From a533ba946909ebf6fcb1bf6d0ac776e4cedd98f5 Mon Sep 17 00:00:00 2001
From: "david.jones" <david.jones@datadoghq.com>
Date: Mon, 7 Sep 2026 16:51:07 +0100
Subject: [PATCH 1/5] update nav

---
 hugo/assets/scripts/components/async-loading.js | 15 +++++++++++++++
 hugo/assets/scripts/datadog-docs.js             |  2 +-
 hugo/layouts/partials/nav/left-nav.html         |  7 +++++--
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/hugo/assets/scripts/components/async-loading.js b/hugo/assets/scripts/components/async-loading.js
index c43c864e648..9e0973d30d5 100644
--- a/hugo/assets/scripts/components/async-loading.js
+++ b/hugo/assets/scripts/components/async-loading.js
@@ -10,6 +10,7 @@ import {updateMainContentAnchors, reloadWistiaVidScripts, gtag, getCookieByName
 import configDocs from '../config/config-docs';
 import { redirectCodeLang, addCodeTabEventListeners, addCodeBlockVisibilityToggleEventListeners, activateCodeLangNav, toggleMultiCodeLangNav } from './code-languages'; // eslint-disable-line import/no-cycle
 import { loadInstantSearch } from './instantsearch';
+import { getPathElement } from '../datadog-docs'; // eslint-disable-line import/no-cycle
 
 const { env } = document.documentElement.dataset;
 const { gaTag } = configDocs[env];
@@ -177,6 +178,20 @@ function loadPage(newUrl) {
 
                 // update mainContent-wrapper classes
                 mainContentWrapper.className = `${newmainContentWrapper.classList}`;
+
+                // The left nav is server-rendered scoped to the current page's top-level section
+                // (see hugo/layouts/partials/nav/left-nav.html), so its content must be synced on
+                // every navigation -- otherwise navigating into a different section would leave the
+                // old section's nav items in place instead of the new section's. Swapping innerHTML
+                // (rather than replacing the container node) preserves the click listener bound to
+                // it in datadog-docs.js.
+                const currentLeftNav = document.querySelector('.sidenav-nav-js-load');
+                const newLeftNav = newDocument.querySelector('.sidenav-nav-js-load');
+
+                if (currentLeftNav && newLeftNav) {
+                    currentLeftNav.innerHTML = newLeftNav.innerHTML;
+                    getPathElement();
+                }
             } else {
                 window.location.href = newUrl;
             }
diff --git a/hugo/assets/scripts/datadog-docs.js b/hugo/assets/scripts/datadog-docs.js
index 540839da76f..6abfec6446b 100644
--- a/hugo/assets/scripts/datadog-docs.js
+++ b/hugo/assets/scripts/datadog-docs.js
@@ -178,7 +178,7 @@ function hasParentLi(el) {
     }
 }
 
-function getPathElement(event = null) {
+export function getPathElement(event = null) {
     let path = window.location.pathname;
     const activeMenus = document.querySelectorAll(
         '.side .sidenav-nav-js-load .active, header .sidenav-nav-js-load .active'
diff --git a/hugo/layouts/partials/nav/left-nav.html b/hugo/layouts/partials/nav/left-nav.html
index d03fe06ecae..33935040efb 100644
--- a/hugo/layouts/partials/nav/left-nav.html
+++ b/hugo/layouts/partials/nav/left-nav.html
@@ -29,8 +29,11 @@
         <ul class="list-unstyled">
             {{ range .Children }}
                 {{/*  LEVEL 1  */}}
+                {{/* Levels 3-4 are only rendered for the top-level section containing the current page, to avoid
+                     shipping every product's full sub-nav on every page (see DOCS nav HTML size investigation). */}}
+                {{ $isCurrentTopSection := $currentPage.HasMenuCurrent "main" . }}
                 <li class="nav-top-level {{ if (not (or (in $excludeAsync .Identifier) (and (in .URL "api/") (not (in .URL "_api/")) (not (in .URL "-api/"))))) }} js-load {{ end }}
-                {{ if $currentPage.HasMenuCurrent "main" . }}active{{ end }}">
+                {{ if $isCurrentTopSection }}active{{ end }}">
                     {{ $url_without_anchor = (index (split .URL "#") 0) }}
                     <a href="{{ .URL | relLangURL }}" class="d-flex align-items-center" data-path="{{ trim (print $branchPath ((print $url_without_anchor) | relLangURL)) "/" }}" data-skip="{{ .Params.skip | not | not }}">
                         {{ if .Pre }}
@@ -52,7 +55,7 @@
                                     {{ end }}
                                     <span>{{ .Name }}</span>
                                 </a>
-                            {{ if .HasChildren }}
+                            {{ if (and .HasChildren $isCurrentTopSection) }}
                                 <ul class="list-unstyled sub-menu {{ if (or (eq .Name "Guides") (eq .Name "Widget Types") (eq .Name "Monitor Types")) }} d-none {{ end }}">
                                 {{/*  LEVEL 3  */}}
                                 {{ range .Children }}

