fix: correct error count for cargo check --message-format json

src/cargo/core/compiler/mod.rs

@@ -1742,6 +1742,33 @@ fn on_stderr_line_inner(
         return Ok(true);
     }
 
+    #[derive(serde::Deserialize)]
+    struct CompilerMessage {
+        rendered: String,
+        message: String,
+        level: String,
+        children: Vec<PartialDiagnostic>,
+    }
+
+    // A partial rustfix::diagnostics::Diagnostic. We deserialize only a
+    // subset of the fields because rustc's output can be extremely
+    // deeply nested JSON in pathological cases involving macro
+    // expansion. Rustfix's Diagnostic struct is recursive containing a
+    // field `children: Vec<Self>`, and it can cause deserialization to
+    // hit serde_json's default recursion limit, or overflow the stack
+    // if we turn that off. Cargo only cares about the 1 field listed
+    // here.
+    #[derive(serde::Deserialize)]
+    struct PartialDiagnostic {
+        spans: Vec<PartialDiagnosticSpan>,
+    }
+
+    // A partial rustfix::diagnostics::DiagnosticSpan.
+    #[derive(serde::Deserialize)]
+    struct PartialDiagnosticSpan {
+        suggestion_applicability: Option<Applicability>,
+    }
+
     // Depending on what we're emitting from Cargo itself, we figure out what to
     // do with this JSON message.
     match options.format {
@@ -1755,33 +1782,6 @@ fn on_stderr_line_inner(
             render_diagnostics: true,
             ..
         } => {
-            #[derive(serde::Deserialize)]
-            struct CompilerMessage {
-                rendered: String,
-                message: String,
-                level: String,
-                children: Vec<PartialDiagnostic>,
-            }
-
-            // A partial rustfix::diagnostics::Diagnostic. We deserialize only a
-            // subset of the fields because rustc's output can be extremely
-            // deeply nested JSON in pathological cases involving macro
-            // expansion. Rustfix's Diagnostic struct is recursive containing a
-            // field `children: Vec<Self>`, and it can cause deserialization to
-            // hit serde_json's default recursion limit, or overflow the stack
-            // if we turn that off. Cargo only cares about the 1 field listed
-            // here.
-            #[derive(serde::Deserialize)]
-            struct PartialDiagnostic {
-                spans: Vec<PartialDiagnosticSpan>,
-            }
-
-            // A partial rustfix::diagnostics::DiagnosticSpan.
-            #[derive(serde::Deserialize)]
-            struct PartialDiagnosticSpan {
-                suggestion_applicability: Option<Applicability>,
-            }
-
             if let Ok(mut msg) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
                 if msg.message.starts_with("aborting due to")
                     || msg.message.ends_with("warning emitted")
@@ -1865,12 +1865,30 @@ fn on_stderr_line_inner(
         return Ok(true);
     }
 
-    #[derive(serde::Deserialize)]
-    struct CompilerMessage {
-        level: String,
-    }
-    if let Ok(message) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
-        count_diagnostic(&message.level, options);
+    if let Ok(msg) = serde_json::from_str::<CompilerMessage>(compiler_message.get()) {
+        if msg.message.starts_with("aborting due to")
+            || msg.message.ends_with("warning emitted")
+            || msg.message.ends_with("warnings emitted")
+        {
+            // Skip this line; we'll print our own summary at the end.
+            return Ok(true);
+        }
+        let rendered = msg.rendered;
+        if options.show_diagnostics {
+            let machine_applicable: bool = msg
+                .children
+                .iter()
+                .map(|child| {
+                    child
+                        .spans
+                        .iter()
+                        .filter_map(|span| span.suggestion_applicability)
+                        .any(|app| app == Applicability::MachineApplicable)
+                })
+                .any(|b| b);
+            count_diagnostic(&msg.level, options);
+            state.emit_diag(msg.level, rendered, machine_applicable)?;
+        }
     }
 
     let msg = machine_message::FromCompiler {