From 56595dd7071ac2e63a878387c1a15d5dfe34851c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 11:48:57 +0100
Subject: [PATCH 01/17] Move `crystal_bootstrap_version` to matrix

---
 .github/workflows/linux.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index d30d592b6cd1..26035bd9b3fc 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -27,11 +27,11 @@ jobs:
       fail-fast: false
       matrix:
         flags: [""]
+        crystal_bootstrap_version: ["1.18.2"] # LATEST RELEASE
         include:
           # libffi is only available starting from the 1.2.2 build images
           - crystal_bootstrap_version: 1.0.0
             flags: "FLAGS=-Dwithout_ffi USE_PCRE1=true"
-          - crystal_bootstrap_version: 1.18.2 # LATEST RELEASE
     steps:
       - name: Download Crystal source
         uses: actions/checkout@v5

From 231f846b820e62711ae82a66eaacb6b97f9fba1a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:02:36 +0100
Subject: [PATCH 02/17] Refactor `flags` into `env`

---
 .github/workflows/linux.yml | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 26035bd9b3fc..dae133923fa6 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -26,12 +26,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        flags: [""]
+        env: [{}]
         crystal_bootstrap_version: ["1.18.2"] # LATEST RELEASE
         include:
-          # libffi is only available starting from the 1.2.2 build images
           - crystal_bootstrap_version: 1.0.0
-            flags: "FLAGS=-Dwithout_ffi USE_PCRE1=true"
+            env:
+              # libffi is only available starting from the 1.2.2 build images
+              FLAGS: "-Dwithout_ffi"
+              # pcre2 is only available starting from the 1.8.0 build images
+              USE_PCRE1: true
     steps:
       - name: Download Crystal source
         uses: actions/checkout@v5
@@ -45,7 +48,8 @@ jobs:
         run: bin/ci prepare_build
 
       - name: Test
-        run: ${{ matrix.flags }} bin/ci build
+        run: bin/ci build
+        env: ${{ matrix.env }}
 
   x86_64-musl-test:
     env:

From f5b412e30e110ff605c267e25586c37e7bc5dda3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:09:29 +0100
Subject: [PATCH 03/17] Merge `crystal_bootstrap_version` into `env`

---
 .github/workflows/linux.yml | 6 ++----
 bin/ci                      | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index dae133923fa6..df7aeb2d06ed 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -21,16 +21,14 @@ jobs:
     env:
       ARCH: x86_64
       ARCH_CMD: linux64
-      DOCKER_TEST_PREFIX: crystallang/crystal:${{ matrix.crystal_bootstrap_version }}
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
         env: [{}]
-        crystal_bootstrap_version: ["1.18.2"] # LATEST RELEASE
         include:
-          - crystal_bootstrap_version: 1.0.0
-            env:
+          - env:
+              CRYSTAL_BOOTSTRAP_VERSION: 1.0.0
               # libffi is only available starting from the 1.2.2 build images
               FLAGS: "-Dwithout_ffi"
               # pcre2 is only available starting from the 1.8.0 build images
diff --git a/bin/ci b/bin/ci
index fabeae18cbab..a47600b5c952 100755
--- a/bin/ci
+++ b/bin/ci
@@ -189,7 +189,7 @@ with_build_env() {
 
   on_linux verify_linux_environment
 
-  export DOCKER_TEST_PREFIX="${DOCKER_TEST_PREFIX:=crystallang/crystal:1.18.2}"
+  export DOCKER_TEST_PREFIX="${DOCKER_TEST_PREFIX:="crystallang/crystal:${CRYSTAL_BOOTSTRAP_VERSION:-1.18.2}"}"
 
   case $ARCH in
     x86_64)

From 266517bbd28543807df374b69d534e028a3b79a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:05:08 +0100
Subject: [PATCH 04/17] Add flags to matrix

---
 .github/workflows/linux.yml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index df7aeb2d06ed..9ec07e92e954 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -25,7 +25,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        env: [{}]
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
         include:
           - env:
               CRYSTAL_BOOTSTRAP_VERSION: 1.0.0

From ce669bd62aea0a5d576ca9686ca15df8c5b7b187 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:13:22 +0100
Subject: [PATCH 05/17] Add matrix to `musl-test`

