Manual: Don't depend on the absolute path of modules

This ensures that the manual has the same store path regardless of the
directory in which Nixpkgs is stored, and thus can be fetched from the
channel.

nixos/doc/manual/default.nix

@@ -7,9 +7,23 @@ with pkgs.lib;
 
 let
 
-  options' = filter (x: x.visible && !x.internal) (optionAttrSetToDocList options);
-
-  optionsXML = builtins.toFile "options.xml" (builtins.unsafeDiscardStringContext (builtins.toXML options'));
+  # Remove invisible and internal options.
+  options' = filter (opt: opt.visible && !opt.internal) (optionAttrSetToDocList options);
+
+  # Clean up declaration sites to not refer to the NixOS source tree.
+  options'' = flip map options' (opt: opt // {
+    declarations = map (fn: stripPrefix fn) opt.declarations;
+  });
+
+  prefix = toString pkgs.path;
+  
+  stripPrefix = fn:
+    if substring 0 (stringLength prefix) fn == prefix then
+      substring (add (stringLength prefix) 1) 1000 fn
+    else
+      fn;
+
+  optionsXML = builtins.toFile "options.xml" (builtins.unsafeDiscardStringContext (builtins.toXML options''));
 
   optionsDocBook = pkgs.runCommand "options-db.xml" {} ''
     ${pkgs.libxslt}/bin/xsltproc \

nixos/doc/manual/options-to-docbook.xsl

@@ -155,8 +155,15 @@
           repository (if it’s a module and we have a revision number),
           or to the local filesystem. -->
           <xsl:choose>
-            <xsl:when test="$revision != 'local' and contains(@value, '/modules/')">
-              <xsl:attribute name="xlink:href">https://github.com/NixOS/nixos/blob/<xsl:value-of select="$revision"/>/modules/<xsl:value-of select="substring-after(@value, '/modules/')"/></xsl:attribute>
+            <xsl:when test="not(starts-with(@value, '/'))">
+              <xsl:choose>
+                <xsl:when test="$revision = 'local'">
+                  <xsl:attribute name="xlink:href">https://github.com/NixOS/nixpkgs/blob/master/<xsl:value-of select="@value"/></xsl:attribute>
+                </xsl:when>
+                <xsl:otherwise>
+                  <xsl:attribute name="xlink:href">https://github.com/NixOS/nixpkgs/blob/<xsl:value-of select="$revision"/>/<xsl:value-of select="@value"/></xsl:attribute>
+                </xsl:otherwise>
+              </xsl:choose>
             </xsl:when>
             <xsl:when test="$revision != 'local' and contains(@value, 'nixops') and contains(@value, '/nix/')">
               <xsl:attribute name="xlink:href">https://github.com/NixOS/nixops/blob/<xsl:value-of select="$revision"/>/nix/<xsl:value-of select="substring-after(@value, '/nix/')"/></xsl:attribute>
@@ -169,8 +176,8 @@
           /nix/store/<hash> prefix by the default location of nixos
           sources. -->
           <xsl:choose>
-            <xsl:when test="contains(@value, '/modules/')">
-              &lt;nixos/modules/<xsl:value-of select="substring-after(@value, '/modules/')"/>&gt;
+            <xsl:when test="not(starts-with(@value, '/'))">
+              &lt;nixpkgs/<xsl:value-of select="@value"/>&gt;
             </xsl:when>
             <xsl:when test="contains(@value, 'nixops') and contains(@value, '/nix/')">
               &lt;nixops/<xsl:value-of select="substring-after(@value, '/nix/')"/>&gt;