Dont swallow errors when checking existence of a config key

src/cargo/util/config/de.rs

@@ -80,7 +80,7 @@ impl<'de, 'config> de::Deserializer<'de> for Deserializer<'config> {
     where
         V: de::Visitor<'de>,
     {
-        if self.config.has_key(&self.key, self.env_prefix_ok) {
+        if self.config.has_key(&self.key, self.env_prefix_ok)? {
             visitor.visit_some(self)
         } else {
             // Treat missing values as `None`.

src/cargo/util/config/mod.rs

@@ -682,25 +682,25 @@ impl Config {
         }
     }
 
-    fn has_key(&self, key: &ConfigKey, env_prefix_ok: bool) -> bool {
+    /// Check if the [`Config`] contains a given [`ConfigKey`].
+    ///
+    /// See `ConfigMapAccess` for a description of `env_prefix_ok`.
+    fn has_key(&self, key: &ConfigKey, env_prefix_ok: bool) -> CargoResult<bool> {
         if self.env.contains_key(key.as_env_key()) {
-            return true;
+            return Ok(true);
         }
-        // See ConfigMapAccess for a description of this.
         if env_prefix_ok {
             let env_prefix = format!("{}_", key.as_env_key());
             if self.env.keys().any(|k| k.starts_with(&env_prefix)) {
-                return true;
+                return Ok(true);
             }
         }
-        if let Ok(o_cv) = self.get_cv(key) {
-            if o_cv.is_some() {
-                return true;
-            }
+        if self.get_cv(key)?.is_some() {
+            return Ok(true);
         }
         self.check_environment_key_case_mismatch(key);
 
-        false
+        Ok(false)
     }
 
     fn check_environment_key_case_mismatch(&self, key: &ConfigKey) {

tests/testsuite/bad_config.rs

@@ -19,8 +19,8 @@ fn bad1() {
         .with_status(101)
         .with_stderr(
             "\
-[ERROR] invalid configuration for key `target.nonexistent-target`
-expected a table, but found a string for `[..]` in [..]config
+[ERROR] expected table for configuration key `target.nonexistent-target`, \
+but found string in [..]config
 ",
         )
         .run();

tests/testsuite/cargo_alias_config.rs

@@ -21,7 +21,7 @@ fn alias_incorrect_config_type() {
 
     p.cargo("b-cargo-test -v")
         .with_status(101)
-        .with_stderr_contains(
+        .with_stderr(
             "\
 [ERROR] invalid configuration for key `alias.b-cargo-test`
 expected a list, but found a integer for [..]",
@@ -47,9 +47,21 @@ fn alias_malformed_config_string() {
         .with_status(101)
         .with_stderr(
             "\
-[ERROR] no such subcommand: `b-cargo-test`
+[ERROR] could not load Cargo configuration
+
+Caused by:
+  could not parse TOML configuration in `[..]/config`
+
+Caused by:
+  [..]
 
-<tab>View all installed commands with `cargo --list`
+Caused by:
+  TOML parse error at line [..]
+    |
+  3 |                 b-cargo-test = `
+    |                                ^
+  Unexpected ```
+  Expected quoted string
 ",
         )
         .run();
@@ -73,9 +85,19 @@ fn alias_malformed_config_list() {
         .with_status(101)
         .with_stderr(
             "\
-[ERROR] no such subcommand: `b-cargo-test`
+[ERROR] could not load Cargo configuration
+
+Caused by:
+  failed to load TOML configuration from `[..]/config`
+
+Caused by:
+  [..] `alias`
+
+Caused by:
+  [..] `b-cargo-test`
 
-<tab>View all installed commands with `cargo --list`
+Caused by:
+  expected string but found integer in list
 ",
         )
         .run();

tests/testsuite/config.rs

@@ -1074,10 +1074,6 @@ Dotted key `ssl-version` attempted to extend non-table type (string)
 
 ",
     );
-    assert!(config
-        .get::<Option<SslVersionConfig>>("http.ssl-version")
-        .unwrap()
-        .is_none());
 }
 
 #[cargo_test]