From 82786b20c7abd426c65f87250a9527e9cb78746b Mon Sep 17 00:00:00 2001
From: "david.jones" <david.jones@datadoghq.com>
Date: Thu, 10 Sep 2026 14:53:30 +0100
Subject: [PATCH 2/5] catch descendants too

---
 hugo/layouts/partials/nav/left-nav.html | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hugo/layouts/partials/nav/left-nav.html b/hugo/layouts/partials/nav/left-nav.html
index 33935040efb..523e56e467d 100644
--- a/hugo/layouts/partials/nav/left-nav.html
+++ b/hugo/layouts/partials/nav/left-nav.html
@@ -30,8 +30,10 @@
             {{ range .Children }}
                 {{/*  LEVEL 1  */}}
                 {{/* Levels 3-4 are only rendered for the top-level section containing the current page, to avoid
-                     shipping every product's full sub-nav on every page (see DOCS nav HTML size investigation). */}}
-                {{ $isCurrentTopSection := $currentPage.HasMenuCurrent "main" . }}
+                     shipping every product's full sub-nav on every page (see DOCS nav HTML size investigation).
+                     HasMenuCurrent is true only for descendants of this entry, not the entry's own page, so it's
+                     combined with IsMenuCurrent to also cover being on the section's own landing page. */}}
+                {{ $isCurrentTopSection := or ($currentPage.IsMenuCurrent "main" .) ($currentPage.HasMenuCurrent "main" .) }}
                 <li class="nav-top-level {{ if (not (or (in $excludeAsync .Identifier) (and (in .URL "api/") (not (in .URL "_api/")) (not (in .URL "-api/"))))) }} js-load {{ end }}
                 {{ if $isCurrentTopSection }}active{{ end }}">
                     {{ $url_without_anchor = (index (split .URL "#") 0) }}

From 183092717c8ca1f7bb407b1e7bfea9a9c7f14f3f Mon Sep 17 00:00:00 2001
From: "david.jones" <david.jones@datadoghq.com>
Date: Fri, 11 Sep 2026 15:24:16 +0100
Subject: [PATCH 3/5] update

---
 hugo/layouts/partials/nav/left-nav.html         | 11 ++++++++---
 hugo/layouts/partials/sidenav/main-sidenav.html | 11 ++++++++++-
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/hugo/layouts/partials/nav/left-nav.html b/hugo/layouts/partials/nav/left-nav.html
index 523e56e467d..5f07103cc9d 100644
--- a/hugo/layouts/partials/nav/left-nav.html
+++ b/hugo/layouts/partials/nav/left-nav.html
@@ -22,6 +22,7 @@
 {{ $url_without_anchor := "" }}
 
