refactor: disable julia startup file for julia package update (#983)

* refactor(julia): disable julia startup file for julia package update

* feat(julia): add configuration option for julia startup file

* fix: deny unknown fields on JuliaConfig deserialisation

Co-authored-by: SteveLauC <stevelauc@outlook.com>

* doc(julia): clarify startup_file option purpose

---------

Co-authored-by: SteveLauC <stevelauc@outlook.com>

config.example.toml

@@ -270,3 +270,11 @@
 # and the update will be installed system-wide, i.e., available to all users.
 # (default: false)
 # use_sudo = false
+
+[julia]
+# If disabled, Topgrade invokes julia with the --startup-file=no CLI option.
+#
+# This may be desirable to avoid loading outdated packages with "using" directives
+# in the startup file, which might cause the update run to fail.
+# (default: true)
+# startup_file = true

src/config.rs

@@ -452,6 +452,12 @@ pub struct Lensfun {
     use_sudo: Option<bool>,
 }
 
+#[derive(Deserialize, Default, Debug, Merge)]
+#[serde(deny_unknown_fields)]
+pub struct JuliaConfig {
+    startup_file: Option<bool>,
+}
+
 #[derive(Deserialize, Default, Debug, Merge)]
 #[serde(deny_unknown_fields)]
 /// Configuration file
@@ -518,6 +524,9 @@ pub struct ConfigFile {
 
     #[merge(strategy = crate::utils::merge_strategies::inner_merge_opt)]
     lensfun: Option<Lensfun>,
+
+    #[merge(strategy = crate::utils::merge_strategies::inner_merge_opt)]
+    julia: Option<JuliaConfig>,
 }
 
 fn config_directory() -> PathBuf {
@@ -1632,6 +1641,14 @@ impl Config {
             .and_then(|lensfun| lensfun.use_sudo)
             .unwrap_or(false)
     }
+
+    pub fn julia_use_startup_file(&self) -> bool {
+        self.config_file
+            .julia
+            .as_ref()
+            .and_then(|julia| julia.startup_file)
+            .unwrap_or(true)
+    }
 }
 
 #[cfg(test)]

src/steps/generic.rs

@@ -908,10 +908,15 @@ pub fn update_julia_packages(ctx: &ExecutionContext) -> Result<()> {
 
     print_separator(t!("Julia Packages"));
 
-    ctx.run_type()
+    let mut executor = ctx.run_type().execute(julia);
-        .execute(julia)
+
-        .args(["-e", "using Pkg; Pkg.update()"])
+    executor.arg(if ctx.config().julia_use_startup_file() {
-        .status_checked()
+        "--startup-file=yes"
+    } else {
+        "--startup-file=no"
+    });
+
+    executor.args(["-e", "using Pkg; Pkg.update()"]).status_checked()
 }
 
 pub fn run_helm_repo_update(ctx: &ExecutionContext) -> Result<()> {