19324 FIX HW/SW inventory: Fix flaky links to inventory tree or history

SUP-28176

Change-Id: I966e435ad548b4ab565c410abf84f4f4b68e440e

Author: si-23

.werks/19324.md

@@ -0,0 +1,18 @@
+[//]: # (werk v2)
+# HW/SW inventory: Fix flaky links to inventory tree or history
+
+key        | value
+---------- | ---
+date       | 2026-04-21T10:35:13+00:00
+version    | 2.4.0p27
+class      | fix
+edition    | cre
+component  | multisite
+level      | 1
+compatible | yes
+
+Different conditions were implemented for linking inventory views in
+`Services of host > Host > HW/SW inventory`,
+`Inventory of host > Host > HW/SW inventory` and
+`Inventory history of host > Host > HW/SW inventory`,
+so that the links could be present in one view but not in another. This has been fixed now.

cmk/gui/views/visual_type.py

@@ -158,13 +158,30 @@ def _compute_link_from_result(
     base_link_from: Callable[[SingleInfos, Rows, Visual, HTTPVariables], bool],
     has_inventory_tree: Callable[[HostName, SiteId, SDPath | None, bool], bool],
 ) -> bool:
-    if not base_link_from(linking_view_single_infos, linking_view_rows, visual, context_vars):
-        return False
-
     link_from = visual["link_from"]
     if not link_from:
         return True  # No link from filtering: Always display this.
 
+    if "has_inventory_tree" not in link_from and "has_inventory_tree_history" not in link_from:
+        # No inventory checks — delegate fully to base class.
+        return base_link_from(linking_view_single_infos, linking_view_rows, visual, context_vars)
+
+    # Inventory checks use context_vars directly and do not need row data. The base class
+    # returns False for empty rows, which would wrongly suppress inventory links on views
+    # whose datasource yields no rows (e.g. "Services of host" for a host with no services).
+    # Only the single_infos guard from the base class is still relevant here.
+    single_info_condition = link_from.get("single_infos")
+    if single_info_condition and not set(single_info_condition).issubset(linking_view_single_infos):
+        return False
+
+    # Non-inventory conditions (e.g. host_labels) must still be evaluated via the base class.
+    # We call it after the single_infos guard so a mismatch short-circuits before the base
+    # class can raise NotImplementedError for unsupported single_infos combinations.
+    _inventory_keys = {"has_inventory_tree", "has_inventory_tree_history", "single_infos"}
+    if link_from.keys() - _inventory_keys:
+        if not base_link_from(linking_view_single_infos, linking_view_rows, visual, context_vars):
+            return False
+
     context = dict(context_vars)
     if (hostname := context.get("host")) is None:
         # No host data? Keep old behaviour

tests/unit/cmk/gui/views/test_visual_type.py

@@ -115,10 +115,10 @@ def test_inventory_tree_link_empty_rows() -> None:
             [],
             visual,
             context_vars,
-            base_link_from=_base_checks_rows,
+            base_link_from=_base_returns_true,
             has_inventory_tree=_tree_found,
         )
-        is False
+        is True
     )
 
 
@@ -131,13 +131,175 @@ def test_inventory_tree_history_link_empty_rows() -> None:
             [],
             visual,
             context_vars,
+            base_link_from=_base_returns_true,
+            has_inventory_tree=_tree_found,
+        )
+        is True
+    )
+
+
+def test_label_filter_suppresses_link_when_rows_empty() -> None:
+    visual = _make_visual(
+        {
+            "single_infos": ["host"],
+            "host_labels": {"cmk/os-family": "linux"},
+            "has_inventory_tree": _path("hardware"),
+        }
+    )
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [],
+            visual,
+            context_vars,
             base_link_from=_base_checks_rows,
             has_inventory_tree=_tree_found,
         )
         is False
     )
 
 
+def test_label_filter_suppresses_link_when_label_mismatches() -> None:
+    visual = _make_visual(
+        {
+            "single_infos": ["host"],
+            "host_labels": {"cmk/os-family": "linux"},
+            "has_inventory_tree": _path("hardware"),
+        }
+    )
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    row: dict[str, object] = {}
+
+    def _base_rejects(
+        single_infos: SingleInfos, rows: Rows, visual: Visual, context_vars: HTTPVariables
+    ) -> bool:
+        return False
+
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [row],
+            visual,
+            context_vars,
+            base_link_from=_base_rejects,
+            has_inventory_tree=_tree_found,
+        )
+        is False
+    )
+
+
+def test_label_and_inventory_both_match_shows_link() -> None:
+    visual = _make_visual(
+        {
+            "single_infos": ["host"],
+            "host_labels": {"cmk/os-family": "linux"},
+            "has_inventory_tree": _path("hardware"),
+        }
+    )
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    row: dict[str, object] = {}
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [row],
+            visual,
+            context_vars,
+            base_link_from=_base_checks_rows,
+            has_inventory_tree=_tree_found,
+        )
+        is True
+    )
+
+
+def test_label_matches_but_inventory_missing_suppresses_link() -> None:
+    visual = _make_visual(
+        {
+            "single_infos": ["host"],
+            "host_labels": {"cmk/os-family": "linux"},
+            "has_inventory_tree": _path("hardware"),
+        }
+    )
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    row: dict[str, object] = {}
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [row],
+            visual,
+            context_vars,
+            base_link_from=_base_checks_rows,
+            has_inventory_tree=_tree_not_found,
+        )
+        is False
+    )
+
+
+def test_single_infos_not_matching_returns_false() -> None:
+    visual = _make_visual({"single_infos": ["host"], "has_inventory_tree": _path("hardware")})
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "s")]
+    assert (
+        _compute_link_from_result(
+            [],
+            [],
+            visual,
+            context_vars,
+            base_link_from=_base_returns_true,
+            has_inventory_tree=_tree_found,
+        )
+        is False
+    )
+
+
+def test_single_infos_matching_proceeds() -> None:
+    visual = _make_visual({"single_infos": ["host"], "has_inventory_tree": _path("hardware")})
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [],
+            visual,
+            context_vars,
+            base_link_from=_base_returns_true,
+            has_inventory_tree=_tree_found,
+        )
+        is True
+    )
+
+
+def test_single_infos_partially_matching_returns_false() -> None:
+    visual = _make_visual(
+        {"single_infos": ["host", "service"], "has_inventory_tree": _path("hardware")}
+    )
+    assert (
+        _compute_link_from_result(
+            ["host"],
+            [],
+            visual,
+            [],
+            base_link_from=_base_returns_true,
+            has_inventory_tree=_tree_found,
+        )
+        is False
+    )
+
+
+def test_no_single_infos_condition_proceeds() -> None:
+    visual = _make_visual({"has_inventory_tree": _path("hardware")})
+    context_vars: HTTPVariables = [("host", "myhost"), ("site", "mysite")]
+    assert (
+        _compute_link_from_result(
+            [],
+            [],
+            visual,
+            context_vars,
+            base_link_from=_base_returns_true,
+            has_inventory_tree=_tree_found,
+        )
+        is True
+    )
+
+
 def test_no_host_in_context_returns_true() -> None:
     visual = _make_visual({"has_inventory_tree": _path("hardware")})
     assert (