 {{ $currentPage := . }}
+{{ $curURL := trim $currentPage.RelPermalink "/" }}
 {{ range $menu }}
     {{ if .HasChildren }}
         {{/*  HEADER  */}}
@@ -31,9 +32,13 @@
                 {{/*  LEVEL 1  */}}
                 {{/* Levels 3-4 are only rendered for the top-level section containing the current page, to avoid
                      shipping every product's full sub-nav on every page (see DOCS nav HTML size investigation).
-                     HasMenuCurrent is true only for descendants of this entry, not the entry's own page, so it's
-                     combined with IsMenuCurrent to also cover being on the section's own landing page. */}}
-                {{ $isCurrentTopSection := or ($currentPage.IsMenuCurrent "main" .) ($currentPage.HasMenuCurrent "main" .) }}
+                     This site's main menu is defined entirely in config as plain url: strings, not via page
+                     front matter, so entries have no .Page and .IsMenuCurrent/.HasMenuCurrent (which rely on
+                     .Page identity) never match -- comparing URLs directly is what actually works here. Keep
+                     this in sync with nav/current-top-section.html, which computes the same thing for use as
+                     this partial's cache key. */}}
+                {{ $menuURL := trim (.URL | relLangURL) "/" }}
+                {{ $isCurrentTopSection := and (ne $menuURL "") (or (eq $curURL $menuURL) (strings.HasPrefix $curURL (printf "%s/" $menuURL))) }}
                 <li class="nav-top-level {{ if (not (or (in $excludeAsync .Identifier) (and (in .URL "api/") (not (in .URL "_api/")) (not (in .URL "-api/"))))) }} js-load {{ end }}
                 {{ if $isCurrentTopSection }}active{{ end }}">
                     {{ $url_without_anchor = (index (split .URL "#") 0) }}
diff --git a/hugo/layouts/partials/sidenav/main-sidenav.html b/hugo/layouts/partials/sidenav/main-sidenav.html
index 6e072b54913..c960512746a 100644
--- a/hugo/layouts/partials/sidenav/main-sidenav.html
+++ b/hugo/layouts/partials/sidenav/main-sidenav.html
@@ -16,7 +16,16 @@
             {{ end}}
 
             <div class="sidenav-nav sidenav-nav-js-load">
-                {{ partialCached "nav/left-nav.html" . .Section .Site.Language.Lang }}
+                {{/*
+                    left-nav.html's rendered HTML depends on which top-level main-menu entry the
+                    current page belongs to (see nav/current-top-section.html), not on .Section --
+                    two pages can share a Hugo content section while mapping to different (or no)
+                    top-level menu entries. Caching by .Section alone previously let a single
+                    page's render (whichever one Hugo happened to build first for that section)
+                    be served, incorrectly, for every other page in that section.
+                */}}
+                {{ $currentTopSection := partial "nav/current-top-section.html" . }}
+                {{ partialCached "nav/left-nav.html" . $currentTopSection .Site.Language.Lang }}
             </div>
         </div>
     </div>

From 7136f9b89f0e205f8e8b962878e3ec6cc27b5c3c Mon Sep 17 00:00:00 2001
From: "david.jones" <david.jones@datadoghq.com>
Date: Fri, 11 Sep 2026 15:51:09 +0100
Subject: [PATCH 4/5] update

---
 .../partials/nav/current-top-section.html     | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 hugo/layouts/partials/nav/current-top-section.html

diff --git a/hugo/layouts/partials/nav/current-top-section.html b/hugo/layouts/partials/nav/current-top-section.html
new file mode 100644
index 00000000000..6bd35ef3407
--- /dev/null
+++ b/hugo/layouts/partials/nav/current-top-section.html
@@ -0,0 +1,27 @@
+{{- /*
+  Returns the Identifier of the top-level main-menu entry (Level 1, e.g. "APM", "Profiler")
+  that the current page belongs to, or "" if the page isn't part of the main menu tree.
+
+  left-nav.html only renders a top-level entry's Levels 3-4 when the current page belongs to
+  that entry, so this value is exactly what left-nav.html's rendered HTML depends on. It's
+  computed here, up front, so it can be used as the partialCached key for left-nav.html --
+  caching by .Section alone is unsound, since two pages can share a Hugo content section while
+  belonging to different (or no) top-level menu entries, or a page may not be in the menu at all.
+
+  This site's main menu is defined entirely in config (config/_default/menus/main.*.yaml) as
+  plain url: strings, not via page front matter, so entries have no .Page and Hugo's built-in
+  .IsMenuCurrent/.HasMenuCurrent (which rely on .Page identity) never match -- comparing URLs
+  directly is what actually works here.
+*/ -}}
+{{- $currentPage := . -}}
+{{- $curURL := trim $currentPage.RelPermalink "/" -}}
+{{- $identifier := "" -}}
+{{- range .Site.Menus.main -}}
+    {{- range .Children -}}
+        {{- $menuURL := trim (.URL | relLangURL) "/" -}}
+        {{- if and (eq $identifier "") (ne $menuURL "") (or (eq $curURL $menuURL) (strings.HasPrefix $curURL (printf "%s/" $menuURL))) -}}
+            {{- $identifier = .Identifier -}}
+        {{- end -}}
+    {{- end -}}
+{{- end -}}
+{{- $identifier -}}

