]>
Commit | Line | Data |
---|---|---|
8faf50e0 | 1 | use internals::ast::{Container, Data, Field, Style}; |
f9f354fc | 2 | use internals::attr::{Identifier, TagType}; |
8faf50e0 XL |
3 | use internals::{Ctxt, Derive}; |
4 | use syn::{Member, Type}; | |
3b2f2976 XL |
5 | |
6 | /// Cross-cutting checks that require looking at more than a single attrs | |
7 | /// object. Simpler checks should happen when parsing and building the attrs. | |
8faf50e0 | 8 | pub fn check(cx: &Ctxt, cont: &mut Container, derive: Derive) { |
3b2f2976 | 9 | check_getter(cx, cont); |
0531ce1d | 10 | check_flatten(cx, cont); |
3b2f2976 | 11 | check_identifier(cx, cont); |
ea8adc8c | 12 | check_variant_skip_attrs(cx, cont); |
0531ce1d XL |
13 | check_internal_tag_field_name_conflict(cx, cont); |
14 | check_adjacent_tag_conflict(cx, cont); | |
8faf50e0 | 15 | check_transparent(cx, cont, derive); |
f9f354fc | 16 | check_from_and_try_from(cx, cont); |
3b2f2976 XL |
17 | } |
18 | ||
19 | /// Getters are only allowed inside structs (not enums) with the `remote` | |
20 | /// attribute. | |
21 | fn check_getter(cx: &Ctxt, cont: &Container) { | |
0531ce1d XL |
22 | match cont.data { |
23 | Data::Enum(_) => { | |
24 | if cont.data.has_getter() { | |
0731742a XL |
25 | cx.error_spanned_by( |
26 | cont.original, | |
27 | "#[serde(getter = \"...\")] is not allowed in an enum", | |
28 | ); | |
3b2f2976 XL |
29 | } |
30 | } | |
0531ce1d XL |
31 | Data::Struct(_, _) => { |
32 | if cont.data.has_getter() && cont.attrs.remote().is_none() { | |
0731742a XL |
33 | cx.error_spanned_by( |
34 | cont.original, | |
f9f354fc | 35 | "#[serde(getter = \"...\")] can only be used in structs that have #[serde(remote = \"...\")]", |
3b2f2976 XL |
36 | ); |
37 | } | |
38 | } | |
39 | } | |
40 | } | |
41 | ||
0531ce1d XL |
42 | /// Flattening has some restrictions we can test. |
43 | fn check_flatten(cx: &Ctxt, cont: &Container) { | |
f9f354fc XL |
44 | match &cont.data { |
45 | Data::Enum(variants) => { | |
8faf50e0 XL |
46 | for variant in variants { |
47 | for field in &variant.fields { | |
48 | check_flatten_field(cx, variant.style, field); | |
49 | } | |
83c7162d | 50 | } |
0531ce1d | 51 | } |
f9f354fc | 52 | Data::Struct(style, fields) => { |
8faf50e0 | 53 | for field in fields { |
f9f354fc | 54 | check_flatten_field(cx, *style, field); |
0531ce1d XL |
55 | } |
56 | } | |
57 | } | |
58 | } | |
59 | ||
8faf50e0 XL |
60 | fn check_flatten_field(cx: &Ctxt, style: Style, field: &Field) { |
61 | if !field.attrs.flatten() { | |
62 | return; | |
63 | } | |
64 | match style { | |
65 | Style::Tuple => { | |
0731742a XL |
66 | cx.error_spanned_by( |
67 | field.original, | |
68 | "#[serde(flatten)] cannot be used on tuple structs", | |
69 | ); | |
8faf50e0 XL |
70 | } |
71 | Style::Newtype => { | |
0731742a XL |
72 | cx.error_spanned_by( |
73 | field.original, | |
74 | "#[serde(flatten)] cannot be used on newtype structs", | |
75 | ); | |
8faf50e0 XL |
76 | } |
77 | _ => {} | |
78 | } | |
8faf50e0 XL |
79 | } |
80 | ||
3b2f2976 | 81 | /// The `other` attribute must be used at most once and it must be the last |
