nixpkgs/pkgs/development/tools/build-managers/rebar3/hermetic-rebar3.patch

diff a/src/rebar3.erl b/src/rebar3.erl
index c1a1ae4..1bf1ea0 100644
--- a/src/rebar3.erl
+++ b/src/rebar3.erl
@@ -294,9 +294,11 @@ start_and_load_apps(Caller) ->
     ensure_running(crypto, Caller),
     ensure_running(asn1, Caller),
     ensure_running(public_key, Caller),
-    ensure_running(ssl, Caller),
-    inets:start(),
-    inets:start(httpc, [{profile, rebar}]).
+    ensure_running(ssl, Caller).
+%%  Removed due to the hermicity requirements of Nix
+%%
+%%    inets:start(),
+%%    inets:start(httpc, [{profile, rebar}]).

 ensure_running(App, Caller) ->
     case application:start(App) of
diff a/src/rebar_hermicity.erl b/src/rebar_hermicity.erl
new file mode 100644
index 0000000..d814e2a
--- /dev/null
+++ b/src/rebar_hermicity.erl
@@ -0,0 +1,42 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2016 Eric Merritt (eric@merritt.tech)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_hermicity).
+
+-export([request/5]).
+
+-include("rebar.hrl").
+
+%% ====================================================================
+%% Public API
+%% ====================================================================
+
+request(Method, {Url, _Headers}, _HTTPOptions, _Options, _Profile) ->
+    ?ERROR("A request is being made that violates Nix hermicity "
+           "This request has been stopped. Details of the request "
+           "are as follows:", []),
+    ?ERROR("Requesnt: ~p ~s", [Method, Url]),
+    erlang:halt(1).
diff a/src/rebar_pkg_resource.erl b/src/rebar_pkg_resource.erl
index ec7e09d..03be343 100644
--- a/src/rebar_pkg_resource.erl
+++ b/src/rebar_pkg_resource.erl
@@ -104,7 +104,7 @@ make_vsn(_) ->
     {error, "Replacing version of type pkg not supported."}.

 request(Url, ETag) ->
-    case httpc:request(get, {Url, [{"if-none-match", ETag} || ETag =/= false]++[{"User-Agent", rebar_utils:user_agent()}]},
+    case rebar_hermicity:request(get, {Url, [{"if-none-match", ETag} || ETag =/= false]++[{"User-Agent", rebar_utils:user_agent()}]},
                        [{ssl, ssl_opts(Url)}, {relaxed, true}],
                        [{body_format, binary}],
                        rebar) of
diff a/src/rebar_prv_update.erl b/src/rebar_prv_update.erl
index 5e1e253..ea25b9e 100644
--- a/src/rebar_prv_update.erl
+++ b/src/rebar_prv_update.erl
@@ -52,7 +52,7 @@ do(State) ->
                 case rebar_utils:url_append_path(CDN, ?REMOTE_REGISTRY_FILE) of
                     {ok, Url} ->
                         ?DEBUG("Fetching registry from ~p", [Url]),
-                        case httpc:request(get, {Url, [{"User-Agent", rebar_utils:user_agent()}]},
+                        case rebar_hermicity:request(get, {Url, [{"User-Agent", rebar_utils:user_agent()}]},
                                            [], [{stream, TmpFile}, {sync, true}],
                                            rebar) of
                             {ok, saved_to_file} ->