Remove references to the nixpkgs-channels repo

Channel branches are now provided in the nixpkgs repo.

Issue #71176.

README.md

@@ -51,9 +51,7 @@ system, [Hydra](https://hydra.nixos.org/).
 Artifacts successfully built with Hydra are published to cache at
 https://cache.nixos.org/. When successful build and test criteria are
 met, the Nixpkgs expressions are distributed via [Nix
-channels](https://nixos.org/nix/manual/#sec-channels). The channels
-are provided via a read-only mirror of the Nixpkgs repository called
-[nixpkgs-channels](https://github.com/NixOS/nixpkgs-channels).
+channels](https://nixos.org/nix/manual/#sec-channels).
 
 # Contributing
 

doc/introduction.chapter.md

@@ -47,5 +47,5 @@ which also builds binary packages from the Nix expressions in Nixpkgs for
 The binaries are made available via a [binary cache](https://cache.nixos.org).
 
 The current Nix expressions of the channels are available in the
-[`nixpkgs-channels`](https://github.com/NixOS/nixpkgs-channels) repository,
-which has branches corresponding to the available channels.
+[`nixpkgs`](https://github.com/NixOS/nixpkgs) repository in branches
+that correspond to the channel names (e.g. `nixos-19.09-small`).

doc/reviewing-contributions.xml

@@ -115,19 +115,12 @@
       <para>
        It is possible to rebase the changes on nixos-unstable or nixpkgs-unstable for easier review by running the following commands from a nixpkgs clone.
 <screen>
-<prompt>$ </prompt>git remote add channels https://github.com/NixOS/nixpkgs-channels.git <co
-  xml:id='reviewing-rebase-1' />
-<prompt>$ </prompt>git fetch channels nixos-unstable <co xml:id='reviewing-rebase-2' />
+<prompt>$ </prompt>git fetch origin nixos-unstable <co xml:id='reviewing-rebase-2' />
 <prompt>$ </prompt>git fetch origin pull/PRNUMBER/head <co xml:id='reviewing-rebase-3' />
 <prompt>$ </prompt>git rebase --onto nixos-unstable BASEBRANCH FETCH_HEAD <co
   xml:id='reviewing-rebase-4' />
 </screen>
        <calloutlist>
-        <callout arearefs='reviewing-rebase-1'>
-         <para>
-          This should be done only once to be able to fetch channel branches from the nixpkgs-channels repository.
-         </para>
-        </callout>
         <callout arearefs='reviewing-rebase-2'>
          <para>
           Fetching the nixos-unstable branch.

nixos/doc/manual/development/sources.xml

@@ -13,17 +13,16 @@
 <screen>
 <prompt>$ </prompt>git clone https://github.com/NixOS/nixpkgs
 <prompt>$ </prompt>cd nixpkgs
-<prompt>$ </prompt>git remote add channels https://github.com/NixOS/nixpkgs-channels
-<prompt>$ </prompt>git remote update channels
+<prompt>$ </prompt>git remote update origin
 </screen>
   This will check out the latest Nixpkgs sources to
   <filename>./nixpkgs</filename> the NixOS sources to
   <filename>./nixpkgs/nixos</filename>. (The NixOS source tree lives in a
-  subdirectory of the Nixpkgs repository.) The remote
-  <literal>channels</literal> refers to a read-only repository that tracks the
-  Nixpkgs/NixOS channels (see <xref linkend="sec-upgrading"/> for more
+  subdirectory of the Nixpkgs repository.) The
+  <literal>nixpkgs</literal> repository has branches that correspond
+  to each Nixpkgs/NixOS channel (see <xref linkend="sec-upgrading"/> for more
   information about channels). Thus, the Git branch
-  <literal>channels/nixos-17.03</literal> will contain the latest built and
+  <literal>origin/nixos-17.03</literal> will contain the latest built and
   tested version available in the <literal>nixos-17.03</literal> channel.
  </para>
  <para>
@@ -40,15 +39,15 @@
   Or, to base your local branch on the latest version available in a NixOS
   channel:
 <screen>
-<prompt>$ </prompt>git remote update channels
-<prompt>$ </prompt>git checkout -b local channels/nixos-17.03
+<prompt>$ </prompt>git remote update origin
+<prompt>$ </prompt>git checkout -b local origin/nixos-17.03
 </screen>
   (Replace <literal>nixos-17.03</literal> with the name of the channel you want
   to use.) You can use <command>git merge</command> or <command>git
   rebase</command> to keep your local branch in sync with the channel, e.g.
 <screen>
-<prompt>$ </prompt>git remote update channels
-<prompt>$ </prompt>git merge channels/nixos-17.03
+<prompt>$ </prompt>git remote update origin
+<prompt>$ </prompt>git merge origin/nixos-17.03
 </screen>
   You can use <command>git cherry-pick</command> to copy commits from your
   local branch to the upstream branch.