From e8bfc5bb69529bffe777eef921214fe90a37dd66 Mon Sep 17 00:00:00 2001
From: Tomas Janousek <tomi@nomi.cz>
Date: Sun, 23 May 2021 23:41:02 +0100
Subject: [PATCH] ci: Prevent ~/.stack/pantry cache from being empty

When building with an LTS version that has exactly the dependencies we
need (X11-1.9.2), stack doesn't need to download the Hackage index. If
GitHub Actions cache locking chooses this job as the one that writes the
cache, then the "stack-pantry-Linux" cache entry stays empty, possibly
forever.

Force Hackage index update to prevent this from happening.

Related: https://github.com/xmonad/xmonad-contrib/commit/d1a4820b55931055f8eccae5dc306d58dea21d93
---
 .github/workflows/stack.yml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.github/workflows/stack.yml b/.github/workflows/stack.yml
index 7958791..73b6498 100644
--- a/.github/workflows/stack.yml
+++ b/.github/workflows/stack.yml
@@ -66,6 +66,12 @@ jobs:
             stack-${{ runner.os }}-${{ matrix.resolver }}-${{ hashFiles('stack.yaml') }}-
             stack-${{ runner.os }}-${{ matrix.resolver }}-
 
+      - name: Update hackage index
+        # always update index to prevent the shared ~/.stack/pantry cache from being empty
+        run: |
+          set -ex
+          stack update
+
       - name: Build and test
         run: |
           set -ex