Include input in error message when `...not_matches...` assertions fail.
Recently, I've often found myself wondering what the exact input was that
contained the unexpected pattern, so this seems useful.
PiperOrigin-RevId: 420999635
diff --git a/rs_bindings_from_cc/token_stream_matchers.rs b/rs_bindings_from_cc/token_stream_matchers.rs
index b9a8def..beb6e45 100644
--- a/rs_bindings_from_cc/token_stream_matchers.rs
+++ b/rs_bindings_from_cc/token_stream_matchers.rs
@@ -40,7 +40,7 @@
#[macro_export]
macro_rules! assert_cc_matches {
($input:expr, $pattern:expr $(,)*) => {
- $crate::internal::match_tokens(&$input, &$pattern, $crate::internal::tokens_to_string)
+ $crate::internal::match_tokens(&$input, &$pattern, &$crate::internal::tokens_to_string)
.expect("input unexpectedly didn't match the pattern");
};
}
@@ -53,7 +53,7 @@
$crate::internal::match_tokens(
&$input,
&$pattern,
- $crate::internal::rs_tokens_to_formatted_string,
+ &$crate::internal::rs_tokens_to_formatted_string,
)
.expect("input unexpectedly didn't match the pattern");
};
@@ -65,8 +65,8 @@
#[macro_export]
macro_rules! assert_cc_not_matches {
($input:expr, $pattern:expr $(,)*) => {
- $crate::internal::match_tokens(&$input, &$pattern, $crate::internal::tokens_to_string)
- .expect_err("input unexpectedly matched the pattern");
+ $crate::internal::mismatch_tokens(&$input, &$pattern, &$crate::internal::tokens_to_string)
+ .unwrap();
};
}
@@ -75,12 +75,12 @@
#[macro_export]
macro_rules! assert_rs_not_matches {
($input:expr, $pattern:expr $(,)*) => {
- $crate::internal::match_tokens(
+ $crate::internal::mismatch_tokens(
&$input,
&$pattern,
- $crate::internal::rs_tokens_to_formatted_string,
+ &$crate::internal::rs_tokens_to_formatted_string,
)
- .expect_err("input unexpectedly matched the pattern");
+ .unwrap();
};
}
@@ -100,8 +100,7 @@
#[macro_export]
macro_rules! assert_ir_not_matches {
($ir:expr, $pattern:expr $(,)*) => {
- $crate::internal::match_ir(&$ir, &$pattern)
- .expect_err("input unexpectedly matched the pattern");
+ $crate::internal::mismatch_ir(&$ir, &$pattern).unwrap();
};
}
@@ -118,13 +117,20 @@
pub use token_stream_printer::{rs_tokens_to_formatted_string, tokens_to_string};
pub fn match_ir(ir: &IR, pattern: &TokenStream) -> Result<()> {
+ match_tokens(&ir_to_token_stream(ir)?, pattern, &ir_to_string)
+ }
+
+ pub fn mismatch_ir(ir: &IR, pattern: &TokenStream) -> Result<()> {
+ mismatch_tokens(&ir_to_token_stream(ir)?, pattern, &ir_to_string)
+ }
+
+ fn ir_to_token_stream(ir: &IR) -> Result<TokenStream> {
// derived debug impl doesn't emit commas after the last element of a group,
// (for example `[a, b, c]`), but rustfmt automatically adds it (`[a, b,
// c,]`). We use rustfmt to format the failure messages. So to make the
// input token stream consistent with failure messages we format the
// input token stream with rustfmt as well.
