From f934195c9631be9c9da3d11b2f23d042dc342b7c Mon Sep 17 00:00:00 2001
From: Max Roeleveld <m.g.roeleveld@rug.nl>
Date: Mon, 10 Jun 2024 14:38:28 +0200
Subject: [PATCH 1/2] Use a slightly uglier but more reliable way of
 determining GRUB_CMDLINE_LINUX_DEFAULT.

---
 roles/grubcmdline/tasks/main.yml | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/roles/grubcmdline/tasks/main.yml b/roles/grubcmdline/tasks/main.yml
index e191d83..a9171b6 100644
--- a/roles/grubcmdline/tasks/main.yml
+++ b/roles/grubcmdline/tasks/main.yml
@@ -15,16 +15,19 @@
   changed_when: old_cmdline != kernel_cmdline | select() | sort | list
   notify: "{{ kernel_restart_handler }}"
 
-- name: Slurp /etc/default/grub
-  ansible.builtin.slurp:
-    path: /etc/default/grub
-  register: grub_result
-  become: true
-
-- name: Set fact containing GRUB_CMDLINE_LINUX_DEFAULT
+- name: Look for the last occurance of GRUB_CMDLINE_LINUX_DEFAULT in grub config
+  # In some environments, the grub config contained multiple lines defining this
+  # value; the last one would "win", but the change in this play would be based
+  # on the first one that was found, with interesting consequences. Hence this
+  # slightly less pure but more reliable way of fetching that line.
+  ansible.builtin.shell:
+    cmd: >-
+      grep -E '^GRUB_CMDLINE_LINUX_DEFAULT' /etc/default/grub | tail -1
+  register: grub_cmdline_linux_default
+- name: Set fact containing the contents of GRUB_CMDLINE_LINUX_DEFAULT
   ansible.builtin.set_fact:
     grub_cmdline_linux_default: >-
-      {{ grub_result.content | b64decode | regex_search('^GRUB_CMDLINE_LINUX_DEFAULT.*$', multiline=True) | regex_replace('^GRUB_CMDLINE_LINUX_DEFAULT="(.*)"$', '\1') }}
+      {{ grub_cmdline_linux_default.stdout | regex_search('^GRUB_CMDLINE_LINUX_DEFAULT.*$', multiline=True) | regex_replace('^GRUB_CMDLINE_LINUX_DEFAULT="(.*)"$', '\1') }}
 - name: Display GRUB_CMDLINE_DEFAULT
   ansible.builtin.debug:
     var: grub_cmdline_linux_default

From fbb1be4d19c782b2e69ddbd9f277a22b77c4b7bf Mon Sep 17 00:00:00 2001
From: Max Roeleveld <m.g.roeleveld@rug.nl>
Date: Mon, 10 Jun 2024 15:16:38 +0200
Subject: [PATCH 2/2] Appease the linter gods and make the shell command more
 reliable.

---
 roles/grubcmdline/tasks/main.yml | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/roles/grubcmdline/tasks/main.yml b/roles/grubcmdline/tasks/main.yml
index a9171b6..c42d2f1 100644
--- a/roles/grubcmdline/tasks/main.yml
+++ b/roles/grubcmdline/tasks/main.yml
@@ -22,8 +22,13 @@
   # slightly less pure but more reliable way of fetching that line.
   ansible.builtin.shell:
     cmd: >-
-      grep -E '^GRUB_CMDLINE_LINUX_DEFAULT' /etc/default/grub | tail -1
+      set -o pipefail
+      && grep -E '^GRUB_CMDLINE_LINUX_DEFAULT' /etc/default/grub | tail -1
+    args:
+      executable: /usr/bin/bash
   register: grub_cmdline_linux_default
+  changed_when: grub_cmdline_linux_default.rc != 0
+
 - name: Set fact containing the contents of GRUB_CMDLINE_LINUX_DEFAULT
   ansible.builtin.set_fact:
     grub_cmdline_linux_default: >-
@@ -36,7 +41,7 @@
   # We use a regex here so you can remove parameters regardless of their value, e.g to remove iommu=on you
   # could use the regex: ^iommu=
   ansible.builtin.set_fact:
-    grub_cmdline_linux_remove: "{{ grub_cmdline_linux_default.split() | select('search', kernel_cmdline_remove_regex) | list }}"
+    wrub_cmdline_linux_remove: "{{ grub_cmdline_linux_default.split() | select('search', kernel_cmdline_remove_regex) | list }}"
 
 - name: Display parameters to be removed
   ansible.builtin.debug: