight("in", -10)
 
-    assert_allclose(p.ports["in"].offset, [10, 0], atol=1e-10)
+    assert_allclose(p.ports["in"].offset, [0, 0], atol=1e-10)
 
     p.straight("in", 20)
-    assert_allclose(p.ports["in"].offset, [-10, 0], atol=1e-10)
+    assert_allclose(p.ports["in"].offset, [-20, 0], atol=1e-10)
 
     assert not p.pattern.has_shapes()
 
@@ -394,9 +395,9 @@ def test_pather_dead_fallback_preserves_out_ptype() -> None:
     p.pattern.ports['A'] = Port((0, 0), rotation=0, ptype='wire')
     p.set_dead()
 
-    p.straight('A', -1000, out_ptype='other')
+    p.straight('A', 1000, out_ptype='other')
 
-    assert numpy.allclose(p.pattern.ports['A'].offset, (1000, 0))
+    assert numpy.allclose(p.pattern.ports['A'].offset, (-1000, 0))
     assert p.pattern.ports['A'].ptype == 'other'
     assert len(p._paths['A']) == 0
 

masque/test/test_pather_rendering.py

@@ -6,7 +6,7 @@ import numpy
 from numpy import pi
 from numpy.testing import assert_allclose
 
-from ..builder import Pather
+from ..builder import Pather, RouteError
 from ..builder.tools import PathTool, RenderStep, StraightOffer, Tool
 from ..error import BuildError
 from ..library import Library
@@ -122,9 +122,10 @@ def test_deferred_render_dead_ports() -> None:
     rp = Pather(lib, ports={"in": Port((0, 0), 0)}, tools=tool, render='deferred')
     rp.set_dead()
 
-    rp.straight("in", -10)
+    with pytest.raises(RouteError, match='finite and nonnegative'):
+        rp.straight("in", -10)
 
-    assert_allclose(rp.ports["in"].offset, [10, 0], atol=1e-10)
+    assert_allclose(rp.ports["in"].offset, [0, 0], atol=1e-10)
 
     assert len(rp._paths["in"]) == 0