lib/fetchers.nix: factor out impure proxy vars (#18702)

Apparently everyone just copied those variables, instead of creating a
library constant for them. Some even removed the comment. -.-

lib/default.nix

@@ -31,6 +31,7 @@ let
 
   # domain-specific
   sandbox = import ./sandbox.nix;
+  fetchers = import ./fetchers.nix;
 
 in
   { inherit trivial
@@ -39,7 +40,7 @@ in
             modules options types
             licenses platforms systems
             debug misc
-            sandbox;
+            sandbox fetchers;
   }
   # !!! don't include everything at top-level; perhaps only the most
   # commonly used functions.

lib/fetchers.nix

@@ -0,0 +1,12 @@
+# snippets that can be shared by mutliple fetchers (pkgs/build-support)
+{
+
+  proxyImpureEnvVars = [
+    # We borrow these environment variables from the caller to allow
+    # easy proxy configuration.  This is impure, but a fixed-output
+    # derivation like fetchurl is allowed to do so since its result is
+    # by definition pure.
+    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
+  ];
+
+}

pkgs/applications/networking/browsers/chromium/update.nix

@@ -157,9 +157,7 @@ in rec {
           fi
         '';
 
-        impureEnvVars = [
+        impureEnvVars = lib.fetchers.proxyImpureEnvVars;
-          "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-        ];
       };
 
     in {

pkgs/applications/networking/cluster/chronos/chronos-deps.nix

@@ -10,9 +10,5 @@ stdenv.mkDerivation {
 
   buildInputs = [ curl ];
 
-  # We borrow these environment variables from the caller to allow
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-  # easy proxy configuration.  This is impure, but a fixed-output
-  # derivation like fetchurl is allowed to do so since its result is
-  # by definition pure.
-  impureEnvVars = ["http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"];
 }

pkgs/applications/networking/cluster/mesos/mesos-deps.nix

@@ -10,9 +10,5 @@ stdenv.mkDerivation {
 
   buildInputs = [ curl ];
 
-  # We borrow these environment variables from the caller to allow
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-  # easy proxy configuration.  This is impure, but a fixed-output
-  # derivation like fetchurl is allowed to do so since its result is
-  # by definition pure.
-  impureEnvVars = ["http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"];
 }

pkgs/build-support/docker/pull.nix

@@ -26,17 +26,11 @@ let layer = stdenv.mkDerivation {
   outputHash = sha256;
   outputHashMode = "recursive";
 
-  impureEnvVars = [
+  impureEnvVars = lib.fetchers.proxyImpureEnvVars ++ [
-    # We borrow these environment variables from the caller to allow
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-
     # This variable allows the user to pass additional options to curl
     "NIX_CURL_FLAGS"
   ];
-  
+
   # Doing the download on a remote machine just duplicates network
   # traffic, so don't do that.
   preferLocalBuild = true;

pkgs/build-support/fetchadc/default.nix

@@ -1,15 +1,5 @@
 { stdenv, curl, adc_user, adc_pass }:
 
-let
-  impureEnvVars = [
-    # We borrow these environment variables from the caller to allow
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-  ];
-in
-
 { # Path to fetch.
   path
 

pkgs/build-support/fetchegg/default.nix

@@ -17,12 +17,6 @@ stdenv.mkDerivation {
 
   eggName = name;
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-    # We borrow these environment variables from the caller to allow
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-  ];
 }
 

pkgs/build-support/fetchgit/default.nix

@@ -56,13 +56,9 @@ stdenv.mkDerivation {
 
   GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars ++ [
-    # We borrow these environment variables from the caller to allow
+    "GIT_PROXY_COMMAND" "SOCKS_SERVER"
-    # easy proxy configuration.  This is impure, but a fixed-output
+  ];
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy" "GIT_PROXY_COMMAND" "SOCKS_SERVER"
-    ];
 
   preferLocalBuild = true;
 }

pkgs/build-support/fetchhg/default.nix

@@ -6,9 +6,7 @@ stdenv.mkDerivation {
   builder = ./builder.sh;
   buildInputs = [mercurial];
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-  ];
 
   # Nix <= 0.7 compatibility.
   id = md5;

pkgs/build-support/fetchmtn/default.nix

@@ -19,12 +19,7 @@ stdenv.mkDerivation {
   dbs = defaultDBMirrors ++ dbs;
   inherit branch cacheDB name selector;
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-    # We borrow these environment variables from the caller to allow
+
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-    ];
 }
 

pkgs/build-support/fetchsvn/default.nix

@@ -33,13 +33,6 @@ stdenv.mkDerivation {
   
   inherit url rev sshSupport openssh ignoreExternals;
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
-    # We borrow these environment variables from the caller to allow
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-    ];
-
   preferLocalBuild = true;
 }

pkgs/build-support/fetchurl/default.nix

@@ -20,13 +20,7 @@ let
   # "gnu", etc.).
   sites = builtins.attrNames mirrors;
 
-  impureEnvVars = [
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars ++ [
-    # We borrow these environment variables from the caller to allow
-    # easy proxy configuration.  This is impure, but a fixed-output
-    # derivation like fetchurl is allowed to do so since its result is
-    # by definition pure.
-    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
-
     # This variable allows the user to pass additional options to curl
     "NIX_CURL_FLAGS"
 

pkgs/build-support/rust/fetchcargo.nix

@@ -20,6 +20,6 @@ stdenv.mkDerivation {
   outputHashMode = "recursive";
   outputHash = sha256;
 
-  impureEnvVars = [ "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy" ];
+  impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
   preferLocalBuild = true;
 }