[analyzer] Fixes empty linter rules incompatible_lint false negative

Also fixes the message that contained extra quotes around the incompatible lint list even though the parameter itself was "quoted with and", so wrongly `''lint_pos' and 'lint_neg''` instead of `'lint_pos and lint_neg'`.

Fixes: #61500
Change-Id: I60b730aee84eb8d4f229e594aa582aaf00a9c3c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449560
Auto-Submit: Felipe Morschel <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Samuel Rawlins <[email protected]>

Author: FMorschel

pkg/analyzer/lib/src/analysis_options/error/option_codes.g.dart

@@ -315,7 +315,7 @@ class AnalysisOptionsWarningCode extends DiagnosticCodeWithExpectedTypes {
   >
   incompatibleLintIncluded = AnalysisOptionsWarningTemplate(
     'INCOMPATIBLE_LINT',
-    "The rule '{0}' is incompatible with '{1}', which is included from {2} "
+    "The rule '{0}' is incompatible with {1}, which is included from {2} "
         "file{3}.",
     correctionMessage:
         "Try locally disabling all but one of the conflicting rules or "

pkg/analyzer/lib/src/lint/options_rule_validator.dart

@@ -362,6 +362,10 @@ class LinterRuleOptionsValidator extends OptionsValidator {
   ) {
     if (rules is! YamlList &&
         rules is! YamlMap &&
+        // This handles empty keys like
+        // linter:
+        //   rules:
+        (rules is! YamlScalar || rules.value != null) &&
         // We accept 'null' for triggering `INCOMPATIBLE_LINT_INCLUDED`
         rules != null) {
       return;

pkg/analyzer/messages.yaml

@@ -171,7 +171,7 @@ AnalysisOptionsWarningCode:
       int p2: the number of files that include the incompatible rule
       String p3: plural suffix for the word "file"
     sharedName: INCOMPATIBLE_LINT
-    problemMessage: "The rule '#p0' is incompatible with '#p1', which is included from #p2 file#p3."
+    problemMessage: "The rule '#p0' is incompatible with #p1, which is included from #p2 file#p3."
     correctionMessage: "Try locally disabling all but one of the conflicting rules or removing one of the incompatible files."
     hasPublishedDocs: false
     comment: |-

pkg/analyzer/test/src/options/options_rule_validator_test.dart

@@ -185,6 +185,30 @@ include:
     ]);
   }
 
+  Future<void> test_incompatible_multiple_include_noLintMainFile() async {
+    newFile('/included1.yaml', '''
+linter:
+  rules:
+    - rule_neg
+''');
+    newFile('/included2.yaml', '''
+linter:
+  rules:
+    - rule_pos
+''');
+    assertErrors(
+      '''
+include:
+  - included1.yaml
+  - included2.yaml
+
+linter:
+  rules:
+''',
+      [AnalysisOptionsWarningCode.incompatibleLintIncluded],
+    );
+  }
+
   void test_incompatible_noTrigger_invalidMap() {
     newFile('/included.yaml', '''
 linter: