Log a manifest-name match and ignore a dependency on the requester itself

A match found only through a library's manifest name is logged at info,
so a chance name collision can be pinned to the right package. A
manifest listing its own name as a dependency no longer fetches a
second copy of itself.

esphome/platformio/library.py

@@ -1002,10 +1002,28 @@ def _satisfying_key(
     for key, component in candidates:
         manifest_name = component.data.get("name")
         if isinstance(manifest_name, str) and manifest_name.lower() == wanted:
+            # Visible, so a chance name collision can be pinned to the right package
+            _LOGGER.info(
+                "Dependency %s of %s satisfied by %s through its manifest name",
+                name,
+                requester,
+                key,
+            )
             return key
     return None
 
 
+def _own_names(
+    key: str, nodes: dict[str, _LibNode], components: dict[str, ConvertedLibrary]
+) -> set[str]:
+    """The lower-case key, package and manifest names a resolved library goes by."""
+    names = {key.lower(), (nodes[key].pkgname or key).lower()}
+    manifest_name = components[key].data.get("name")
+    if isinstance(manifest_name, str):
+        names.add(manifest_name.lower())
+    return names
+
+
 def _fetch_source(
     component: ConvertedLibrary,
     salt: str,
@@ -1248,6 +1266,11 @@ def convert_libraries(
         for requester, dependencies in pending_versionless.items():
             for dependency in dependencies:
                 name, owner = dependency["name"], dependency.get("owner")
+                if not owner and name.lower() in _own_names(
+                    requester, nodes, components
+                ):
+                    _LOGGER.debug("Dependency %s of %s names itself", name, requester)
+                    continue
                 # A library in the graph beats a bundled copy, as on the Arduino backend
                 if (
                     match := _satisfying_key(name, owner, requester, nodes, components)

tests/unit_tests/test_platformio_library.py

@@ -1261,7 +1261,7 @@ def test_versionless_url_ish_dependency_name_warns_cleanly(
 
 
 def test_versionless_dependency_matching_resolved_manifest_name_is_wired(
-    tmp_path, monkeypatch
+    tmp_path, monkeypatch, caplog: pytest.LogCaptureFixture
 ) -> None:
     """A bare name no package name matches is satisfied by a listed component's
     manifest name (a fork published under another package name)."""
@@ -1273,12 +1273,40 @@ def test_versionless_dependency_matching_resolved_manifest_name_is_wired(
             "esphome/B-fork": {"name": "B"},
         },
     )
-    top = convert_libraries(
-        [Library("esphome/A", None, None), Library("esphome/B-fork", None, None)],
-        _backend(),
-    )
+    with caplog.at_level(logging.INFO):
+        top = convert_libraries(
+            [Library("esphome/A", None, None), Library("esphome/B-fork", None, None)],
+            _backend(),
+        )
     assert [d.name for d in top[0].dependencies] == ["esphome/B-fork"]
     assert asked == [("esphome", "A"), ("esphome", "B-fork")]
+    assert (
+        "Dependency B of esphome/A satisfied by esphome/B-fork through its manifest name"
+        in caplog.text
+    )
+
+
+def test_dependency_naming_the_requester_itself_is_ignored(
+    tmp_path, monkeypatch
+) -> None:
+    """A manifest that lists its own name as a dependency neither fetches a
+    second copy of itself nor gains a self edge."""
+    asked = _patch_download_with_manifests(
+        monkeypatch,
+        tmp_path,
+        {
+            "esphome/A": "name=A\ndepends=a, esphome/A\n",
+            # No manifest name: the package name still identifies it
+            "esphome/C": {"dependencies": [{"name": "C"}]},
+        },
+        properties=("esphome/A",),
+    )
+    top = convert_libraries(
+        [Library("esphome/A", "1.0.0", None), Library("esphome/C", "1.0.0", None)],
+        _backend(),
+    )
+    assert [c.dependencies for c in top] == [[], []]
+    assert asked == [("esphome", "A"), ("esphome", "C")]
 
 
 def test_versionless_dependency_settles_after_the_graph(