solver: improve verbose output for dependencies with extras (#8834)

src/poetry/mixology/incompatibility.py

@@ -432,7 +432,8 @@ def _terse(self, term: Term, allow_every: bool = False) -> str:
 
         if term.dependency.source_type:
             return str(term.dependency)
-        return f"{term.dependency.pretty_name} ({term.dependency.pretty_constraint})"
+        pretty_name = term.dependency.complete_pretty_name
+        return f"{pretty_name} ({term.dependency.pretty_constraint})"
 
     def _single_term_where(self, callable: Callable[[Term], bool]) -> Term | None:
         found = None

tests/mixology/test_incompatibility.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import pytest
+
+from poetry.core.packages.dependency import Dependency
+from poetry.core.packages.url_dependency import URLDependency
+
+from poetry.mixology.incompatibility import Incompatibility
+from poetry.mixology.incompatibility_cause import DependencyCause
+from poetry.mixology.term import Term
+
+
+def get_url_dependency(name: str, url: str, version: str) -> URLDependency:
+    dependency = URLDependency(name, url)
+    dependency.constraint = version  # type: ignore[assignment]
+    return dependency
+
+
+@pytest.mark.parametrize(
+    ("dependency1", "dependency2", "expected"),
+    [
+        (
+            Dependency("foo", "1.0"),
+            Dependency("bar", "2.0"),
+            "foo (1.0) depends on bar (2.0)",
+        ),
+        (
+            Dependency("foo", "1.0"),
+            Dependency("bar", "^1.0"),
+            "foo (1.0) depends on bar (^1.0)",
+        ),
+        (
+            Dependency("foo", "1.0"),
+            get_url_dependency("bar", "https://example.com/bar.whl", "1.1"),
+            "foo (1.0) depends on bar (1.1) @ https://example.com/bar.whl",
+        ),
+        (
+            Dependency("foo", "1.0", extras=["bar"]),
+            Dependency("foo", "1.0"),
+            "foo[bar] (1.0) depends on foo (1.0)",
+        ),
+    ],
+)
+def test_str_dependency_cause(
+    dependency1: Dependency, dependency2: Dependency, expected: str
+) -> None:
+    incompatibility = Incompatibility(
+        [Term(dependency1, True), Term(dependency2, False)], DependencyCause()
+    )
+    assert str(incompatibility) == expected