From 5a1bc70ec063b414694b31a1bf39deeed008e688 Mon Sep 17 00:00:00 2001
From: Jan Tojnar <jtojnar@gmail.com>
Date: Thu, 30 Jan 2020 21:08:55 +0100
Subject: [PATCH] common-updater-scripts: Support SRI-style hash
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Some fetcher functions support SRI-style `hash` attribute in addition to legacy type-specific attributes. When `hash` is used `outputHashAlgo` is null so let’s complain when SRI-style hash value was not detected.

Such attributes match the form ${type}${separator}${hash}: True SRI uses dash as a separator and only supports base64, whereas Nix’s SRI-style format uses a colon and supports all the same encodings like regular hashes (16/32/64).

To keep this program reasonably simple, we will upgrade Nix’s SRI-like format to pure SRI instead of preserving it.
---
 .../scripts/update-source-version             | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/pkgs/common-updater/scripts/update-source-version b/pkgs/common-updater/scripts/update-source-version
index a0077ee9f01d..77245a1b1aa5 100755
--- a/pkgs/common-updater/scripts/update-source-version
+++ b/pkgs/common-updater/scripts/update-source-version
@@ -132,7 +132,19 @@ if [ -n "$newUrl" ]; then
     fi
 fi
 
+if [[ "$oldHash" =~ ^(sha256|sha512)[:-] ]]; then
+    # Handle the possible SRI-style hash attribute (in the form ${type}${separator}${hash})
+    # True SRI uses dash as a separator and only supports base64, whereas Nix’s SRI-style format uses a colon and supports all the same encodings like regular hashes (16/32/64).
+    # To keep this program reasonably simple, we will upgrade Nix’s format to SRI.
+    oldHashAlgo="${BASH_REMATCH[1]}"
+    sri=true
+elif [[ "$oldHashAlgo" = "null" ]]; then
+    # Some fetcher functions support SRI-style `hash` attribute in addition to legacy type-specific attributes. When `hash` is used `outputHashAlgo` is null so let’s complain when SRI-style hash value was not detected.
+    die "Unable to figure out hashing scheme from '$oldHash' in '$attr'!"
+fi
+
 case "$oldHashAlgo" in
+    # Lengths of hex-encoded hashes
     sha256) hashLength=64 ;;
     sha512) hashLength=128 ;;
     *) die "Unhandled hash algorithm '$oldHashAlgo' in '$attr'!" ;;
@@ -141,6 +153,12 @@ esac
 # Make a temporary all-zeroes hash of $hashLength characters
 tempHash=$(printf '%0*d' "$hashLength" 0)
 
+if [[ -n "$sri" ]]; then
+    # SRI hashes only support base64
+    # SRI hashes need to declare the hash type as part of the hash
+    tempHash="$(nix to-sri --type "$oldHashAlgo" "$tempHash")"
+fi
+
 sed -i "$nixFile" -re "s|\"$oldHash\"|\"$tempHash\"|"
 if cmp -s "$nixFile" "$nixFile.bak"; then
     die "Failed to replace source hash of '$attr' to a temporary hash!"
@@ -153,6 +171,11 @@ if [ -z "$newHash" ]; then
     newHash=$(egrep -v "killing process|dependencies couldn't be built|wanted: " "$attr.fetchlog" | tail -n2 | sed "s~output path .* has .* hash ‘\(.*\)’ when .* was expected\|fixed-output derivation produced path '.*' with .* hash '\(.*\)' instead of the expected hash '.*'\|  got:    .*:\(.*\)~\1\2\3~" | head -n1)
 fi
 
+if [[ -n "$sri" ]]; then
+    # nix-build preserves the hashing scheme so we can just convert the result to SRI using the old type
+    newHash="$(nix to-sri --type "$oldHashAlgo" "$newHash")"
+fi
+
 if [ -z "$newHash" ]; then
     cat "$attr.fetchlog" >&2
     die "Couldn't figure out new hash of '$attr.src'!"