From dfcc51def70b321ba11f985fbedeec088a8a9e88 Mon Sep 17 00:00:00 2001
From: DavHau <hsngrmpf+github@gmail.com>
Date: Tue, 11 May 2021 13:50:02 +0700
Subject: [PATCH 1/2] fetchpatch: allow empty hash

Previously, when sha256 either wasn't defined or set to an empty string
fetchpatch would error out as follows:

'''
warning: found empty hash, assuming 'sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA='
...
/nix/store/agwlk2bcfvz2ggrsbvwd7696qj55frbi-stdenv-linux/setup: line 96: /build/: Is a directory
sed: couldn't flush stdout: Broken pipe
'''

This patch makes it show fetchurl's error message instead:

'''
warning: found empty hash, assuming 'sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA='
...
error: hash mismatch in fixed-output derivation:
         specified: sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
            got:    sha256-NWGWoyEgT/ztCwbhNgGPvG+nqX4bxtFnD+wds6fklbs=
'''

This is very convenient for TOFU.

Co-Authored-By: Ivar Scholten <ivar.scholten@protonmail.com>
---
 pkgs/build-support/fetchpatch/default.nix | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/pkgs/build-support/fetchpatch/default.nix b/pkgs/build-support/fetchpatch/default.nix
index 71c0d4664983..6d45ff6340d0 100644
--- a/pkgs/build-support/fetchpatch/default.nix
+++ b/pkgs/build-support/fetchpatch/default.nix
@@ -11,13 +11,9 @@ let
 in
 { stripLen ? 0, extraPrefix ? null, excludes ? [], includes ? [], revert ? false, ... }@args:
 
-let
-  # Make base-64 encoded SRI hash filename-safe using RFC 4648 §5
-  tmpname = lib.replaceStrings [ "+" "/" "=" ] [ "-" "_" "" ] args.sha256;
-in
 fetchurl ({
   postFetch = ''
-    tmpfile="$TMPDIR/${tmpname}"
+    tmpfile="$TMPDIR/patch"
     if [ ! -s "$out" ]; then
       echo "error: Fetched patch file '$out' is empty!" 1>&2
       exit 1

From ac728c1e96d40e740f79da1165e30b727030e954 Mon Sep 17 00:00:00 2001
From: DavHau <hsngrmpf+github@gmail.com>
Date: Mon, 20 Dec 2021 05:09:32 +0100
Subject: [PATCH 2/2] fetchpatch: Clean up

Co-Authored-By: Ivar Scholten <ivar.scholten@protonmail.com>
---
 pkgs/build-support/fetchpatch/default.nix | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/pkgs/build-support/fetchpatch/default.nix b/pkgs/build-support/fetchpatch/default.nix
index 6d45ff6340d0..740baa8cff5f 100644
--- a/pkgs/build-support/fetchpatch/default.nix
+++ b/pkgs/build-support/fetchpatch/default.nix
@@ -9,15 +9,24 @@ let
   # 0.3.4 would change hashes: https://github.com/NixOS/nixpkgs/issues/25154
   patchutils = buildPackages.patchutils_0_3_3;
 in
-{ stripLen ? 0, extraPrefix ? null, excludes ? [], includes ? [], revert ? false, ... }@args:
+{ stripLen ? 0
+, extraPrefix ? null
+, excludes ? []
+, includes ? []
+, revert ? false
+, postFetch ? ""
+, ...
+}@args:
 
 fetchurl ({
   postFetch = ''
     tmpfile="$TMPDIR/patch"
+
     if [ ! -s "$out" ]; then
       echo "error: Fetched patch file '$out' is empty!" 1>&2
       exit 1
     fi
+
     "${patchutils}/bin/lsdiff" "$out" \
       | sort -u | sed -e 's/[*?]/\\&/g' \
       | xargs -I{} \
@@ -29,6 +38,7 @@ fetchurl ({
            --addnewprefix=b/${extraPrefix} \
         ''} \
         --clean "$out" > "$tmpfile"
+
     if [ ! -s "$tmpfile" ]; then
       echo "error: Normalized patch '$tmpfile' is empty (while the fetched file was not)!" 1>&2
       echo "Did you maybe fetch a HTML representation of a patch instead of a raw patch?" 1>&2
@@ -36,6 +46,7 @@ fetchurl ({
       cat "$out" 1>&2
       exit 1
     fi
+
     ${patchutils}/bin/filterdiff \
       -p1 \
       ${builtins.toString (builtins.map (x: "-x ${lib.escapeShellArg x}") excludes)} \
@@ -52,6 +63,6 @@ fetchurl ({
   '' + lib.optionalString revert ''
     ${patchutils}/bin/interdiff "$out" /dev/null > "$tmpfile"
     mv "$tmpfile" "$out"
-  '' + (args.postFetch or "");
+  '' + postFetch;
   meta.broken = excludes != [] && includes != [];
 } // builtins.removeAttrs args ["stripLen" "extraPrefix" "excludes" "includes" "revert" "postFetch"])