- let input = ir_to_string(ir.flat_ir_debug_print().parse().unwrap())?.parse().unwrap();
- match_tokens(&input, pattern, ir_to_string)
+ Ok(ir_to_string(ir.flat_ir_debug_print().parse().unwrap())?.parse().unwrap())
}
fn ir_to_string(input: TokenStream) -> Result<String> {
@@ -186,7 +192,7 @@
pub fn match_tokens<ToStringFn>(
input: &TokenStream,
pattern: &TokenStream,
- to_string_fn: ToStringFn,
+ to_string_fn: &ToStringFn,
) -> Result<()>
where
ToStringFn: Fn(TokenStream) -> Result<String>,
@@ -224,6 +230,25 @@
Err(error)
}
+ pub fn mismatch_tokens<ToStringFn>(
+ input: &TokenStream,
+ pattern: &TokenStream,
+ to_string_fn: &ToStringFn,
+ ) -> Result<()>
+ where
+ ToStringFn: Fn(TokenStream) -> Result<String>,
+ {
+ if match_tokens(input, pattern, to_string_fn).is_ok() {
+ let input_string = to_string_fn(input.clone())?;
+ Err(anyhow!(format!(
+ "input unexpectedly matched the pattern. input:\n\n```\n{}\n```",
+ input_string
+ )))
+ } else {
+ Ok(())
+ }
+ }
+
// This implementation uses naive backtracking algorithm that is in the worst
// case O(2^n) in the number of wildcards. In practice this is not so bad
// because wildcards only match their current group, they don't descend into
@@ -456,19 +481,19 @@
}
#[test]
- #[should_panic]
+ #[should_panic(expected = "input:\n\n```\nfn foo(){ }\n")]
fn test_assert_cc_not_matches_panics_on_match() {
assert_cc_not_matches!(quote! { fn foo() {} }, quote! { fn foo() {} });
}
#[test]
- #[should_panic]
+ #[should_panic(expected = "input:\n\n```\nfn foo() {}\n\n```")]
fn test_assert_rs_not_matches_panics_on_match() {
assert_rs_not_matches!(quote! { fn foo() {} }, quote! { fn foo() {} });
}
#[test]
- #[should_panic]
+ #[should_panic(expected = "input:\n\n```\nFlatIR {")]
fn test_assert_ir_not_matches_panics_on_match() {
assert_ir_not_matches!(ir_from_cc("").unwrap(), quote! {items});
}
@@ -529,7 +554,7 @@
match_tokens(
"e! {struct A { int a; int b; };},
"e! {struct B},
- tokens_to_string
+ &tokens_to_string
)
.expect_err("unexpected match")
),
@@ -551,7 +576,7 @@
match_tokens(
"e! {struct A { a: i64, b: i64 }},
"e! {struct B},
- rs_tokens_to_formatted_string
+ &rs_tokens_to_formatted_string
)
.expect_err("unexpected match")
),
@@ -575,7 +600,7 @@
match_tokens(
"e! {fn foo() {}},
"e! {fn foo() {} struct X {}},
- tokens_to_string
+ &tokens_to_string
)
.expect_err("unexpected match")
),
@@ -590,7 +615,7 @@
assert_eq!(
format!(
"{:#}",
- match_tokens("e! {fn foo() ()}, "e! {fn foo() {}}, tokens_to_string)
+ match_tokens("e! {fn foo() ()}, "e! {fn foo() {}}, &tokens_to_string)
.expect_err("unexpected match")
),
"expected delimiter Brace for group '{ }' but got Parenthesis for group '()': \
@@ -607,7 +632,7 @@
match_tokens(
"e! {fn foo() { a: i64, b: i64 }},
"e! {fn foo() { a: i64, c: i64 }},
- tokens_to_string
+ &tokens_to_string
)
.expect_err("unexpected match")
),
@@ -643,7 +668,7 @@
match_tokens(
"e! {impl Drop { fn drop(&mut self) { drop_impl(); }}},
"e! {fn drop(&mut self) {}},
- tokens_to_string
+ &tokens_to_string
)
.expect_err("unexpected match")
),
@@ -657,7 +682,7 @@
match_tokens(
"e! {impl Drop { fn drop(&mut self) { drop_impl1(); drop_impl2(); }}},
"e! {fn drop(&mut self) { drop_impl1(); }},
- tokens_to_string
+ &tokens_to_string
)
.expect_err("unexpected match")
),
@@ -704,7 +729,7 @@
assert_eq!(
format!(
"{:#}",
- match_tokens("e! {[ a b b ]}, "e! { [ a ... c ]}, tokens_to_string)
+ match_tokens("e! {[ a b b ]}, "e! { [ a ... c ]}, &tokens_to_string)
.expect_err("unexpected match")
),
// the error message shows "longer match" with more tokens consumed by the wildcard
@@ -716,7 +741,7 @@
assert_eq!(
format!(
"{:#}",
- match_tokens("e! {[ a b b ]}, "e! { [ a ... b c ]}, tokens_to_string)
+ match_tokens("e! {[ a b b ]}, "e! { [ a ... b c ]}, &tokens_to_string)
.expect_err("unexpected match")
),
// the error message shows "longer match" with branching off the wildcard earlier