---
 .github/workflows/linux.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 9ec07e92e954..f3778a3e3e00 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -58,6 +58,14 @@ jobs:
       ARCH: x86_64-musl
       ARCH_CMD: linux64
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
     steps:
       - name: Download Crystal source
         uses: actions/checkout@v5
@@ -72,6 +80,7 @@ jobs:
 
       - name: Test
         run: bin/ci build
+        env: ${{ matrix.env }}
 
   x86_64-gnu-test-preview_mt:
     env:

From 44fa8322078096981a9d96724735bfb93aa10ae0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:17:13 +0100
Subject: [PATCH 06/17] Drop arch

---
 .github/workflows/macos.yml | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 191e66ec988d..0fabf167de39 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -15,16 +15,9 @@ env:
 jobs:
   darwin-test:
     runs-on: ${{ matrix.runs-on }}
-    name: "${{ matrix.runs-on }} (${{ matrix.arch }})"
     strategy:
       matrix:
-        include:
-        - runs-on: macos-15-intel
-          arch: x86_64-darwin
-        - runs-on: macos-14
-          arch: aarch64-darwin
-        - runs-on: macos-15
-          arch: aarch64-darwin
+        runs-on: [macos-15-intel, macos-14, macos-15]
       fail-fast: false
     steps:
       - name: Download Crystal source

From cd7c047c151b32d88001637b1d0efa6d3a66632e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:18:10 +0100
Subject: [PATCH 07/17] Drop `macos-14`

---
 .github/workflows/macos.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 0fabf167de39..be26a5978b9b 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     strategy:
       matrix:
-        runs-on: [macos-15-intel, macos-14, macos-15]
+        runs-on: [macos-15-intel, macos-15]
       fail-fast: false
     steps:
       - name: Download Crystal source

From cb034d75ed21190765255acc53f6e67f6779ac21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:18:23 +0100
Subject: [PATCH 08/17] Add `env` to macos tests

---
 .github/workflows/macos.yml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index be26a5978b9b..f0f43f80e558 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -17,6 +17,11 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     strategy:
       matrix:
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
         runs-on: [macos-15-intel, macos-15]
       fail-fast: false
     steps:
@@ -43,6 +48,8 @@ jobs:
 
       - name: Test
         run: bin/ci build
+        env: ${{ matrix.env }}
 
       - name: Test interpreter
         run: bin/ci with_build_env 'make interpreter_spec'
+        env: ${{ matrix.env }}

From 0a9ac7ed08dc20198682f71ca06e605a5ab3a125 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:19:44 +0100
Subject: [PATCH 09/17] Add `env` to smoke-test

---
 .github/workflows/smoke.yml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index c16cb6101cb1..364f23cfc618 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -64,6 +64,11 @@ jobs:
       max-parallel: 2
       fail-fast: false
       matrix:
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
         target:
           - aarch64-linux-android
           - arm-linux-gnueabihf
@@ -86,3 +91,4 @@ jobs:
 
       - name: Run smoke test
         run: bin/ci with_build_env make smoke_test target=${{ matrix.target }}
+        env: ${{ matrix.env }}

From 9a268aa905d6f01104feb241d9a79b0e39dd729e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:25:17 +0100
Subject: [PATCH 10/17] Add `env` to mingw

---
 .github/workflows/mingw-w64-steps.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.github/workflows/mingw-w64-steps.yml b/.github/workflows/mingw-w64-steps.yml
index f4740a9c425f..1e8b4586e36d 100644
--- a/.github/workflows/mingw-w64-steps.yml
+++ b/.github/workflows/mingw-w64-steps.yml
@@ -81,6 +81,14 @@ jobs:
 
   test-stdlib:
     runs-on: ${{ inputs.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
     steps:
       - name: Setup MSYS2
         id: msys2
@@ -109,6 +117,7 @@ jobs:
         run: |
           export CRYSTAL_SPEC_COMPILER_BIN="$(which crystal.exe)"
           make std_spec
+        env: ${{ matrix.env }}
 
   test-compiler:
     runs-on: ${{ inputs.runs-on }}

From 27acdbe0d89db03306fa08398ea1cf317c238f9e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 12:25:48 +0100
Subject: [PATCH 11/17] Add `env` to win

