install: support configuring sysroot.bls-append-except-default

Add a new [install.ostree] configuration section to allow setting the
ostree sysroot.bls-append-except-default option during installation.

Closes: https://github.com/bootc-dev/bootc/issues/1710

Signed-off-by: Joel Capitao <jcapitao@redhat.com>
Co-authored-by: Jean-Baptiste Trystram <jbtrystram@redhat.com>
Assisted-by: Claude (Sonnet 4)

crates/lib/src/install.rs

@@ -795,7 +795,21 @@ async fn initialize_ostree_root(state: &State, root_setup: &RootSetup) -> Result
         crate::lsm::ensure_dir_labeled(rootfs_dir, "boot", None, 0o755.into(), sepolicy)?;
     }
 
-    for (k, v) in DEFAULT_REPO_CONFIG.iter() {
+    // Build the list of ostree repo config options: defaults + install config
+    let ostree_opts = state
+        .install_config
+        .as_ref()
+        .and_then(|c| c.ostree.as_ref())
+        .into_iter()
+        .flat_map(|o| o.to_config_tuples());
+
+    let repo_config: Vec<_> = DEFAULT_REPO_CONFIG
+        .iter()
+        .copied()
+        .chain(ostree_opts)
+        .collect();
+
+    for (k, v) in repo_config.iter() {
         Command::new("ostree")
             .args(["config", "--repo", "ostree/repo", "set", k, v])
             .cwd_dir(rootfs_dir.try_clone()?)

crates/lib/src/install/config.rs

@@ -58,6 +58,9 @@ pub(crate) struct BasicFilesystems {
     // pub(crate) esp: Option<FilesystemCustomization>,
 }
 
+/// Configuration for ostree repository
+pub(crate) type OstreeRepoOpts = ostree_ext::repo_options::RepoOptions;
+
 /// The serialized [install] section
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
 #[serde(rename = "install", rename_all = "kebab-case", deny_unknown_fields)]
@@ -73,6 +76,8 @@ pub(crate) struct InstallConfiguration {
     pub(crate) kargs: Option<Vec<String>>,
     /// Supported architectures for this configuration
     pub(crate) match_architectures: Option<Vec<String>>,
+    /// Ostree repository configuration
+    pub(crate) ostree: Option<OstreeRepoOpts>,
 }
 
 fn merge_basic<T>(s: &mut Option<T>, o: Option<T>, _env: &EnvProperties) {
@@ -119,6 +124,17 @@ impl Mergeable for BasicFilesystems {
     }
 }
 
+impl Mergeable for OstreeRepoOpts {
+    /// Apply any values in other, overriding any existing values in `self`.
+    fn merge(&mut self, other: Self, env: &EnvProperties) {
+        merge_basic(
+            &mut self.bls_append_except_default,
+            other.bls_append_except_default,
+            env,
+        )
+    }
+}
+
 impl Mergeable for InstallConfiguration {
     /// Apply any values in other, overriding any existing values in `self`.
     fn merge(&mut self, other: Self, env: &EnvProperties) {
@@ -133,6 +149,7 @@ impl Mergeable for InstallConfiguration {
             #[cfg(feature = "install-to-disk")]
             merge_basic(&mut self.block, other.block, env);
             self.filesystem.merge(other.filesystem, env);
+            self.ostree.merge(other.ostree, env);
             if let Some(other_kargs) = other.kargs {
                 self.kargs
                     .get_or_insert_with(Default::default)
@@ -572,4 +589,54 @@ root-fs-type = "xfs"
             )
         );
     }
+
+    #[test]
+    fn test_parse_ostree() {
+        let env = EnvProperties {
+            sys_arch: "x86_64".to_string(),
+        };
+
+        // Table-driven test cases for parsing bls-append-except-default
+        let parse_cases = [
+            ("console=ttyS0", "console=ttyS0"),
+            ("console=ttyS0,115200n8", "console=ttyS0,115200n8"),
+            ("rd.lvm.lv=vg/root", "rd.lvm.lv=vg/root"),
+        ];
+        for (input, expected) in parse_cases {
+            let toml_str = format!(
+                r#"[install.ostree]
+bls-append-except-default = "{input}"
+"#
+            );
+            let c: InstallConfigurationToplevel = toml::from_str(&toml_str).unwrap();
+            assert_eq!(
+                c.install
+                    .unwrap()
+                    .ostree
+                    .unwrap()
+                    .bls_append_except_default
+                    .unwrap(),
+                expected
+            );
+        }
+
+        // Test merging: other config should override original
+        let mut install: InstallConfiguration = toml::from_str(
+            r#"[ostree]
+bls-append-except-default = "console=ttyS0"
+"#,
+        )
+        .unwrap();
+        let other = InstallConfiguration {
+            ostree: Some(OstreeRepoOpts {
+                bls_append_except_default: Some("console=tty0".to_string()),
+            }),
+            ..Default::default()
+        };
+        install.merge(other, &env);
+        assert_eq!(
+            install.ostree.unwrap().bls_append_except_default.unwrap(),
+            "console=tty0"
+        );
+    }
 }

