Improve error messages by showing more context

[fingolfin]

E.g. when failing to modify a file, include the path to the file.

Resolves #1430.

Co-authored-by: Codex codex@openai.com

[fingolfin]

Tests pass. I manually went over the PR to verify the AI did not produce arbitrary garbage, it all seems sensible. Though of course I can not guarantee it is all perfect (I couldn't if I had written it myself either...). Though if this causes regressions, I offer to take care of them (in the worst case by reverting select messages to their prior state).

I also verified that it improves the error message in cases I care about. So I hope this can be merged?

[fingolfin]

(In other words: would be great if someone could approve this, then I can merge it... ;-) )

[IanButterworth]

Looks good to me, but Claude found further fixes and a correction to lump into this

diff --git a/src/command_override.rs b/src/command_override.rs
index e150c09..02c76c5 100644
--- a/src/command_override.rs
+++ b/src/command_override.rs
@@ -160,7 +160,7 @@ pub fn run_command_override_unset(
 
     save_config_db(&mut config_file).with_context(|| {
         format!(
-            "Failed to save configuration file from `override add` command at `{}`.",
+            "Failed to save configuration file from `override unset` command at `{}`.",
             paths.juliaupconfig.display()
         )
     })?;
diff --git a/src/operations.rs b/src/operations.rs
index 9c8a7b5..3191cb6 100644
--- a/src/operations.rs
+++ b/src/operations.rs
@@ -1237,9 +1237,13 @@ pub fn garbage_collect_versions(
 }
 
 fn _remove_symlink(symlink_path: &Path) -> Result<Option<PathBuf>> {
-    std::fs::create_dir_all(symlink_path.parent().unwrap()).with_context(|| {
+    let parent = symlink_path
+        .parent()
+        .ok_or_else(|| anyhow!("Symlink path `{}` has no parent directory.", symlink_path.display()))?;
+    std::fs::create_dir_all(parent).with_context(|| {
         format!(
-            "Failed to create parent directory for symlink `{}`.",
+            "Failed to create parent directory `{}` for symlink `{}`.",
+            parent.display(),
             symlink_path.display()
         )
     })?;

[fingolfin]

I've asked Codex to look for similar issues, and it found a few more, all addressed now, I hope. Let's see if your AI likes what my AI did ;-)

[IanButterworth]

Just needs conflicts resolved

[IanButterworth]

Messed up merge?

[fingolfin]

I let the AI do the merge. It messed up badly. I've now redone it manually