Remove TOML incompatibility hacks

src/cargo/util/toml/mod.rs

@@ -150,50 +150,10 @@ fn do_read_manifest(
 /// The purpose of this wrapper is to detect invalid TOML which was previously
 /// accepted and display a warning to the user in that case. The `file` and `config`
 /// parameters are only used by this fallback path.
-pub fn parse(toml: &str, file: &Path, config: &Config) -> CargoResult<toml::Value> {
-    let first_error = match toml.parse() {
-        Ok(ret) => return Ok(ret),
-        Err(e) => e,
-    };
-
-    let mut second_parser = toml::de::Deserializer::new(toml);
-    second_parser.set_require_newline_after_table(false);
-    if let Ok(ret) = toml::Value::deserialize(&mut second_parser) {
-        let msg = format!(
-            "\
-TOML file found which contains invalid syntax and will soon not parse
-at `{}`.
-
-The TOML spec requires newlines after table definitions (e.g., `[a] b = 1` is
-invalid), but this file has a table header which does not have a newline after
-it. A newline needs to be added and this warning will soon become a hard error
-in the future.",
-            file.display()
-        );
-        config.shell().warn(&msg)?;
-        return Ok(ret);
-    }
-
-    let mut third_parser = toml::de::Deserializer::new(toml);
-    third_parser.set_allow_duplicate_after_longer_table(true);
-    if let Ok(ret) = toml::Value::deserialize(&mut third_parser) {
-        let msg = format!(
-            "\
-TOML file found which contains invalid syntax and will soon not parse
-at `{}`.
-
-The TOML spec requires that each table header is defined at most once, but
-historical versions of Cargo have erroneously accepted this file. The table
-definitions will need to be merged together with one table header to proceed,
-and this will become a hard error in the future.",
-            file.display()
-        );
-        config.shell().warn(&msg)?;
-        return Ok(ret);
-    }
-
-    let first_error = anyhow::Error::from(first_error);
-    Err(first_error.context("could not parse input as TOML"))
+pub fn parse(toml: &str, _file: &Path, _config: &Config) -> CargoResult<toml::Value> {
+    // At the moment, no compatibility checks are needed.
+    toml.parse()
+        .map_err(|e| anyhow::Error::from(e).context("could not parse input as TOML"))
 }
 
 type TomlLibTarget = TomlTarget;

tests/testsuite/bad_config.rs

@@ -773,26 +773,15 @@ to use. This will be considered an error in future versions
 }
 
 #[cargo_test]
-fn invalid_toml_historically_allowed_is_warned() {
+fn invalid_toml_historically_allowed_fails() {
     let p = project()
         .file(".cargo/config", "[bar] baz = 2")
         .file("src/main.rs", "fn main() {}")
         .build();
 
     p.cargo("build")
-        .with_stderr(
-            "\
-warning: TOML file found which contains invalid syntax and will soon not parse
-at `[..]config`.
-
-The TOML spec requires newlines after table definitions (e.g., `[a] b = 1` is
-invalid), but this file has a table header which does not have a newline after
-it. A newline needs to be added and this warning will soon become a hard error
-in the future.
-[COMPILING] foo v0.0.1 ([..])
-[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-",
-        )
+        .with_status(101)
+        .with_stderr_contains("  expected newline, found an identifier at line 1 column 7")
         .run();
 }