fix old nix manpages, strip priv esc

lib/manpage.ml

@@ -269,15 +269,23 @@ let classify_line line =
 (* --- section extraction ---
  * manpages are divided into sections by .SH macros. the options section
  * contains the flag definitions we want. if there's no OPTIONS section,
- * we fall back to DESCRIPTION (some simple tools put flags there). *)
+ * we fall back to DESCRIPTION (some simple tools put flags there).
+ *
+ * old-style nix manpages (nix-build, nix-env-install, etc.) split flags
+ * across multiple .SH sections with option-like names: e.g. "Options" for
+ * command-specific flags and "Common Options" for flags shared by all nix
+ * commands. collecting only the first such section misses the majority of
+ * flags, so we collect and concatenate ALL option-like sections. *)
 
 let extract_options_section lines =
   let classified = List.map classify_line lines in
-  let rec collect_until_next_sh lines acc =
+  (* collect lines until the next .SH header, returning (content, rest)
+   * where rest starts at the .SH line (or is empty if at end of file). *)
+  let rec collect_section lines acc =
     match lines with
-    | [] -> List.rev acc
-    | Macro ("SH", _) :: _ -> List.rev acc
-    | line :: rest -> collect_until_next_sh rest (line :: acc)
+    | [] -> (List.rev acc, [])
+    | Macro ("SH", _) :: _ -> (List.rev acc, lines)
+    | line :: rest -> collect_section rest (line :: acc)
   in
   let is_options_section name =
     let s = String.uppercase_ascii (String.trim name) in
@@ -286,24 +294,33 @@ let extract_options_section lines =
         try let _ = Str.search_forward (Str.regexp_string "OPTION") s 0 in true
         with Not_found -> false)
   in
-  (* First pass: look for OPTIONS section *)
-  let rec find_options = function
-    | [] -> None
+  (* Collect from ALL option-like .SH sections and concatenate them.
+   * handles the common nix pattern where "Options" and "Common Options"
+   * are separate .SH sections but both contain relevant flags.
+   *
+   * a synthetic Macro("SH","") separator is inserted between sections so
+   * that collect_desc_text (which stops on SH/SS) does not let a description
+   * from the last entry in one section bleed into the intro text of the next. *)
+  let rec find_all_options lines acc =
+    match lines with
+    | [] -> acc
     | Macro ("SH", args) :: rest when is_options_section args ->
-      Some (collect_until_next_sh rest [])
-    | _ :: rest -> find_options rest
+      let (section, remaining) = collect_section rest [] in
+      let sep = if acc = [] then [] else [Macro ("SH", "")] in
+      find_all_options remaining (acc @ sep @ section)
+    | _ :: rest -> find_all_options rest acc
   in
   (* Fallback: DESCRIPTION section *)
   let rec find_description = function
     | [] -> []
     | Macro ("SH", args) :: rest
       when String.uppercase_ascii (String.trim args) = "DESCRIPTION" ->
-      collect_until_next_sh rest []
+      fst (collect_section rest [])
     | _ :: rest -> find_description rest
   in
-  match find_options classified with
-  | Some section -> section
-  | None -> find_description classified
+  match find_all_options classified [] with
+  | [] -> find_description classified
+  | sections -> sections
 
 (* --- strategy-based entry extraction ---
  * rather than a single monolithic parser, we use multiple "strategies" that