From dc6812d1b91d120939368a5700512e64bba5b455 Mon Sep 17 00:00:00 2001
From: "david.jones" <david.jones@datadoghq.com>
Date: Fri, 11 Sep 2026 21:02:12 +0100
Subject: [PATCH 5/5] update

---
 .../scripts/components/async-loading.js       |  9 ++----
 .../partials/nav/current-top-section.html     | 29 +++++++++----------
 hugo/layouts/partials/nav/left-nav.html       | 12 ++++----
 .../partials/sidenav/main-sidenav.html        | 10 ++-----
 4 files changed, 24 insertions(+), 36 deletions(-)

diff --git a/hugo/assets/scripts/components/async-loading.js b/hugo/assets/scripts/components/async-loading.js
index 9e0973d30d5..f86496caf1e 100644
--- a/hugo/assets/scripts/components/async-loading.js
+++ b/hugo/assets/scripts/components/async-loading.js
@@ -179,12 +179,9 @@ function loadPage(newUrl) {
                 // update mainContent-wrapper classes
                 mainContentWrapper.className = `${newmainContentWrapper.classList}`;
 
-                // The left nav is server-rendered scoped to the current page's top-level section
-                // (see hugo/layouts/partials/nav/left-nav.html), so its content must be synced on
-                // every navigation -- otherwise navigating into a different section would leave the
-                // old section's nav items in place instead of the new section's. Swapping innerHTML
-                // (rather than replacing the container node) preserves the click listener bound to
-                // it in datadog-docs.js.
+                // left-nav.html renders scoped to the page's section, so it must be resynced on
+                // every pjax nav or the old section's items would linger. innerHTML swap (not node
+                // replacement) preserves the click listener bound to this container in datadog-docs.js.
                 const currentLeftNav = document.querySelector('.sidenav-nav-js-load');
                 const newLeftNav = newDocument.querySelector('.sidenav-nav-js-load');
 
diff --git a/hugo/layouts/partials/nav/current-top-section.html b/hugo/layouts/partials/nav/current-top-section.html
index 6bd35ef3407..cae83c0c8d8 100644
--- a/hugo/layouts/partials/nav/current-top-section.html
+++ b/hugo/layouts/partials/nav/current-top-section.html
@@ -1,27 +1,26 @@
 {{- /*
-  Returns the Identifier of the top-level main-menu entry (Level 1, e.g. "APM", "Profiler")
-  that the current page belongs to, or "" if the page isn't part of the main menu tree.
+  Returns the pipe-delimited identifiers of every top-level main-menu entry (e.g. "apm",
+  "logs") whose URL matches the current page, or "" if none do.
 
-  left-nav.html only renders a top-level entry's Levels 3-4 when the current page belongs to
-  that entry, so this value is exactly what left-nav.html's rendered HTML depends on. It's
-  computed here, up front, so it can be used as the partialCached key for left-nav.html --
-  caching by .Section alone is unsound, since two pages can share a Hugo content section while
-  belonging to different (or no) top-level menu entries, or a page may not be in the menu at all.
+  left-nav.html independently checks each top-level entry against the current page to decide
+  whether to render that entry's Levels 3-4, so this full match set -- not just one identifier
+  -- is what left-nav.html's rendered HTML depends on. It's used as that partial's partialCached
+  key; keying by .Section, or by only the first match, is unsound because menu entries can nest
+  (e.g. "security/" and "security/cloud_siem/" are sibling top-level entries), which would let
+  two pages with different actual matches share the same key.
 
-  This site's main menu is defined entirely in config (config/_default/menus/main.*.yaml) as
-  plain url: strings, not via page front matter, so entries have no .Page and Hugo's built-in
-  .IsMenuCurrent/.HasMenuCurrent (which rely on .Page identity) never match -- comparing URLs
-  directly is what actually works here.
+  This menu is config-defined (plain url: strings, no page front matter), so entries have no
+  .Page and Hugo's .IsMenuCurrent/.HasMenuCurrent never match -- comparing URLs directly works.
 */ -}}
 {{- $currentPage := . -}}
 {{- $curURL := trim $currentPage.RelPermalink "/" -}}
-{{- $identifier := "" -}}
+{{- $result := "" -}}
 {{- range .Site.Menus.main -}}
     {{- range .Children -}}
         {{- $menuURL := trim (.URL | relLangURL) "/" -}}
-        {{- if and (eq $identifier "") (ne $menuURL "") (or (eq $curURL $menuURL) (strings.HasPrefix $curURL (printf "%s/" $menuURL))) -}}
-            {{- $identifier = .Identifier -}}
+        {{- if and (ne $menuURL "") (or (eq $curURL $menuURL) (strings.HasPrefix $curURL (printf "%s/" $menuURL))) -}}
+            {{- $result = print $result "|" .Identifier -}}
         {{- end -}}
     {{- end -}}
 {{- end -}}
-{{- $identifier -}}
+{{- $result -}}
diff --git a/hugo/layouts/partials/nav/left-nav.html b/hugo/layouts/partials/nav/left-nav.html
index 5f07103cc9d..3f76e902501 100644
--- a/hugo/layouts/partials/nav/left-nav.html
+++ b/hugo/layouts/partials/nav/left-nav.html
@@ -30,13 +30,11 @@
         <ul class="list-unstyled">
             {{ range .Children }}
                 {{/*  LEVEL 1  */}}
-                {{/* Levels 3-4 are only rendered for the top-level section containing the current page, to avoid
-                     shipping every product's full sub-nav on every page (see DOCS nav HTML size investigation).
-                     This site's main menu is defined entirely in config as plain url: strings, not via page
-                     front matter, so entries have no .Page and .IsMenuCurrent/.HasMenuCurrent (which rely on
-                     .Page identity) never match -- comparing URLs directly is what actually works here. Keep
-                     this in sync with nav/current-top-section.html, which computes the same thing for use as
-                     this partial's cache key. */}}
+                {{/* Levels 3-4 render only for the current page's top-level section, to avoid shipping every
+                     section's full sub-nav on every page. This menu is config-defined (plain url: strings, no
+                     page front matter), so entries have no .Page and .IsMenuCurrent/.HasMenuCurrent never match
+                     -- comparing URLs directly is what works. Keep in sync with nav/current-top-section.html,
+                     which computes the same matches for this partial's cache key. */}}
                 {{ $menuURL := trim (.URL | relLangURL) "/" }}
                 {{ $isCurrentTopSection := and (ne $menuURL "") (or (eq $curURL $menuURL) (strings.HasPrefix $curURL (printf "%s/" $menuURL))) }}
                 <li class="nav-top-level {{ if (not (or (in $excludeAsync .Identifier) (and (in .URL "api/") (not (in .URL "_api/")) (not (in .URL "-api/"))))) }} js-load {{ end }}
diff --git a/hugo/layouts/partials/sidenav/main-sidenav.html b/hugo/layouts/partials/sidenav/main-sidenav.html
index c960512746a..9d5cbe1646d 100644
--- a/hugo/layouts/partials/sidenav/main-sidenav.html
+++ b/hugo/layouts/partials/sidenav/main-sidenav.html
@@ -16,14 +16,8 @@
             {{ end}}
 
             <div class="sidenav-nav sidenav-nav-js-load">
-                {{/*
-                    left-nav.html's rendered HTML depends on which top-level main-menu entry the
-                    current page belongs to (see nav/current-top-section.html), not on .Section --
-                    two pages can share a Hugo content section while mapping to different (or no)
-                    top-level menu entries. Caching by .Section alone previously let a single
-                    page's render (whichever one Hugo happened to build first for that section)
-                    be served, incorrectly, for every other page in that section.
-                */}}
+                {{/* Cache key must reflect which top-level menu entries match the page, not
+                     .Section -- see nav/current-top-section.html for why. */}}
                 {{ $currentTopSection := partial "nav/current-top-section.html" . }}
                 {{ partialCached "nav/left-nav.html" . $currentTopSection .Site.Language.Lang }}
             </div>