lib.rs

  1use proc_macro::TokenStream;
  2use quote::{format_ident, quote};
  3use std::mem;
  4use syn::{
  5    parse_macro_input, parse_quote, spanned::Spanned as _, AttributeArgs, FnArg, ItemFn, Lit, Meta,
  6    NestedMeta, Type,
  7};
  8
  9#[proc_macro_attribute]
 10pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
 11    let mut namespace = format_ident!("gpui");
 12
 13    let args = syn::parse_macro_input!(args as AttributeArgs);
 14    let mut max_retries = 0;
 15    let mut num_iterations = 1;
 16    let mut starting_seed = 0;
 17
 18    for arg in args {
 19        match arg {
 20            NestedMeta::Meta(Meta::Path(name))
 21                if name.get_ident().map_or(false, |n| n == "self") =>
 22            {
 23                namespace = format_ident!("crate");
 24            }
 25            NestedMeta::Meta(Meta::NameValue(meta)) => {
 26                let key_name = meta.path.get_ident().map(|i| i.to_string());
 27                let result = (|| {
 28                    match key_name.as_ref().map(String::as_str) {
 29                        Some("retries") => max_retries = parse_int(&meta.lit)?,
 30                        Some("iterations") => num_iterations = parse_int(&meta.lit)?,
 31                        Some("seed") => starting_seed = parse_int(&meta.lit)?,
 32                        _ => {
 33                            return Err(TokenStream::from(
 34                                syn::Error::new(meta.path.span(), "invalid argument")
 35                                    .into_compile_error(),
 36                            ))
 37                        }
 38                    }
 39                    Ok(())
 40                })();
 41
 42                if let Err(tokens) = result {
 43                    return tokens;
 44                }
 45            }
 46            other => {
 47                return TokenStream::from(
 48                    syn::Error::new_spanned(other, "invalid argument").into_compile_error(),
 49                )
 50            }
 51        }
 52    }
 53
 54    let mut inner_fn = parse_macro_input!(function as ItemFn);
 55    if max_retries > 0 && num_iterations > 1 {
 56        return TokenStream::from(
 57            syn::Error::new_spanned(inner_fn, "retries and randomized iterations can't be mixed")
 58                .into_compile_error(),
 59        );
 60    }
 61    let inner_fn_attributes = mem::take(&mut inner_fn.attrs);
 62    let inner_fn_name = format_ident!("_{}", inner_fn.sig.ident);
 63    let outer_fn_name = mem::replace(&mut inner_fn.sig.ident, inner_fn_name.clone());
 64
 65    let mut outer_fn: ItemFn = if inner_fn.sig.asyncness.is_some() {
 66        // Pass to the test function the number of app contexts that it needs,
 67        // based on its parameter list.
 68        let mut inner_fn_args = proc_macro2::TokenStream::new();
 69        for (ix, arg) in inner_fn.sig.inputs.iter().enumerate() {
 70            if let FnArg::Typed(arg) = arg {
 71                if let Type::Path(ty) = &*arg.ty {
 72                    let last_segment = ty.path.segments.last();
 73                    match last_segment.map(|s| s.ident.to_string()).as_deref() {
 74                        Some("TestAppContext") => {
 75                            let first_entity_id = ix * 100_000;
 76                            inner_fn_args.extend(quote!(#namespace::TestAppContext::new(
 77                                foreground_platform.clone(),
 78                                platform.clone(),
 79                                foreground.clone(),
 80                                background.clone(),
 81                                font_cache.clone(),
 82                                #first_entity_id),
 83                            ));
 84                        }
 85                        Some("StdRng") => {
 86                            inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed)));
 87                        }
 88                        _ => {
 89                            return TokenStream::from(
 90                                syn::Error::new_spanned(arg, "invalid argument")
 91                                    .into_compile_error(),
 92                            )
 93                        }
 94                    }
 95                } else {
 96                    return TokenStream::from(
 97                        syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
 98                    );
 99                }
100            } else {
101                return TokenStream::from(
102                    syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
103                );
104            }
105        }
106
107        parse_quote! {
108            #[test]
109            fn #outer_fn_name() {
110                #inner_fn
111
112                let is_randomized = #num_iterations > 1;
113                let mut num_iterations = #num_iterations as u64;
114                let mut starting_seed = #starting_seed as u64;
115                if is_randomized {
116                    if let Ok(value) = std::env::var("SEED") {
117                        starting_seed = value.parse().expect("invalid SEED variable");
118                    }
119                    if let Ok(value) = std::env::var("ITERATIONS") {
120                        num_iterations = value.parse().expect("invalid ITERATIONS variable");
121                    }
122                }
123
124                let mut atomic_seed = std::sync::atomic::AtomicU64::new(starting_seed as u64);
125                let mut retries = 0;
126
127                loop {
128                    let result = std::panic::catch_unwind(|| {
129                        let foreground_platform = std::rc::Rc::new(#namespace::platform::test::foreground_platform());
130                        let platform = std::sync::Arc::new(#namespace::platform::test::platform());
131                        let font_system = #namespace::Platform::fonts(platform.as_ref());
