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Auto merge of #53893 - petrochenkov:cfgexpr, r=pnkfelix
Validate syntax of `cfg` attributes Fixes #53298
2 parents 5a3292f + a6adeae commit 24ef47b

13 files changed

+180
-54
lines changed

‎src/librustc/session/config.rs

+25-14
Original file line numberDiff line numberDiff line change
@@ -21,7 +21,7 @@ use rustc_target::spec::{Target, TargetTriple};
2121
use lint;
2222
use middle::cstore;
2323

24-
use syntax::ast::{self, IntTy, UintTy};
24+
use syntax::ast::{self, IntTy, UintTy, MetaItemKind};
2525
use syntax::source_map::{FileName, FilePathMapping};
2626
use syntax::edition::{Edition, EDITION_NAME_LIST, DEFAULT_EDITION};
2727
use syntax::parse::token;
@@ -1735,22 +1735,33 @@ pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> ast::CrateConfig {
17351735
let mut parser =
17361736
parse::new_parser_from_source_str(&sess, FileName::CfgSpec, s.to_string());
17371737

1738-
let meta_item = panictry!(parser.parse_meta_item());
1738+
macro_rules! error {($reason: expr) => {
1739+
early_error(ErrorOutputType::default(),
1740+
&format!(concat!("invalid `--cfg` argument: `{}` (", $reason, ")"), s));
1741+
}}
17391742

1740-
if parser.token != token::Eof {
1741-
early_error(
1742-
ErrorOutputType::default(),
1743-
&format!("invalid --cfg argument: {}", s),
1744-
)
1745-
} else if meta_item.is_meta_item_list() {
1746-
let msg = format!(
1747-
"invalid predicate in --cfg command line argument: `{}`",
1748-
meta_item.ident
1749-
);
1750-
early_error(ErrorOutputType::default(), &msg)
1743+
match &mut parser.parse_meta_item() {
1744+
Ok(meta_item) if parser.token == token::Eof => {
1745+
if meta_item.ident.segments.len() != 1 {
1746+
error!("argument key must be an identifier");
1747+
}
1748+
match &meta_item.node {
1749+
MetaItemKind::List(..) => {
1750+
error!(r#"expected `key` or `key="value"`"#);
1751+
}
1752+
MetaItemKind::NameValue(lit) if !lit.node.is_str() => {
1753+
error!("argument value must be a string");
1754+
}
1755+
MetaItemKind::NameValue(..) | MetaItemKind::Word => {
1756+
return (meta_item.name(), meta_item.value_str());
1757+
}
1758+
}
1759+
}
1760+
Ok(..) => {}
1761+
Err(err) => err.cancel(),
17511762
}
17521763

1753-
(meta_item.name(), meta_item.value_str())
1764+
error!(r#"expected `key` or `key="value"`"#);
17541765
})
17551766
.collect::<ast::CrateConfig>()
17561767
}

‎src/libsyntax/attr/builtin.rs

+15-1
Original file line numberDiff line numberDiff line change
@@ -433,7 +433,21 @@ pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Feat
433433
if let (Some(feats), Some(gated_cfg)) = (features, GatedCfg::gate(cfg)) {
434434
gated_cfg.check_and_emit(sess, feats);
435435
}
436-
sess.config.contains(&(cfg.name(), cfg.value_str()))
436+
let error = |span, msg| { sess.span_diagnostic.span_err(span, msg); true };
437+
if cfg.ident.segments.len() != 1 {
438+
return error(cfg.ident.span, "`cfg` predicate key must be an identifier");
439+
}
440+
match &cfg.node {
441+
MetaItemKind::List(..) => {
442+
error(cfg.span, "unexpected parentheses after `cfg` predicate key")
443+
}
444+
MetaItemKind::NameValue(lit) if !lit.node.is_str() => {
445+
error(lit.span, "literal in `cfg` predicate value must be a string")
446+
}
447+
MetaItemKind::NameValue(..) | MetaItemKind::Word => {
448+
sess.config.contains(&(cfg.name(), cfg.value_str()))
449+
}
450+
}
437451
})
438452
}
439453

