Fix: off-by-one error in eslint-disable comment checking

lib/linter.js

@@ -404,7 +404,7 @@ function modifyConfigsFromComments(filename, ast, config, linterContext) {
  * Check if message of rule with ruleId should be ignored in location
  * @param  {Object[]} reportingConfig  Collection of ignore records
  * @param  {string} ruleId   Id of rule
- * @param  {Object} location Location of message
+ * @param  {Object} location 1-indexed location of message
  * @returns {boolean}          True if message should be ignored, false otherwise
  */
 function isDisabledByReportingConfig(reportingConfig, ruleId, location) {
@@ -414,8 +414,8 @@ function isDisabledByReportingConfig(reportingConfig, ruleId, location) {
         const ignore = reportingConfig[i];
 
         if ((!ignore.rule || ignore.rule === ruleId) &&
-            (location.line > ignore.start.line || (location.line === ignore.start.line && location.column >= ignore.start.column)) &&
-            (!ignore.end || (location.line < ignore.end.line || (location.line === ignore.end.line && location.column <= ignore.end.column)))) {
+            (location.line > ignore.start.line || (location.line === ignore.start.line && location.column > ignore.start.column)) &&
+            (!ignore.end || (location.line < ignore.end.line || (location.line === ignore.end.line && location.column - 1 <= ignore.end.column)))) {
             return true;
         }
     }

tests/lib/linter.js

@@ -1548,6 +1548,33 @@ describe("Linter", () => {
             assert.equal(messages.length, 0);
         });
 
+        it("should report a violation when the report is right before the comment", () => {
+            const code = " /* eslint-disable */ ";
+
+            linter.defineRule("checker", context => ({
+                Program() {
+                    context.report({ loc: { line: 1, column: 0 }, message: "foo" });
+                }
+            }));
+            const problems = linter.verify(code, { rules: { checker: "error" } });
+
+            assert.strictEqual(problems.length, 1);
+            assert.strictEqual(problems[0].message, "foo");
+        });
+
+        it("should not report a violation when the report is right at the start of the comment", () => {
+            const code = " /* eslint-disable */ ";
+
+            linter.defineRule("checker", context => ({
+                Program() {
+                    context.report({ loc: { line: 1, column: 1 }, message: "foo" });
+                }
+            }));
+            const problems = linter.verify(code, { rules: { checker: "error" } });
+
+            assert.strictEqual(problems.length, 0);
+        });
+
         it("rules should not change initial config", () => {
             const config = { rules: { "test-plugin/test-rule": 2 } };
             const codeA = "/*eslint test-plugin/test-rule: 0*/ var a = \"trigger violation\";";