0731742a | 82 | /// variant of an enum. |
3b2f2976 XL |
83 | /// |
84 | /// Inside a `variant_identifier` all variants must be unit variants. Inside a | |
85 | /// `field_identifier` all but possibly one variant must be unit variants. The | |
86 | /// last variant may be a newtype variant which is an implicit "other" case. | |
87 | fn check_identifier(cx: &Ctxt, cont: &Container) { | |
f9f354fc XL |
88 | let variants = match &cont.data { |
89 | Data::Enum(variants) => variants, | |
0531ce1d | 90 | Data::Struct(_, _) => { |
3b2f2976 XL |
91 | return; |
92 | } | |
93 | }; | |
94 | ||
95 | for (i, variant) in variants.iter().enumerate() { | |
ff7c6d11 XL |
96 | match ( |
97 | variant.style, | |
98 | cont.attrs.identifier(), | |
99 | variant.attrs.other(), | |
0731742a | 100 | cont.attrs.tag(), |
ff7c6d11 | 101 | ) { |
0731742a XL |
102 | // The `other` attribute may not be used in a variant_identifier. |
103 | (_, Identifier::Variant, true, _) => { | |
104 | cx.error_spanned_by( | |
105 | variant.original, | |
106 | "#[serde(other)] may not be used on a variant identifier", | |
107 | ); | |
108 | } | |
109 | ||
110 | // Variant with `other` attribute cannot appear in untagged enum | |
f9f354fc | 111 | (_, Identifier::No, true, &TagType::None) => { |
0731742a XL |
112 | cx.error_spanned_by( |
113 | variant.original, | |
114 | "#[serde(other)] cannot appear on untagged enum", | |
115 | ); | |
3b2f2976 XL |
116 | } |
117 | ||
118 | // Variant with `other` attribute must be the last one. | |
0731742a | 119 | (Style::Unit, Identifier::Field, true, _) | (Style::Unit, Identifier::No, true, _) => { |
3b2f2976 | 120 | if i < variants.len() - 1 { |
0731742a XL |
121 | cx.error_spanned_by( |
122 | variant.original, | |
123 | "#[serde(other)] must be on the last variant", | |
124 | ); | |
3b2f2976 XL |
125 | } |
126 | } | |
127 | ||
128 | // Variant with `other` attribute must be a unit variant. | |
0731742a XL |
129 | (_, Identifier::Field, true, _) | (_, Identifier::No, true, _) => { |
130 | cx.error_spanned_by( | |
131 | variant.original, | |
132 | "#[serde(other)] must be on a unit variant", | |
133 | ); | |
3b2f2976 XL |
134 | } |
135 | ||
136 | // Any sort of variant is allowed if this is not an identifier. | |
0731742a | 137 | (_, Identifier::No, false, _) => {} |
3b2f2976 XL |
138 | |
139 | // Unit variant without `other` attribute is always fine. | |
0731742a | 140 | (Style::Unit, _, false, _) => {} |
3b2f2976 XL |
141 | |
142 | // The last field is allowed to be a newtype catch-all. | |
0731742a | 143 | (Style::Newtype, Identifier::Field, false, _) => { |
3b2f2976 | 144 | if i < variants.len() - 1 { |
0731742a XL |
145 | cx.error_spanned_by( |
146 | variant.original, | |
147 | format!("`{}` must be the last variant", variant.ident), | |
148 | ); | |
3b2f2976 XL |
149 | } |
150 | } | |
151 | ||
0731742a XL |
152 | (_, Identifier::Field, false, _) => { |
153 | cx.error_spanned_by( | |
154 | variant.original, | |
155 | "#[serde(field_identifier)] may only contain unit variants", | |
156 | ); | |
3b2f2976 XL |
157 | } |
158 | ||
0731742a XL |
