Provide intention to fill struct members

[mkaput]

Implement the following intention in CairoLS:

[the-first-elder]

Hi @mkaput can you provide a link to this on the codebase

[mkaput]

Hey! Here's the starting point:

cairo/crates/cairo-lang-language-server/src/ide/code_actions/mod.rs

Lines 34 to 78 in cdaceb9

	/// Generate code actions for a given diagnostic.
	///
	/// # Arguments
	///
	/// * `db` - A reference to the Salsa database.
	/// * `node` - The syntax node where the diagnostic is located.
	/// * `diagnostic` - The diagnostic for which to generate code actions.
	/// * `params` - The parameters for the code action request.
	///
	/// # Returns
	///
	/// A vector of [`CodeAction`] objects that can be applied to resolve the diagnostic.
	fn get_code_actions_for_diagnostic(
	db: &AnalysisDatabase,
	node: &SyntaxNode,
	diagnostic: &Diagnostic,
	params: &CodeActionParams,
	) -> Vec<CodeAction> {
	let code = match &diagnostic.code {
	Some(NumberOrString::String(code)) => code,
	Some(NumberOrString::Number(code)) => {
	debug!("diagnostic code is not a string: `{code}`");
	return vec![];
	}
	None => {
	debug!("diagnostic code is missing");
	return vec![];
	}
	};
	match code.as_str() {
	"E0001" => {
	vec![rename_unused_variable::rename_unused_variable(
	db,
	node,
	diagnostic.clone(),
	params.text_document.uri.clone(),
	)]
	}
	code => {
	debug!("no code actions for diagnostic code: {code}");
	vec![]
	}
	}
	}

You can follow the implementation of unused variable intention as the hooking point. First, you need to assign an error code to this particular diagnostic; you can grep for it by error message.

You will need to get information about struct members. This is provided in the SemanticGroup (this trait-Salsa group is implemented by AnalysisDatabase) by this query:

cairo/crates/cairo-lang-semantic/src/db.rs

Lines 233 to 238 in 50d465c

	/// Returns the members of a struct.
	#[salsa::invoke(items::structure::struct_members)]
	fn struct_members(
	&self,
	struct_id: StructId,
	) -> Maybe<OrderedHashMap<SmolStr, semantic::Member>>;

[the-first-elder]

Hi @mkaput I'm having issues getting the struct_Id, also there is no fix struct field error, i created an error code for missing members

[piotmag769]

@the-first-elder

there is no fix struct field error, i created an error code for missing members

That's good, that's what was supposed to be done!

I'm having issues getting the struct_Id

You need to get the StructId from the SyntaxNode when you already recognised that the MissingMember diagnostic was returned for the node. Since you can deduct (from the diagnostic) that the SyntaxNode contains struct expression, you need to find an expr node of appropriate kind (probably SyntaxKind::ExprStructCtorCal, but not sure about that). Checking the code from dot_completions may be helpful. Then when you get the type, do this:

cairo/crates/cairo-lang-language-server/src/ide/completion/completions.rs

Lines 241 to 244 in cdaceb9

	let (_, long_ty) = peel_snapshots(db, ty);
	if let TypeLongId::Concrete(ConcreteTypeId::Struct(concrete_struct_id)) = long_ty {
	db.concrete_struct_members(concrete_struct_id).ok()?.into_iter().for_each(
	|(name, member)| {

and you have the member names 🙂

You can check this PR, maybe it will help you with implementation

[mkaput]

@the-first-elder any progress? how can we help?

[the-first-elder]

This is what i have currently done, I do need some guidance in getting it right.

pub fn fill_struct_fields(
    db: &AnalysisDatabase,
    node: &SyntaxNode,
    diagnostic: Diagnostic,
    uri: Url,
) -> CodeAction {
    // Resolve the StructId from the SyntaxNode
    let struct_id = resolve_struct_id(db, node).expect("Failed to resolve StructId");

    let members = get_struct_members(db.upcast(), struct_id)
    .expect("Failed to extract struct members");


    // Create the text edit
    let text_edit = TextEdit {
        range: diagnostic.range,
        new_text: format!("{{ {} }}", generate_default_values(&members)),
    };

    CodeAction {
        title: "Fill missing struct fields".to_string(),
        edit: Some(WorkspaceEdit {
            changes: Some(HashMap::from([(uri, vec![text_edit])])),
            document_changes: None,
            change_annotations: None,
        }),
        diagnostics: Some(vec![diagnostic]),
        ..Default::default()
    }
}

fn resolve_struct_id(db: &AnalysisDatabase, node: &SyntaxNode) -> Option<StructId> {
    let syntax_db = db.upcast();

    if node.kind(syntax_db) == SyntaxKind::ExprStructCtorCall {

        let lookup_item_id = db.find_lookup_item(&node)?;
        let function_id = lookup_item_id.function_with_body()?;
        let expr_id = db.lookup_expr_by_ptr(function_id, node.stable_ptr()).ok()?;
        let semantic_expr = db.expr_semantic(function_id, expr_id);

        let ty = semantic_expr.ty();
        if ty.is_missing(db) {
            return None;
        }

        let (_, long_ty) = peel_snapshots(db, ty);
        if let TypeLongId::Concrete(ConcreteTypeId::Struct(concrete_struct_id)) = long_ty {
            return Some(concrete_struct_id.struct_id(db));
        }
    }

    None
}

fn get_struct_members(db: &dyn SemanticGroup, struct_id: StructId) -> Maybe<OrderedHashMap<SmolStr, Member>> {
    db.struct_members(struct_id)
}


fn generate_default_values(members: &OrderedHashMap<SmolStr, Member>) -> String {
    members.iter().map(|(name, _)| format!("{}: default_value", name)).collect::<Vec<_>>().join(", ")
}

[piotmag769]

@the-first-elder looks like a solid work! Have you tried if it works? You can do it via building the LS from source and setting

{    
    "cairo1.languageServerPath": "/Users/piotrmagiera/SWM/Dev/cairo/target/release/cairo-language-server",
    "cairo1.preferScarbLanguageServer": false,
 }

in .vscode/settings.json You can also access the file via command/crtl + shift + P + > ... open user settings (JSON) shortcut.

Regarding the implementation I am worried that checking if the syntax node is of kind ExprStructCtorCall directly may not work, it will be probably one of the parents of the node.

Regarding the default_value that you want to fill the struct members with I think it would be reasonable to check if the type has Default implementation: if so, we can just drop Default::default() there. Not sure what we should do if there is no Default implemented for the member, any idea @mkaput?

[mkaput]

Regarding the default_value that you want to fill the struct members with I think it would be reasonable to check if the type has Default implementation: if so, we can just drop Default::default() there. Not sure what we should do if there is no Default implemented for the member, any idea @mkaput?

Just put () (unit value/empty tuple) in such case and expect people to fix compilation errors.

[the-first-elder]

i get this when i try to hover Request textDocument/hover failed.

[piotmag769]

Does it happen on your branch? Or the main one?

[the-first-elder]

mine but same on main as well

[piotmag769]

Could you provide reproduction for that in another issue?

[mkaput]

Unassigning due to lack of activity.

[poolcleaner6]

It might be helpful to outline the main areas where incremental updates could have the biggest impact, especially if the goal is to improve responsiveness with large files. Is there any specific guidance on this?

[mkaput]

@poolcleaner6 I'm responding on CairoLS Telegram channel, that's a more proper place for this topic than this issue :)