search_for should not raise ValueError to indicate that a package could not be found (#6790)

subclasses of ValueError like UnicodeEncodeError have to be propagated (see #6784)

src/poetry/mixology/incompatibility.py

@@ -5,7 +5,6 @@ from typing import TYPE_CHECKING
 from poetry.mixology.incompatibility_cause import ConflictCause
 from poetry.mixology.incompatibility_cause import DependencyCause
 from poetry.mixology.incompatibility_cause import NoVersionsCause
-from poetry.mixology.incompatibility_cause import PackageNotFoundCause
 from poetry.mixology.incompatibility_cause import PlatformCause
 from poetry.mixology.incompatibility_cause import PythonCause
 from poetry.mixology.incompatibility_cause import RootCause
@@ -146,11 +145,6 @@ class Incompatibility:
                 f"no versions of {self._terms[0].dependency.name} match"
                 f" {self._terms[0].constraint}"
             )
-        elif isinstance(self._cause, PackageNotFoundCause):
-            assert len(self._terms) == 1
-            assert self._terms[0].is_positive()
-
-            return f"{self._terms[0].dependency.name} doesn't exist"
         elif isinstance(self._cause, RootCause):
             assert len(self._terms) == 1
             assert not self._terms[0].is_positive()
@@ -420,8 +414,6 @@ class Incompatibility:
             buffer.append(f"which requires Python {cause.python_version}")
         elif isinstance(latter.cause, NoVersionsCause):
             buffer.append("which doesn't match any versions")
-        elif isinstance(latter.cause, PackageNotFoundCause):
-            buffer.append("which doesn't exist")
         else:
             buffer.append("which is forbidden")
 

src/poetry/mixology/incompatibility_cause.py

@@ -79,17 +79,3 @@ class PlatformCause(IncompatibilityCause):
     @property
     def platform(self) -> str:
         return self._platform
-
-
-class PackageNotFoundCause(IncompatibilityCause):
-    """
-    The incompatibility represents a package that couldn't be found by its
-    source.
-    """
-
-    def __init__(self, error: Exception) -> None:
-        self._error = error
-
-    @property
-    def error(self) -> Exception:
-        return self._error

src/poetry/mixology/version_solver.py

@@ -3,7 +3,6 @@ from __future__ import annotations
 import functools
 import time
 
-from contextlib import suppress
 from typing import TYPE_CHECKING
 
 from poetry.core.packages.dependency import Dependency
@@ -12,7 +11,6 @@ from poetry.mixology.failure import SolveFailure
 from poetry.mixology.incompatibility import Incompatibility
 from poetry.mixology.incompatibility_cause import ConflictCause
 from poetry.mixology.incompatibility_cause import NoVersionsCause
-from poetry.mixology.incompatibility_cause import PackageNotFoundCause
 from poetry.mixology.incompatibility_cause import RootCause
 from poetry.mixology.partial_solution import PartialSolution
 from poetry.mixology.result import SolverResult
@@ -395,10 +393,8 @@ class VersionSolver:
                 if locked:
                     return is_specific_marker, Preference.LOCKED, 1
 
-            try:
-                num_packages = len(self._dependency_cache.search_for(dependency))
-            except ValueError:
-                num_packages = 0
+            num_packages = len(self._dependency_cache.search_for(dependency))
+
             if num_packages < 2:
                 preference = Preference.NO_CHOICE
             elif use_latest:
@@ -414,28 +410,8 @@ class VersionSolver:
 
         locked = self._provider.get_locked(dependency)
         if locked is None:
-            try:
-                packages = self._dependency_cache.search_for(dependency)
-            except ValueError as e:
-                self._add_incompatibility(
-                    Incompatibility([Term(dependency, True)], PackageNotFoundCause(e))
-                )
-                complete_name: str = dependency.complete_name
-                return complete_name
-
-            package = None
-            if locked is not None:
-                package = next(
-                    (
-                        p
-                        for p in packages
-                        if p.package.version == locked.package.version
-                    ),
-                    None,
-                )
-            if package is None:
-                with suppress(IndexError):
-                    package = packages[0]
+            packages = self._dependency_cache.search_for(dependency)
+            package = next(iter(packages), None)
 
             if package is None:
                 # If there are no versions that satisfy the constraint,