159 | (_, Identifier::Variant, false, _) => { |
160 | cx.error_spanned_by( | |
161 | variant.original, | |
162 | "#[serde(variant_identifier)] may only contain unit variants", | |
163 | ); | |
3b2f2976 XL |
164 | } |
165 | } | |
166 | } | |
167 | } | |
ea8adc8c XL |
168 | |
169 | /// Skip-(de)serializing attributes are not allowed on variants marked | |
170 | /// (de)serialize_with. | |
171 | fn check_variant_skip_attrs(cx: &Ctxt, cont: &Container) { | |
f9f354fc XL |
172 | let variants = match &cont.data { |
173 | Data::Enum(variants) => variants, | |
0531ce1d | 174 | Data::Struct(_, _) => { |
ea8adc8c XL |
175 | return; |
176 | } | |
177 | }; | |
178 | ||
179 | for variant in variants.iter() { | |
180 | if variant.attrs.serialize_with().is_some() { | |
181 | if variant.attrs.skip_serializing() { | |
f9f354fc XL |
182 | cx.error_spanned_by( |
183 | variant.original, | |
184 | format!( | |
185 | "variant `{}` cannot have both #[serde(serialize_with)] and #[serde(skip_serializing)]", | |
186 | variant.ident | |
187 | ), | |
188 | ); | |
ea8adc8c XL |
189 | } |
190 | ||
8faf50e0 XL |
191 | for field in &variant.fields { |
192 | let member = member_message(&field.member); | |
ea8adc8c XL |
193 | |
194 | if field.attrs.skip_serializing() { | |
f9f354fc XL |
195 | cx.error_spanned_by( |
196 | variant.original, | |
197 | format!( | |
198 | "variant `{}` cannot have both #[serde(serialize_with)] and a field {} marked with #[serde(skip_serializing)]", | |
199 | variant.ident, member | |
200 | ), | |
201 | ); | |
ea8adc8c XL |
202 | } |
203 | ||
204 | if field.attrs.skip_serializing_if().is_some() { | |
f9f354fc XL |
205 | cx.error_spanned_by( |
206 | variant.original, | |
207 | format!( | |
208 | "variant `{}` cannot have both #[serde(serialize_with)] and a field {} marked with #[serde(skip_serializing_if)]", | |
209 | variant.ident, member | |
210 | ), | |
211 | ); | |
ea8adc8c XL |
212 | } |
213 | } | |
214 | } | |
215 | ||
216 | if variant.attrs.deserialize_with().is_some() { | |
217 | if variant.attrs.skip_deserializing() { | |
f9f354fc XL |
218 | cx.error_spanned_by( |
219 | variant.original, | |
220 | format!( | |
221 | "variant `{}` cannot have both #[serde(deserialize_with)] and #[serde(skip_deserializing)]", | |
222 | variant.ident | |
223 | ), | |
224 | ); | |
ea8adc8c XL |
225 | } |
226 | ||
8faf50e0 | 227 | for field in &variant.fields { |
ea8adc8c | 228 | if field.attrs.skip_deserializing() { |
8faf50e0 | 229 | let member = member_message(&field.member); |
ff7c6d11 | 230 | |
f9f354fc XL |
231 | cx.error_spanned_by( |
232 | variant.original, | |
233 | format!( | |
234 | "variant `{}` cannot have both #[serde(deserialize_with)] and a field {} marked with #[serde(skip_deserializing)]", | |
235 | variant.ident, member | |
236 | ), | |
237 | ); | |
ea8adc8c XL |
238 | } |
239 | } | |
240 | } | |
241 | } | |
242 | } | |
0531ce1d XL |
243 | |
244 | /// The tag of an internally-tagged struct variant must not be | |
245 | /// the same as either one of its fields, as this would result in | |
246 | /// duplicate keys in the serialized output and/or ambiguity in | |
