fix autofmt: don't panic when writing blocks out without a srcfile (#2854)

* fix: don't panic when writing blocks out
* also fix serialization for hotreload
* fix windows line endings

packages/autofmt/src/lib.rs

@@ -93,7 +93,7 @@ pub fn try_fmt_file(
         writer.out.indent_level = writer
             .out
             .indent
-            .count_indents(writer.src[rsx_start.line - 1]);
+            .count_indents(writer.src.get(rsx_start.line - 1).unwrap_or(&""));
 
         // TESTME
         // Writing *should* not fail but it's possible that it does

packages/autofmt/src/writer.rs

@@ -607,7 +607,11 @@ impl<'a> Writer<'a> {
 
         let mut comments = VecDeque::new();
 
-        for (id, line) in self.src[..line_start].iter().enumerate().rev() {
+        let Some(lines) = self.src.get(..line_start) else {
+            return comments;
+        };
+
+        for (id, line) in lines.iter().enumerate().rev() {
             if line.trim().starts_with("//") || line.is_empty() && id != 0 {
                 if id != 0 {
                     comments.push_front(id);
@@ -621,7 +625,11 @@ impl<'a> Writer<'a> {
     }
     fn apply_comments(&mut self, mut comments: VecDeque<usize>) -> Result {
         while let Some(comment_line) = comments.pop_front() {
-            let line = &self.src[comment_line].trim();
+            let Some(line) = self.src.get(comment_line) else {
+                continue;
+            };
+
+            let line = &line.trim();
 
             if line.is_empty() {
                 self.out.new_line()?;
@@ -690,13 +698,15 @@ impl<'a> Writer<'a> {
 
         for attr in attributes {
             if self.current_span_is_primary(attr.span().start()) {
-                'line: for line in self.src[..attr.span().start().line - 1].iter().rev() {
-                    match (line.trim().starts_with("//"), line.is_empty()) {
-                        (true, _) => return 100000,
-                        (_, true) => continue 'line,
-                        _ => break 'line,
+                if let Some(lines) = self.src.get(..attr.span().start().line - 1) {
+                    'line: for line in lines.iter().rev() {
+                        match (line.trim().starts_with("//"), line.is_empty()) {
+                            (true, _) => return 100000,
+                            (_, true) => continue 'line,
+                            _ => break 'line,
+                        }
                     }
-                }
+                };
             }
 
             let name_len = match &attr.name {
@@ -738,7 +748,9 @@ impl<'a> Writer<'a> {
         writeln!(self.out)?;
 
         for idx in start.line..end.line {
-            let line = &self.src[idx];
+            let Some(line) = self.src.get(idx) else {
+                continue;
+            };
             if line.trim().starts_with("//") {
                 for _ in 0..self.out.indent_level + 1 {
                     write!(self.out, "    ")?

packages/autofmt/tests/srcless.rs

@@ -0,0 +1,21 @@
+use dioxus_rsx::CallBody;
+use proc_macro2::TokenStream as TokenStream2;
+
+/// Ensure we can write RSX blocks without a source file
+///
+/// Useful in code generation use cases where we still want formatted code.
+#[test]
+fn write_block_out() {
+    let src = include_str!("./srcless/basic_expr.rsx");
+
+    let tokens: TokenStream2 = syn::parse_str(src).unwrap();
+    let parsed: CallBody = syn::parse2(tokens).unwrap();
+
+    let block = dioxus_autofmt::write_block_out(&parsed).unwrap();
+
+    // normalize line endings for windows tests to pass
+    pretty_assertions::assert_eq!(
+        block.trim().lines().collect::<Vec<_>>().join("\n"),
+        src.trim().lines().collect::<Vec<_>>().join("\n")
+    );
+}

packages/autofmt/tests/srcless/basic_expr.rsx

@@ -0,0 +1,42 @@
+    div {
+        "hi"
+        {children}
+    }
+    Fragment {
+        Fragment {
+            Fragment {
+                Fragment {
+                    Fragment {
+                        div { "Finally have a real node!" }
+                    }
+                }
+            }
+        }
+    }
+    div { class, "hello world" }
+    h1 { class, "hello world" }
+    h1 { class, {children} }
+    h1 { class, id, {children} }
+    h1 { class,
+        "hello world"
+        {children}
+    }
+    h1 { id,
+        "hello world"
+        {children}
+    }
+    Other { class, children }
+    Other { class,
+        "hello world"
+        {children}
+    }
+    div {
+        class: "asdasd",
+        onclick: move |_| {
+            let a = 10;
+            let b = 40;
+            let c = 50;
+        },
+        "hi"
+    }
+    div { class: "asd", "Jon" }