---
 .github/workflows/win.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.github/workflows/win.yml b/.github/workflows/win.yml
index 2d2f9a3bcc00..df20fc70bbf1 100644
--- a/.github/workflows/win.yml
+++ b/.github/workflows/win.yml
@@ -228,6 +228,15 @@ jobs:
   x86_64-windows-test:
     runs-on: windows-2025
     needs: [x86_64-windows-release]
+    strategy:
+      fail-fast: false
+      matrix:
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
+    env: ${{ matrix.env }}
     steps:
       - name: Disable CRLF line ending substitution
         run: |

From 41a0017381f625a7a0d476a432da8df11f128153 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 17:57:32 +0100
Subject: [PATCH 12/17] Move `env` to least precedence for automatic naming
 purposes

---
 .github/workflows/macos.yml |  2 +-
 .github/workflows/smoke.yml | 11 +++++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index f0f43f80e558..1bf0d2aa5256 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -17,12 +17,12 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     strategy:
       matrix:
+        runs-on: [macos-15-intel, macos-15]
         env: [
           {},
           {FLAGS: "-Duse_libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
-        runs-on: [macos-15-intel, macos-15]
       fail-fast: false
     steps:
       - name: Download Crystal source
diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index 364f23cfc618..2b75d9a3d2f4 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -57,18 +57,12 @@ env:
 
 jobs:
   smoke-test:
-    name: ${{ matrix.target }}
     runs-on: ubuntu-latest
 
     strategy:
       max-parallel: 2
       fail-fast: false
       matrix:
-        env: [
-          {},
-          {FLAGS: "-Duse_libevent"},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
         target:
           - aarch64-linux-android
           - arm-linux-gnueabihf
@@ -79,6 +73,11 @@ jobs:
           - x86_64-netbsd
           - x86_64-openbsd
           - x86_64-solaris
+        env: [
+          {},
+          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Dpreview_mt -Dexecution_context"},
+        ]
 
     steps:
       - name: Download Crystal source

From 4ec795bc75e30262e08c633a7482889d5c93681f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 5 Nov 2025 18:03:38 +0100
Subject: [PATCH 13/17] Drop extra job `x86_64-gnu-test-preview_mt`

---
 .github/workflows/linux.yml | 23 -----------------------
 1 file changed, 23 deletions(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index f3778a3e3e00..450a34a484b8 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -82,29 +82,6 @@ jobs:
         run: bin/ci build
         env: ${{ matrix.env }}
 
-  x86_64-gnu-test-preview_mt:
-    env:
-      ARCH: x86_64
-      ARCH_CMD: linux64
-    runs-on: ubuntu-latest
-    steps:
-      - name: Download Crystal source
-        uses: actions/checkout@v5
-        with:
-          persist-credentials: false
-
-      - name: Prepare System
-        run: bin/ci prepare_system
-
-      - name: Prepare Build
-        run: bin/ci prepare_build
-
-      - name: Make Crystal
-        run: bin/ci with_build_env 'make crystal'
-
-      - name: Test
-        run: bin/ci with_build_env 'CRYSTAL_WORKERS=4 make std_spec threads=1 FLAGS="-D preview_mt"'
-
   check_format:
     env:
       ARCH: x86_64

From 06eaef9ad91db27101ae2232f6f35db533c6e834 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Thu, 6 Nov 2025 12:30:51 +0100
Subject: [PATCH 14/17] Drop libevent from unsuppored platforms

---
 .github/workflows/mingw-w64-steps.yml | 1 -
 .github/workflows/smoke.yml           | 1 -
 .github/workflows/win.yml             | 1 -
 3 files changed, 3 deletions(-)

diff --git a/.github/workflows/mingw-w64-steps.yml b/.github/workflows/mingw-w64-steps.yml
index 1e8b4586e36d..c990a05e83be 100644
--- a/.github/workflows/mingw-w64-steps.yml
+++ b/.github/workflows/mingw-w64-steps.yml
@@ -86,7 +86,6 @@ jobs:
       matrix:
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
     steps:
diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index 2b75d9a3d2f4..9eeb7fe12e12 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -75,7 +75,6 @@ jobs:
           - x86_64-solaris
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
 
diff --git a/.github/workflows/win.yml b/.github/workflows/win.yml
index df20fc70bbf1..9babf3dade99 100644
--- a/.github/workflows/win.yml
+++ b/.github/workflows/win.yml
@@ -233,7 +233,6 @@ jobs:
       matrix:
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
     env: ${{ matrix.env }}

From 48c77859ad4e0a096e798e24c02831f905fc31f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Thu, 6 Nov 2025 12:31:09 +0100
Subject: [PATCH 15/17] Fix `-Devloop=libevent`

---
 .github/workflows/linux.yml | 4 ++--
 .github/workflows/macos.yml | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 450a34a484b8..dc52a606815b 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -27,7 +27,7 @@ jobs:
       matrix:
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Devloop=libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
         include:
@@ -63,7 +63,7 @@ jobs:
       matrix:
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Devloop=libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
     steps:
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 1bf0d2aa5256..888d1a0e0bee 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -20,7 +20,7 @@ jobs:
         runs-on: [macos-15-intel, macos-15]
         env: [
           {},
-          {FLAGS: "-Duse_libevent"},
+          {FLAGS: "-Devloop=libevent"},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
       fail-fast: false

From 0976ee959411c38a6af4613c3484ca36bb98ae7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Thu, 6 Nov 2025 12:31:33 +0100
Subject: [PATCH 16/17] Test freebsd with `evloop=libevent`

---
 .github/workflows/smoke.yml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index 9eeb7fe12e12..7cf7f5a27f2a 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -77,6 +77,10 @@ jobs:
           {},
           {FLAGS: "-Dpreview_mt -Dexecution_context"},
         ]
+        include:
+          - target: x86_64-freebsd
+            env:
+              FLAGS: "-Devloop=libevent"
 
     steps:
       - name: Download Crystal source

From f48b065185255582f670b05e992ef40d4382c5db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Thu, 6 Nov 2025 12:36:40 +0100
Subject: [PATCH 17/17] Format YAML

---
 .github/workflows/linux.yml           | 18 ++++++++----------
 .github/workflows/macos.yml           |  9 ++++-----
 .github/workflows/mingw-w64-steps.yml |  7 +++----
 .github/workflows/smoke.yml           |  7 +++----
 .github/workflows/win.yml             |  7 +++----
 5 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index dc52a606815b..2861a0a0ba20 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -25,11 +25,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        env: [
-          {},
-          {FLAGS: "-Devloop=libevent"},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Devloop=libevent"
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
         include:
           - env:
               CRYSTAL_BOOTSTRAP_VERSION: 1.0.0
@@ -61,11 +60,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        env: [
-          {},
-          {FLAGS: "-Devloop=libevent"},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Devloop=libevent"
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
     steps:
       - name: Download Crystal source
         uses: actions/checkout@v5
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 888d1a0e0bee..53660a2e43ef 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -18,11 +18,10 @@ jobs:
     strategy:
       matrix:
         runs-on: [macos-15-intel, macos-15]
-        env: [
-          {},
-          {FLAGS: "-Devloop=libevent"},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Devloop=libevent"
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
       fail-fast: false
     steps:
       - name: Download Crystal source
diff --git a/.github/workflows/mingw-w64-steps.yml b/.github/workflows/mingw-w64-steps.yml
index c990a05e83be..41595e197166 100644
--- a/.github/workflows/mingw-w64-steps.yml
+++ b/.github/workflows/mingw-w64-steps.yml
@@ -84,10 +84,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        env: [
-          {},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
     steps:
       - name: Setup MSYS2
         id: msys2
diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index 7cf7f5a27f2a..f3efa74d52db 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -73,10 +73,9 @@ jobs:
           - x86_64-netbsd
           - x86_64-openbsd
           - x86_64-solaris
-        env: [
-          {},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
         include:
           - target: x86_64-freebsd
             env:
diff --git a/.github/workflows/win.yml b/.github/workflows/win.yml
index 9babf3dade99..ba589236757b 100644
--- a/.github/workflows/win.yml
+++ b/.github/workflows/win.yml
@@ -231,10 +231,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        env: [
-          {},
-          {FLAGS: "-Dpreview_mt -Dexecution_context"},
-        ]
+        env:
+          - FLAGS: ""
+          - FLAGS: "-Dpreview_mt -Dexecution_context"
     env: ${{ matrix.env }}
     steps:
       - name: Disable CRLF line ending substitution