247 | /// the to-be-deserialized input. | |
83c7162d | 248 | fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) { |
f9f354fc XL |
249 | let variants = match &cont.data { |
250 | Data::Enum(variants) => variants, | |
0531ce1d XL |
251 | Data::Struct(_, _) => return, |
252 | }; | |
253 | ||
f9f354fc XL |
254 | let tag = match cont.attrs.tag() { |
255 | TagType::Internal { tag } => tag.as_str(), | |
256 | TagType::External | TagType::Adjacent { .. } | TagType::None => return, | |
0531ce1d XL |
257 | }; |
258 | ||
f9f354fc XL |
259 | let diagnose_conflict = || { |
260 | cx.error_spanned_by( | |
261 | cont.original, | |
262 | format!("variant field name `{}` conflicts with internal tag", tag), | |
263 | ) | |
264 | }; | |
0531ce1d XL |
265 | |
266 | for variant in variants { | |
267 | match variant.style { | |
268 | Style::Struct => { | |
269 | for field in &variant.fields { | |
270 | let check_ser = !field.attrs.skip_serializing(); | |
271 | let check_de = !field.attrs.skip_deserializing(); | |
272 | let name = field.attrs.name(); | |
273 | let ser_name = name.serialize_name(); | |
0531ce1d | 274 | |
f9f354fc | 275 | if check_ser && ser_name == tag { |
0531ce1d XL |
276 | diagnose_conflict(); |
277 | return; | |
278 | } | |
f9f354fc XL |
279 | |
280 | for de_name in field.attrs.aliases() { | |
281 | if check_de && de_name == tag { | |
282 | diagnose_conflict(); | |
283 | return; | |
284 | } | |
285 | } | |
0531ce1d | 286 | } |
83c7162d XL |
287 | } |
288 | Style::Unit | Style::Newtype | Style::Tuple => {} | |
0531ce1d XL |
289 | } |
290 | } | |
291 | } | |
292 | ||
293 | /// In the case of adjacently-tagged enums, the type and the | |
294 | /// contents tag must differ, for the same reason. | |
295 | fn check_adjacent_tag_conflict(cx: &Ctxt, cont: &Container) { | |
f9f354fc XL |
296 | let (type_tag, content_tag) = match cont.attrs.tag() { |
297 | TagType::Adjacent { tag, content } => (tag, content), | |
298 | TagType::Internal { .. } | TagType::External | TagType::None => return, | |
0531ce1d XL |
299 | }; |
300 | ||
301 | if type_tag == content_tag { | |
f9f354fc XL |
302 | cx.error_spanned_by( |
303 | cont.original, | |
304 | format!( | |
305 | "enum tags `{}` for type and content conflict with each other", | |
306 | type_tag | |
307 | ), | |
308 | ); | |
0531ce1d XL |
309 | } |
310 | } | |
8faf50e0 XL |
311 | |
312 | /// Enums and unit structs cannot be transparent. | |
313 | fn check_transparent(cx: &Ctxt, cont: &mut Container, derive: Derive) { | |
314 | if !cont.attrs.transparent() { | |
315 | return; | |
316 | } | |
317 | ||
318 | if cont.attrs.type_from().is_some() { | |
0731742a XL |
319 | cx.error_spanned_by( |
320 | cont.original, | |
321 | "#[serde(transparent)] is not allowed with #[serde(from = \"...\")]", | |
322 | ); | |
8faf50e0 XL |
323 | } |
324 | ||
f9f354fc XL |
325 | if cont.attrs.type_try_from().is_some() { |
326 | cx.error_spanned_by( | |
327 | cont.original, | |
328 | "#[serde(transparent)] is not allowed with #[serde(try_from = \"...\")]", | |
329 | ); | |
330 | } | |
331 | ||
8faf50e0 | 332 | if cont.attrs.type_into().is_some() { |
0731742a XL |
333 | cx.error_spanned_by( |
334 | cont.original, | |
335 | "#[serde(transparent)] is not allowed with #[serde(into = \"...\")]", | |
336 | ); | |
8faf50e0 XL |
337 | } |
338 | ||
f9f354fc | 339 | let fields = match &mut cont.data { |
8faf50e0 | 340 | Data::Enum(_) => { |
0731742a XL |
341 | cx.error_spanned_by( |
342 | cont.original, | |
343 | "#[serde(transparent)] is not allowed on an enum", | |
344 | ); | |
8faf50e0 XL |
345 | return; |
346 | } | |
347 | Data::Struct(Style::Unit, _) => { | |
0731742a XL |
348 | cx.error_spanned_by( |
349 | cont.original, | |
350 | "#[serde(transparent)] is not allowed on a unit struct", | |
351 | ); | |
8faf50e0 XL |
352 | return; |
353 | } | |
f9f354fc | 354 | Data::Struct(_, fields) => fields, |
8faf50e0 XL |
355 | }; |
356 | ||
357 | let mut transparent_field = None; | |
358 | ||
359 | for field in fields { | |
360 | if allow_transparent(field, derive) { | |
361 | if transparent_field.is_some() { | |
0731742a XL |
362 | cx.error_spanned_by( |
363 | cont.original, | |
8faf50e0 XL |
364 | "#[serde(transparent)] requires struct to have at most one transparent field", |
365 | ); | |
366 | return; | |
367 | } | |
368 | transparent_field = Some(field); | |
369 | } | |
370 | } | |
371 | ||
372 | match transparent_field { | |
373 | Some(transparent_field) => transparent_field.attrs.mark_transparent(), | |
374 | None => match derive { | |
375 | Derive::Serialize => { | |
0731742a XL |
376 | cx.error_spanned_by( |
377 | cont.original, | |
378 | "#[serde(transparent)] requires at least one field that is not skipped", | |
379 | ); | |
8faf50e0 XL |
380 | } |
381 | Derive::Deserialize => { | |
0731742a XL |
382 | cx.error_spanned_by( |
383 | cont.original, | |
384 | "#[serde(transparent)] requires at least one field that is neither skipped nor has a default", | |
385 | ); | |
8faf50e0 XL |
386 | } |
387 | }, | |
388 | } | |
389 | } | |
390 | ||
391 | fn member_message(member: &Member) -> String { | |
f9f354fc XL |
392 | match member { |
393 | Member::Named(ident) => format!("`{}`", ident), | |
394 | Member::Unnamed(i) => format!("#{}", i.index), | |
8faf50e0 XL |
395 | } |
396 | } | |
397 | ||
398 | fn allow_transparent(field: &Field, derive: Derive) -> bool { | |
f9f354fc | 399 | if let Type::Path(ty) = field.ty { |
8faf50e0 | 400 | if let Some(seg) = ty.path.segments.last() { |
f9f354fc | 401 | if seg.ident == "PhantomData" { |
8faf50e0 XL |
402 | return false; |
403 | } | |
404 | } | |
405 | } | |
406 | ||
407 | match derive { | |
408 | Derive::Serialize => !field.attrs.skip_serializing(), | |
409 | Derive::Deserialize => !field.attrs.skip_deserializing() && field.attrs.default().is_none(), | |
410 | } | |
411 | } | |
f9f354fc XL |
412 | |
413 | fn check_from_and_try_from(cx: &Ctxt, cont: &mut Container) { | |
414 | if cont.attrs.type_from().is_some() && cont.attrs.type_try_from().is_some() { | |
415 | cx.error_spanned_by( | |
416 | cont.original, | |
417 | "#[serde(from = \"...\")] and #[serde(try_from = \"...\")] conflict with each other", | |
418 | ); | |
419 | } | |
420 | } |