‎src/libsyntax/config.rs

+32-12
Original file line numberDiff line numberDiff line change
@@ -116,25 +116,45 @@ impl<'a> StripUnconfigured<'a> {
116116
// Determine if a node with the given attributes should be included in this configuration.
117117
pub fn in_cfg(&mut self, attrs: &[ast::Attribute]) -> bool {
118118
attrs.iter().all(|attr| {
119-
let mis = if !is_cfg(attr) {
119+
if !is_cfg(attr) {
120120
return true;
121-
} else if let Some(mis) = attr.meta_item_list() {
122-
mis
121+
}
122+
123+
let error = |span, msg, suggestion: &str| {
124+
let mut err = self.sess.span_diagnostic.struct_span_err(span, msg);
125+
if !suggestion.is_empty() {
126+
err.span_suggestion(span, "expected syntax is", suggestion.into());
127+
}
128+
err.emit();
129+
true
130+
};
131+
132+
let meta_item = if let Some(meta_item) = attr.meta() {
133+
meta_item
123134
} else {
124-
return true;
135+
// Not a well-formed meta-item. Why? We don't know.
136+
return error(attr.span, "`cfg` is not a well-formed meta-item",
137+
"#[cfg(/* predicate */)]");
138+
};
139+
let nested_meta_items = if let Some(nested_meta_items) = meta_item.meta_item_list() {
140+
nested_meta_items
141+
} else {
142+
return error(meta_item.span, "`cfg` is not followed by parentheses",
143+
"cfg(/* predicate */)");
125144
};
126145

127-
if mis.len() != 1 {
128-
self.sess.span_diagnostic.span_err(attr.span, "expected 1 cfg-pattern");
129-
return true;
146+
if nested_meta_items.is_empty() {
147+
return error(meta_item.span, "`cfg` predicate is not specified", "");
148+
} else if nested_meta_items.len() > 1 {
149+
return error(nested_meta_items.last().unwrap().span,
150+
"multiple `cfg` predicates are specified", "");
130151
}
131152

132-
if !mis[0].is_meta_item() {
133-
self.sess.span_diagnostic.span_err(mis[0].span, "unexpected literal");
134-
return true;
153+
match nested_meta_items[0].meta_item() {
154+
Some(meta_item) => attr::cfg_matches(meta_item, self.sess, self.features),
155+
None => error(nested_meta_items[0].span,
156+
"`cfg` predicate key cannot be a literal", ""),
135157
}
136-
137-
attr::cfg_matches(mis[0].meta_item().unwrap(), self.sess, self.features)
138158
})
139159
}
140160

‎src/test/ui/cfg-arg-invalid-1.rs

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
// compile-flags: --cfg a(b=c)
2+
// error-pattern: invalid `--cfg` argument: `a(b=c)` (expected `key` or `key="value"`)
3+
fn main() {}

‎src/test/ui/cfg-arg-invalid-2.rs

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
// compile-flags: --cfg a{b}
2+
// error-pattern: invalid `--cfg` argument: `a{b}` (expected `key` or `key="value"`)
3+
fn main() {}

‎src/test/ui/cfg-arg-invalid-3.rs

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
// compile-flags: --cfg a::b
2+
// error-pattern: invalid `--cfg` argument: `a::b` (argument key must be an identifier)
3+
fn main() {}

‎src/test/ui/cfg-arg-invalid-4.rs

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
// compile-flags: --cfg a(b)
2+
// error-pattern: invalid `--cfg` argument: `a(b)` (expected `key` or `key="value"`)
3+
fn main() {}

‎src/test/ui/cfg-arg-invalid-5.rs

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
// compile-flags: --cfg a=10
2+
// error-pattern: invalid `--cfg` argument: `a=10` (argument value must be a string)
3+
fn main() {}

‎src/test/ui/cfg-arg-invalid.rs

-13
This file was deleted.