crates/ostree-ext/src/lib.rs

@@ -47,6 +47,7 @@ pub mod ostree_prepareroot;
 pub mod refescape;
 #[doc(hidden)]
 pub mod repair;
+pub mod repo_options;
 pub mod sysroot;
 pub mod tar;
 pub mod tokio_util;

crates/ostree-ext/src/repo_options.rs

@@ -0,0 +1,30 @@
+//! Configuration options for an ostree repository
+
+use serde::{Deserialize, Serialize};
+
+/// Configuration options for an ostree repository.
+///
+/// This struct represents configurable options for an ostree repository
+/// that can be set via the `ostree config set` command.
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case", default)]
+pub struct RepoOptions {
+    /// Boot Loader Spec entries that should append arguments only for non-default entries.
+    ///
+    /// Corresponds to the `sysroot.bls-append-except-default` ostree config key.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub bls_append_except_default: Option<String>,
+}
+
+impl RepoOptions {
+    /// Returns an iterator of (key, value) tuples for ostree repo configuration.
+    ///
+    /// Each tuple represents an ostree config key and its value, suitable for
+    /// passing to `ostree config set`.
+    pub fn to_config_tuples(&self) -> impl Iterator<Item = (&'static str, &str)> {
+        self.bls_append_except_default
+            .as_ref()
+            .map(|v| ("sysroot.bls-append-except-default", v.as_str()))
+            .into_iter()
+    }
+}

crates/tests-integration/src/container.rs

@@ -102,9 +102,16 @@ pub(crate) fn test_bootc_install_config() -> Result<()> {
 }
 
 pub(crate) fn test_bootc_install_config_all() -> Result<()> {
+    #[derive(Deserialize)]
+    #[serde(rename_all = "kebab-case")]
+    struct TestOstreeConfig {
+        bls_append_except_default: Option<String>,
+    }
+
     #[derive(Deserialize)]
     struct TestInstallConfig {
         kargs: Vec<String>,
+        ostree: Option<TestOstreeConfig>,
     }
 
     let config_d = std::path::Path::new("/run/bootc/install/");
@@ -113,6 +120,8 @@ pub(crate) fn test_bootc_install_config_all() -> Result<()> {
     let content = indoc! {r#"
         [install]
         kargs = ["karg1=1", "karg2=2"]
+        [install.ostree]
+        bls-append-except-default = "grub_users=\"\""
     "#};
     std::fs::write(&test_toml_path, content)?;
     defer! {
@@ -124,6 +133,13 @@ pub(crate) fn test_bootc_install_config_all() -> Result<()> {
     let config: TestInstallConfig =
         serde_json::from_str(&config).context("Parsing install config")?;
     assert_eq! {config.kargs, vec!["karg1=1".to_string(), "karg2=2".to_string(), "localtestkarg=somevalue".to_string(), "otherlocalkarg=42".to_string()]};
+    assert_eq!(
+        config
+            .ostree
+            .as_ref()
+            .and_then(|o| o.bls_append_except_default.as_deref()),
+        Some("grub_users=\"\"")
+    );
     Ok(())
 }