[pve-devel] [PATCH installer 2/3] auto: answer: deserialize empty domain name as `None`

[Christoph Heiss]

This handles the case where users set `global.fqdn.domain = ""`, which
would result incorrect parsing and finally resulting in the FQDN of the
target machine being set to `<productname>.example.invalid`.

Reported on the community forum [0].

[0] https://forum.proxmox.com/threads/auto-install-fetching-fqdn-through-dhcp-does-not-set-search-domain-correctly.168369/

Fixes: a37e044 ("fix #5811: auto: add option to retrieve FQDN from DHCP configuration")
Signed-off-by: Christoph Heiss <c.heiss at proxmox.com>
---
 proxmox-auto-installer/src/answer.rs          | 13 +++++++++++++
 proxmox-auto-installer/tests/parse-answer.rs  |  1 +
 ...n_from_dhcp_empty_dhcp_domain_setting.json | 19 +++++++++++++++++++
 ...n_from_dhcp_empty_dhcp_domain_setting.toml | 17 +++++++++++++++++
 4 files changed, 50 insertions(+)
 create mode 100644 proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.json
 create mode 100644 proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.toml

diff --git a/proxmox-auto-installer/src/answer.rs b/proxmox-auto-installer/src/answer.rs
index b461976..88f4c87 100644
--- a/proxmox-auto-installer/src/answer.rs
+++ b/proxmox-auto-installer/src/answer.rs
@@ -90,6 +90,7 @@ pub struct FqdnExtendedConfig {
     #[serde(default)]
     pub source: FqdnSourceMode,
     /// Domain to use if none is received via DHCP.
+    #[serde(default, deserialize_with = "deserialize_non_empty_string_maybe")]
     pub domain: Option<String>,
 }
 
@@ -444,3 +445,15 @@ pub enum KeyboardLayout {
 }
 
 serde_plain::derive_display_from_serialize!(KeyboardLayout);
+
+fn deserialize_non_empty_string_maybe<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let val: Option<String> = Deserialize::deserialize(deserializer)?;
+
+    match val {
+        Some(s) if !s.is_empty() => Ok(Some(s)),
+        _ => Ok(None),
+    }
+}
diff --git a/proxmox-auto-installer/tests/parse-answer.rs b/proxmox-auto-installer/tests/parse-answer.rs
index 88f30aa..a354f21 100644
--- a/proxmox-auto-installer/tests/parse-answer.rs
+++ b/proxmox-auto-installer/tests/parse-answer.rs
@@ -124,6 +124,7 @@ mod tests {
             disk_match_any,
             first_boot,
             fqdn_from_dhcp,
+            fqdn_from_dhcp_empty_dhcp_domain_setting,
             fqdn_from_dhcp_no_dhcp_domain_with_default_domain,
             full_fqdn_from_dhcp_with_default_domain,
             hashed_root_password,
diff --git a/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.json b/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.json
new file mode 100644
index 0000000..5ec6656
--- /dev/null
+++ b/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.json
@@ -0,0 +1,19 @@
+{
+  "autoreboot": 1,
+  "cidr": "192.168.1.114/24",
+  "country": "at",
+  "dns": "192.168.1.254",
+  "domain": "test.local",
+  "filesys": "ext4",
+  "gateway": "192.168.1.1",
+  "hdsize": 223.57088470458984,
+  "existing_storage_auto_rename": 1,
+  "hostname": "pveauto",
+  "keymap": "de",
+  "mailto": "mail at no.invalid",
+  "mngmt_nic": "eno1",
+  "root_password": { "plain": "12345678" },
+  "target_hd": "/dev/sda",
+  "timezone": "Europe/Vienna",
+  "first_boot": { "enabled": 0 }
+}
diff --git a/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.toml b/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.toml
new file mode 100644
index 0000000..a19e342
--- /dev/null
+++ b/proxmox-auto-installer/tests/resources/parse_answer/fqdn_from_dhcp_empty_dhcp_domain_setting.toml
@@ -0,0 +1,17 @@
+[global]
+keyboard = "de"
+country = "at"
+mailto = "mail at no.invalid"
+timezone = "Europe/Vienna"
+root-password = "12345678"
+
+[global.fqdn]
+source = "from-dhcp"
+domain = ""
+
+[network]
+source = "from-dhcp"
+
+[disk-setup]
+filesystem = "ext4"
+disk-list = ["sda"]
-- 
2.49.0