Fix URL remapping for page references

Page links were not being remapped because the remap prefix check
only matched against the directory path. For modules, the module name
is part of the directory (e.g., prefix/otherpkg/Otherlib/index.html),
so it matched. But for pages, the page name is in the filename
(e.g., prefix/otherpkg/otherpage.html), leaving only prefix/otherpkg
in the directory - which didn't match prefix/otherpkg/ due to the
trailing slash.

Fix by including the filename in the path used for prefix matching.
Also normalize remap entries at config creation time (ensure trailing
slashes) rather than on each lookup.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: jonludlam

src/html/config.ml

@@ -15,9 +15,18 @@ type t = {
   home_breadcrumb : string option;
 }
 
+let ensure_trailing_slash s =
+  if Astring.String.is_suffix ~affix:"/" s then s else s ^ "/"
+
 let v ?(search_result = false) ?theme_uri ?support_uri ?(search_uris = [])
     ~semantic_uris ~indent ~flat ~open_details ~as_json ~remap ?home_breadcrumb
     () =
+  let remap =
+    List.map
+      (fun (prefix, replacement) ->
+        (ensure_trailing_slash prefix, ensure_trailing_slash replacement))
+      remap
+  in
   {
     semantic_uris;
     indent;

src/html/link.ml

@@ -11,11 +11,11 @@ module Path = struct
 
   let is_leaf_page url = url.Url.Path.kind = `LeafPage
 
-  let remap config f =
-    let l = String.concat "/" f in
+  let remap config dir file =
+    let path = String.concat "/" dir ^ "/" ^ file in
     let remaps =
       List.filter
-        (fun (prefix, _replacement) -> Astring.String.is_prefix ~affix:prefix l)
+        (fun (prefix, _) -> Astring.String.is_prefix ~affix:prefix path)
         (Config.remap config)
     in
     let remaps =
@@ -26,9 +26,11 @@ module Path = struct
     match remaps with
     | [] -> None
     | (prefix, replacement) :: _ ->
-        let len = String.length prefix in
-        let l = String.sub l len (String.length l - len) in
-        Some (replacement ^ l)
+        let remainder =
+          String.sub path (String.length prefix)
+            (String.length path - String.length prefix)
+        in
+        Some (replacement ^ remainder)
 
   let get_dir_and_file ~config url =
     let l = Url.Path.to_list url in
@@ -52,9 +54,9 @@ module Path = struct
 
   let for_linking ~config url =
     let dir, file = get_dir_and_file ~config url in
-    match remap config dir with
+    match remap config dir file with
     | None -> Relative (dir, file)
-    | Some x -> Absolute (x ^ "/" ^ file)
+    | Some url -> Absolute url
 
   let as_filename ~config (url : Url.Path.t) =
     let dir, file = get_dir_and_file ~config url in

test/integration/remap.t/otherpage.mld

@@ -0,0 +1,3 @@
+{0 Other Page}
+
+This is documentation from the other package.

test/integration/remap.t/run.t

@@ -1,8 +1,10 @@
   $ ocamlc -c -bin-annot otherlib.mli
   $ ocamlc -c -bin-annot test.mli
   $ odoc compile --parent-id prefix/otherpkg --output-dir _odoc otherlib.cmti
+  $ odoc compile --parent-id prefix/otherpkg --output-dir _odoc otherpage.mld
   $ odoc compile --parent-id prefix/mypkg --output-dir _odoc test.cmti
   $ odoc link _odoc/prefix/otherpkg/otherlib.odoc
+  $ odoc link _odoc/prefix/otherpkg/page-otherpage.odoc
   $ odoc link -I _odoc/prefix/otherpkg _odoc/prefix/mypkg/test.odoc
 
 We should be able to remap the links to one of the packages:
@@ -14,6 +16,12 @@ We should be able to remap the links to one of the packages:
   _html/prefix/mypkg/Test/index.html:       <a href="../../otherpkg/Otherlib/index.html#type-t">Otherlib.t</a>
   _html2/prefix/mypkg/Test/index.html:        href="https://mysite.org/p/otherpkg/1.2.3/Otherlib/index.html#type-t">
 
+Page links should also be remapped:
+
+  $ grep otherpage.html _html/prefix/mypkg/Test/index.html _html2/prefix/mypkg/Test/index.html
+  _html/prefix/mypkg/Test/index.html:    <a href="../../otherpkg/otherpage.html"><code>otherpage</code></a>
+  _html2/prefix/mypkg/Test/index.html:    <a href="https://mysite.org/p/otherpkg/1.2.3/otherpage.html">
+
 This shouldn't stop us from outputting the remapped package though, and the following should complete without error
 
   $ odoc html-generate -o _html3 _odoc/prefix/otherpkg/otherlib.odocl -R prefix/otherpkg/:https://mysite.org/p/otherpkg/1.2.3/

test/integration/remap.t/test.mli

@@ -1,2 +1,4 @@
 type t = Otherlib.t
 
+(** See the {!page-otherpage} for more info. *)
+