Merge pull request #7002 from DoTuanAnh2k1/check-non-mutating-with-config-emit

Keep --check non-mutating when emit_mode is set via --config

Author: ytmimi

src/bin/main.rs

@@ -630,6 +630,19 @@ impl GetOptsOptions {
             options.emit_mode = Some(emit_mode_from_emit_str(emit_str)?);
         }
 
+        if options.inline_config.contains_key("emit_mode") {
+            if options.check {
+                return Err(format_err!(
+                    "Invalid to use `--config=emit_mode=<mode>` and `--check`"
+                ));
+            }
+            if options.emit_mode.is_some() {
+                return Err(format_err!(
+                    "Invalid to use `--config=emit_mode=<mode>` and `--emit`"
+                ));
+            }
+        }
+
         if let Some(ref edition_str) = matches.opt_str("edition") {
             options.edition = Some(edition_from_edition_str(edition_str)?);
         }
@@ -826,6 +839,37 @@ mod test {
         assert_eq!(config.style_edition(), StyleEdition::Edition2024);
     }
 
+    #[test]
+    fn emit_mode_from_inline_config_is_rejected() {
+        // Regression for #6999.
+        let emit_modes = [
+            "Files",
+            "Stdout",
+            "Coverage",
+            "Checkstyle",
+            "Json",
+            "ModifiedLines",
+            "Diff",
+        ];
+        for mode in emit_modes {
+            let config = format!("emit_mode={mode}");
+
+            let matches = make_opts().parse(["--check", "--config", &config]).unwrap();
+            assert!(
+                GetOptsOptions::from_matches(&matches).is_err(),
+                "`--check` with `--config={config}` should be rejected"
+            );
+
+            let matches = make_opts()
+                .parse(["--emit", "stdout", "--config", &config])
+                .unwrap();
+            assert!(
+                GetOptsOptions::from_matches(&matches).is_err(),
+                "`--emit` with `--config={config}` should be rejected"
+            );
+        }
+    }
+
     #[nightly_only_test]
     #[test]
     fn version_config_file_sets_style_edition_override_correctly() {