From 65baf3fcd3e9ee1c6b55b620fb09cb0b1a621bb5 Mon Sep 17 00:00:00 2001
From: TheAwiteb <awiteb@hotmail.com>
Date: Thu, 2 Mar 2023 15:07:03 +0300
Subject: [PATCH] Replace `#[doc = ".."]` with `#[command(description =
 "...")]`

---
 crates/teloxide-macros/src/command_attr.rs | 36 ++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/crates/teloxide-macros/src/command_attr.rs b/crates/teloxide-macros/src/command_attr.rs
index 1e01aed1..dcc9f148 100644
--- a/crates/teloxide-macros/src/command_attr.rs
+++ b/crates/teloxide-macros/src/command_attr.rs
@@ -7,7 +7,8 @@ use crate::{
 };
 
 use proc_macro2::Span;
-use syn::Attribute;
+use quote::quote_spanned;
+use syn::{parse::Parser, spanned::Spanned, Attribute};
 
 /// All attributes that can be used for `derive(BotCommands)`
 pub(crate) struct CommandAttrs {
@@ -48,9 +49,40 @@ enum CommandAttrKind {
 impl CommandAttrs {
     pub fn from_attributes(attributes: &[Attribute]) -> Result<Self> {
         use CommandAttrKind::*;
+        // Convert the `doc` attribute into `command(description = "...")`
+        let attributes = attributes
+            .iter()
+            .map(|attr| {
+                if attr.path.is_ident("doc") {
+                    // Extract the token literal from the doc attribute.
+                    let description = attr
+                        .tokens
+                        .clone()
+                        .into_iter()
+                        .nth(1)
+                        .map(|t| {
+                            // remove first and last quotes only, is expected to be a string literal
+                            let mut s = t.to_string();
+                            s.remove(0);
+                            s.pop();
+                            s.trim().replace(r"\\n", "\n")
+                        })
+                        .unwrap_or_default();
+                    // Convert the doc attribute into a command description attribute.
+                    let sp = attr.span();
+                    let attr = Attribute::parse_outer
+                        .parse2(quote_spanned!(sp => #[command(description = #description)]))
+                        .unwrap();
+                    // SAFETY: `parse_outer` always returns a single attribute.
+                    attr.into_iter().next().unwrap()
+                } else {
+                    attr.clone()
+                }
+            })
+            .collect::<Vec<_>>();
 
         fold_attrs(
-            attributes,
+            attributes.iter(),
             is_command_attribute,
             CommandAttr::parse,
             Self {