‎src/test/ui/cfg-attr-syntax-validation.rs

+32
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
1+
#[cfg] //~ ERROR `cfg` is not followed by parentheses
2+
struct S1;
3+
4+
#[cfg = 10] //~ ERROR `cfg` is not followed by parentheses
5+
struct S2;
6+
7+
#[cfg()] //~ ERROR `cfg` predicate is not specified
8+
struct S3;
9+
10+
#[cfg(a, b)] //~ ERROR multiple `cfg` predicates are specified
11+
struct S4;
12+
13+
#[cfg("str")] //~ ERROR `cfg` predicate key cannot be a literal
14+
struct S5;
15+
16+
#[cfg(a::b)] //~ ERROR `cfg` predicate key must be an identifier
17+
struct S6;
18+
19+
#[cfg(a())] //~ ERROR invalid predicate `a`
20+
struct S7;
21+
22+
#[cfg(a = 10)] //~ ERROR literal in `cfg` predicate value must be a string
23+
struct S8;
24+
25+
macro_rules! generate_s9 {
26+
($expr: expr) => {
27+
#[cfg(feature = $expr)] //~ ERROR `cfg` is not a well-formed meta-item
28+
struct S9;
29+
}
30+
}
31+
32+
generate_s9!(concat!("nonexistent"));

‎src/test/ui/cfg-attr-syntax-validation.stderr

+60
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,60 @@
1+
error: `cfg` is not followed by parentheses
2+
--> $DIR/cfg-attr-syntax-validation.rs:1:1
3+
|
4+
LL | #[cfg] //~ ERROR `cfg` is not followed by parentheses
5+
| ^^^^^^ help: expected syntax is: `cfg(/* predicate */)`
6+
7+
error: `cfg` is not followed by parentheses
8+
--> $DIR/cfg-attr-syntax-validation.rs:4:1
9+
|
10+
LL | #[cfg = 10] //~ ERROR `cfg` is not followed by parentheses
11+
| ^^^^^^^^^^^ help: expected syntax is: `cfg(/* predicate */)`
12+
13+
error: `cfg` predicate is not specified
14+
--> $DIR/cfg-attr-syntax-validation.rs:7:1
15+
|
16+
LL | #[cfg()] //~ ERROR `cfg` predicate is not specified
17+
| ^^^^^^^^
18+
19+
error: multiple `cfg` predicates are specified
20+
--> $DIR/cfg-attr-syntax-validation.rs:10:10
21+
|
22+
LL | #[cfg(a, b)] //~ ERROR multiple `cfg` predicates are specified
23+
| ^
24+
25+
error: `cfg` predicate key cannot be a literal
26+
--> $DIR/cfg-attr-syntax-validation.rs:13:7
27+
|
28+
LL | #[cfg("str")] //~ ERROR `cfg` predicate key cannot be a literal
29+
| ^^^^^
30+
31+
error: `cfg` predicate key must be an identifier
32+
--> $DIR/cfg-attr-syntax-validation.rs:16:7
33+
|
34+
LL | #[cfg(a::b)] //~ ERROR `cfg` predicate key must be an identifier
35+
| ^^^^
36+
37+
error[E0537]: invalid predicate `a`
38+
--> $DIR/cfg-attr-syntax-validation.rs:19:7
39+
|
40+
LL | #[cfg(a())] //~ ERROR invalid predicate `a`
41+
| ^^^
42+
43+
error: literal in `cfg` predicate value must be a string
44+
--> $DIR/cfg-attr-syntax-validation.rs:22:11
45+
|
46+
LL | #[cfg(a = 10)] //~ ERROR literal in `cfg` predicate value must be a string
47+
| ^^
48+
49+
error: `cfg` is not a well-formed meta-item
50+
--> $DIR/cfg-attr-syntax-validation.rs:27:9
51+
|
52+
LL | #[cfg(feature = $expr)] //~ ERROR `cfg` is not a well-formed meta-item
53+
| ^^^^^^^^^^^^^^^^^^^^^^^ help: expected syntax is: `#[cfg(/* predicate */)]`
54+
...
55+
LL | generate_s9!(concat!("nonexistent"));
56+
| ------------------------------------- in this macro invocation
57+
58+
error: aborting due to 9 previous errors
59+
60+
For more information about this error, try `rustc --explain E0537`.

‎src/test/ui/cfg-empty-codemap.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@
1212

1313
// compile-flags: --cfg ""
1414

15-
// error-pattern: expected identifier, found
15+
// error-pattern: invalid `--cfg` argument: `""` (expected `key` or `key="value"`)
1616

1717
pub fn main() {
1818
}

‎src/test/ui/issues/issue-31495.rs

-13
This file was deleted.

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