From 2632c6139d9b1a7ca7be4da1924e7a78edfa452c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Ber=C3=A1nek?= <berykubik@gmail.com>
Date: Tue, 23 Apr 2024 08:59:45 +0200
Subject: [PATCH] Fix empty job matrix

---
 .github/workflows/ci.yml     | 1 +
 src/ci/github-actions/ci.yml | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 670a2854fed..872b671b031 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -63,6 +63,7 @@ jobs:
     strategy:
       matrix:
         include: "${{ fromJSON(needs.calculate_matrix.outputs.jobs) }}"
+    if: "fromJSON(needs.calculate_matrix.outputs.jobs)[0] != null"
     defaults:
       run:
         shell: "${{ contains(matrix.os, 'windows') && 'msys2 {0}' || 'bash' }}"
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index 1efdd7e22e9..19d6b517552 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -373,6 +373,14 @@ jobs:
       matrix:
         # Check the `calculate_matrix` job to see how is the matrix defined.
         include: ${{ fromJSON(needs.calculate_matrix.outputs.jobs) }}
+    # GitHub Actions fails the workflow if an empty list of jobs is provided to
+    # the workflow, so we need to skip this job if nothing was produced by
+    # the Python script.
+    #
+    # Unfortunately checking whether a list is empty is not possible in a nice
+    # way due to GitHub Actions expressions limits.
+    # This hack is taken from https://github.com/ferrocene/ferrocene/blob/d43edc6b7697cf1719ec1c17c54904ab94825763/.github/workflows/release.yml#L75-L82
+    if: fromJSON(needs.calculate_matrix.outputs.jobs)[0] != null
 
   master:
     name: master