From c5277e4e9d374ca99d20d4f92fa42e17d48da678 Mon Sep 17 00:00:00 2001
From: Victor Makarov <vitja@yandex-team.ru>
Date: Fri, 24 Mar 2023 08:29:08 +0300
Subject: [PATCH 1/4] Detailed error message on hook registration conflict

---
 src/pluggy/_hooks.py       |  6 +++++-
 testing/test_hookcaller.py | 16 ++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/pluggy/_hooks.py b/src/pluggy/_hooks.py
index 79dd9cb4..9f230db3 100644
--- a/src/pluggy/_hooks.py
+++ b/src/pluggy/_hooks.py
@@ -337,7 +337,11 @@ def set_specification(
         specmodule_or_class: _Namespace,
         spec_opts: "_HookSpecOpts",
     ) -> None:
-        assert not self.has_spec()
+        if self.has_spec():
+            raise RuntimeError(
+                f"Hook {self.spec.name!r} is already registered "
+                f"within namespace {self.spec.namespace}"
+            )
         self.spec = HookSpec(specmodule_or_class, self.name, spec_opts)
         if spec_opts.get("historic"):
             self._call_history = []
diff --git a/testing/test_hookcaller.py b/testing/test_hookcaller.py
index 5e69a003..a12a2ad1 100644
--- a/testing/test_hookcaller.py
+++ b/testing/test_hookcaller.py
@@ -405,3 +405,19 @@ def hello(self, arg: int) -> int:
     pm.register(Plugin2())
     with pytest.raises(PluginValidationError):
         pm.check_pending()
+
+
+def test_hook_conflict(pm: PluginManager) -> None:
+    class Api1:
+        @hookspec
+        def conflict(self) -> None:
+            pass
+
+    class Api2:
+        @hookspec
+        def conflict(self) -> None:
+            pass
+
+    pm.add_hookspecs(Api1)
+    with pytest.raises(RuntimeError):
+        pm.add_hookspecs(Api2)

From c501a32b34f177a7cf1f0511bbaecc2110b237bb Mon Sep 17 00:00:00 2001
From: Victor Makarov <vitja@yandex-team.ru>
Date: Fri, 24 Mar 2023 08:39:54 +0300
Subject: [PATCH 2/4] mypy fix

---
 src/pluggy/_hooks.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pluggy/_hooks.py b/src/pluggy/_hooks.py
index 9f230db3..de4c7cf2 100644
--- a/src/pluggy/_hooks.py
+++ b/src/pluggy/_hooks.py
@@ -337,7 +337,7 @@ def set_specification(
         specmodule_or_class: _Namespace,
         spec_opts: "_HookSpecOpts",
     ) -> None:
-        if self.has_spec():
+        if self.spec is not None:
             raise RuntimeError(
                 f"Hook {self.spec.name!r} is already registered "
                 f"within namespace {self.spec.namespace}"

From aac593436a655905e77ce63dd6446d7503834e8d Mon Sep 17 00:00:00 2001
From: Victor Makarov <vitja@yandex-team.ru>
Date: Fri, 24 Mar 2023 09:15:34 +0300
Subject: [PATCH 3/4] review fixes

---
 src/pluggy/_hooks.py       | 2 +-
 testing/test_hookcaller.py | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/pluggy/_hooks.py b/src/pluggy/_hooks.py
index de4c7cf2..6fe5a6a0 100644
--- a/src/pluggy/_hooks.py
+++ b/src/pluggy/_hooks.py
@@ -338,7 +338,7 @@ def set_specification(
         spec_opts: "_HookSpecOpts",
     ) -> None:
         if self.spec is not None:
-            raise RuntimeError(
+            raise ValueError(
                 f"Hook {self.spec.name!r} is already registered "
                 f"within namespace {self.spec.namespace}"
             )
diff --git a/testing/test_hookcaller.py b/testing/test_hookcaller.py
index a12a2ad1..5880cd9c 100644
--- a/testing/test_hookcaller.py
+++ b/testing/test_hookcaller.py
@@ -419,5 +419,9 @@ def conflict(self) -> None:
             pass
 
     pm.add_hookspecs(Api1)
-    with pytest.raises(RuntimeError):
+    with pytest.raises(ValueError) as exc:
         pm.add_hookspecs(Api2)
+    assert str(exc.value) == (
+        "Hook 'conflict' is already registered within namespace "
+        "<class 'test_hookcaller.test_hook_conflict.<locals>.Api1'>"
+    )

From 33a6936813009208a97e6b194216a3dbe7ab2e57 Mon Sep 17 00:00:00 2001
From: Victor Makarov <vitja@yandex-team.ru>
Date: Fri, 24 Mar 2023 09:45:06 +0300
Subject: [PATCH 4/4] fix

---
 testing/test_hookcaller.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/testing/test_hookcaller.py b/testing/test_hookcaller.py
index 5880cd9c..1f0c0a43 100644
--- a/testing/test_hookcaller.py
+++ b/testing/test_hookcaller.py
@@ -411,12 +411,12 @@ def test_hook_conflict(pm: PluginManager) -> None:
     class Api1:
         @hookspec
         def conflict(self) -> None:
-            pass
+            """Api1 hook"""
 
     class Api2:
         @hookspec
         def conflict(self) -> None:
-            pass
+            """Api2 hook"""
 
     pm.add_hookspecs(Api1)
     with pytest.raises(ValueError) as exc: