From 02dbe81faee97c12046a250822f1c4b71acb821a Mon Sep 17 00:00:00 2001
From: shum <github.shum@liber.li>
Date: Fri, 21 Aug 2026 12:43:47 +0000
Subject: [PATCH] scripts: retry cabal update on mirror failure

---
 scripts/relay/Dockerfile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/relay/Dockerfile b/scripts/relay/Dockerfile
index ba5c735fb0..401371a0d7 100644
--- a/scripts/relay/Dockerfile
+++ b/scripts/relay/Dockerfile
@@ -19,13 +19,15 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
       llvm-12 llvm-12-dev \
     && rm -rf /var/lib/apt/lists/*
 
+# cabal update is retried: on a failed fetch cabal falls back to the mirrors in
+# Hackage's mirrors.json, which are dead, and the last one aborts the build.
 RUN curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org \
       | BOOTSTRAP_HASKELL_NONINTERACTIVE=1 \
         BOOTSTRAP_HASKELL_GHC_VERSION="${GHC}" \
         BOOTSTRAP_HASKELL_CABAL_VERSION="${CABAL}" sh \
     && ghcup set ghc "${GHC}" \
     && ghcup set cabal "${CABAL}" \
-    && cabal update
+    && { cabal update || { sleep 5; cabal update; } || { sleep 20; cabal update; }; }
 
 # Declared after the toolchain layers so that changing the ref does not rebuild
 # them. Unlike `clone --branch`, this form also accepts a commit hash.