From 314e8e49ecbfd4136463eff782190035d1b07365 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 28 Jul 2015 21:23:24 +0200
Subject: [PATCH] Remove deepOverride
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It's unused, and also a bad idea: because it recursively recomputes
every function argument and there is no sharing, you can get an
exponential (?) blowup in evaluation time. For example, evaluating
‘linuxPackages.kernel’ takes 0.09s and ~13 MiB, but evaluating
‘linuxPackages.kernel.deepOverride {}’ takes 3.6s and ~305 MiB.
---
 lib/customisation.nix | 12 ------------
 lib/deprecated.nix    |  1 -
 2 files changed, 13 deletions(-)

diff --git a/lib/customisation.nix b/lib/customisation.nix
index 91a25055df29..b3c73c39be41 100644
--- a/lib/customisation.nix
+++ b/lib/customisation.nix
@@ -49,10 +49,6 @@ rec {
        else { }));
 
 
-  # usage: (you can use override multiple times)
-  # let d = makeOverridable stdenv.mkDerivation { name = ..; buildInputs; }
-  #     noBuildInputs = d.override { buildInputs = []; }
-  #     additionalBuildInputs = d.override ( args : args // { buildInputs = args.buildInputs ++ [ additional ]; } )
   makeOverridable = f: origArgs:
     let
       ff = f origArgs;
@@ -60,24 +56,16 @@ rec {
     in
       if builtins.isAttrs ff then (ff //
         { override = newArgs: makeOverridable f (overrideWith newArgs);
-          deepOverride = newArgs:
-            makeOverridable f (lib.overrideExisting (lib.mapAttrs (deepOverrider newArgs) origArgs) newArgs);
           overrideDerivation = fdrv:
             makeOverridable (args: overrideDerivation (f args) fdrv) origArgs;
         })
       else if builtins.isFunction ff then
         { override = newArgs: makeOverridable f (overrideWith newArgs);
           __functor = self: ff;
-          deepOverride = throw "deepOverride not yet supported for functors";
           overrideDerivation = throw "overrideDerivation not yet supported for functors";
         }
       else ff;
 
-  deepOverrider = newArgs: name: x: if builtins.isAttrs x then (
-    if x ? deepOverride then (x.deepOverride newArgs) else
-    if x ? override then (x.override newArgs) else
-    x) else x;
-
 
   /* Call the package function in the file `fn' with the required
     arguments automatically.  The function is called with the
diff --git a/lib/deprecated.nix b/lib/deprecated.nix
index 54c253f2c34b..3646f9e032a1 100644
--- a/lib/deprecated.nix
+++ b/lib/deprecated.nix
@@ -29,7 +29,6 @@ rec {
                           } ));
 	withStdOverrides = base // {
 	   override = base.passthru.function;
-	   deepOverride = a : (base.passthru.function ((lib.mapAttrs (lib.deepOverrider a) base.passthru.args) // a));
 	   } ;
         in
 	withStdOverrides;