132                        let font_cache = std::sync::Arc::new(#namespace::FontCache::new(font_system));
133
134                        loop {
135                            let seed = atomic_seed.load(std::sync::atomic::Ordering::SeqCst);
136                            if seed >= starting_seed + num_iterations {
137                                break;
138                            }
139
140                            if is_randomized {
141                                dbg!(seed);
142                            }
143
144                            let (foreground, background) = #namespace::executor::deterministic(seed);
145                            foreground.run(#inner_fn_name(#inner_fn_args));
146                            atomic_seed.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
147                        }
148                    });
149
150                    match result {
151                        Ok(result) => {
152                            break;
153                        }
154                        Err(error) => {
155                            if retries < #max_retries {
156                                retries += 1;
157                                println!("retrying: attempt {}", retries);
158                            } else {
159                                if is_randomized {
160                                    eprintln!("failing seed: {}", atomic_seed.load(std::sync::atomic::Ordering::SeqCst));
161                                }
162                                std::panic::resume_unwind(error);
163                            }
164                        }
165                    }
166                }
167            }
168        }
169    } else {
170        let mut inner_fn_args = proc_macro2::TokenStream::new();
171        for arg in inner_fn.sig.inputs.iter() {
172            if let FnArg::Typed(arg) = arg {
173                if let Type::Path(ty) = &*arg.ty {
174                    let last_segment = ty.path.segments.last();
175                    if let Some("StdRng") = last_segment.map(|s| s.ident.to_string()).as_deref() {
176                        inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed),));
177                    }
178                } else {
179                    inner_fn_args.extend(quote!(cx,));
180                }
181            } else {
182                return TokenStream::from(
183                    syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
184                );
185            }
186        }
187
188        parse_quote! {
189            #[test]
190            fn #outer_fn_name() {
191                #inner_fn
192
193                let is_randomized = #num_iterations > 1;
194                let mut num_iterations = #num_iterations as u64;
195                let mut starting_seed = #starting_seed as u64;
196                if is_randomized {
197                    if let Ok(value) = std::env::var("SEED") {
198                        starting_seed = value.parse().expect("invalid SEED variable");
199                    }
200                    if let Ok(value) = std::env::var("ITERATIONS") {
201                        num_iterations = value.parse().expect("invalid ITERATIONS variable");
202                    }
203                }
204
205                let mut atomic_seed = std::sync::atomic::AtomicU64::new(starting_seed as u64);
206                let mut retries = 0;
207
208                loop {
209                    let result = std::panic::catch_unwind(|| {
210                        let foreground_platform = std::rc::Rc::new(#namespace::platform::test::foreground_platform());
211                        let platform = std::sync::Arc::new(#namespace::platform::test::platform());
212                        let font_system = #namespace::Platform::fonts(platform.as_ref());
213                        let font_cache = std::sync::Arc::new(#namespace::FontCache::new(font_system));
214
215                        loop {
216                            let seed = atomic_seed.load(std::sync::atomic::Ordering::SeqCst);
217                            if seed >= starting_seed + num_iterations {
218                                break;
219                            }
220
221                            if is_randomized {
222                                dbg!(seed);
223                            }
224
225                            #namespace::App::test(foreground_platform.clone(), platform.clone(), font_cache.clone(), |cx| {
226                                #inner_fn_name(#inner_fn_args);
227                            });
228                            atomic_seed.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
229                        }
230                    });
231
232                    match result {
233                        Ok(_) => {
234                            break;
235                        }
236                        Err(error) => {
237                            if retries < #max_retries {
238                                retries += 1;
239                                println!("retrying: attempt {}", retries);
240                            } else {
241                                if is_randomized {
242                                    eprintln!("failing seed: {}", atomic_seed.load(std::sync::atomic::Ordering::SeqCst));
243                                }
244                                std::panic::resume_unwind(error);
245                            }
246                        }
247                    }
248                }
249            }
250        }
251    };
252    outer_fn.attrs.extend(inner_fn_attributes);
253
254    TokenStream::from(quote!(#outer_fn))
255}
256
257fn parse_int(literal: &Lit) -> Result<usize, TokenStream> {
258    let result = if let Lit::Int(int) = &literal {
259        int.base10_parse()
260    } else {
261        Err(syn::Error::new(literal.span(), "must be an integer"))
262    };
263
264    result.map_err(|err| TokenStream::from(err.into_compile_error()))
265}