findConfigurationPath: search for tslint.json up to root (#3309)

[bugfix] fixed regression where the lookup of `tslint.json` stopped at the current directory.
Fixes: #3050

src/configuration.ts

@@ -140,9 +140,9 @@ export function findConfigurationPath(suppliedConfigFilePath: string | null, inp
         }
 
         // search for tslint.json from input file location
-        let configFilePath = findup(CONFIG_FILENAME, inputFilePath!);
+        let configFilePath = findup(CONFIG_FILENAME, path.resolve(inputFilePath!));
         if (configFilePath !== undefined) {
-            return path.resolve(configFilePath);
+            return configFilePath;
         }
 
         // search for tslint.json in home directory

test/executable/executableTests.ts

@@ -218,6 +218,20 @@ describe("Executable", function(this: Mocha.ISuiteCallbackContext) {
         });
     });
 
+    it("finds configuration above current directory", (done) => {
+        execCli(
+            ["index.test.ts"],
+            {
+                cwd: "./test/files/config-findup/no-config",
+            },
+            (err) => {
+                assert.isNotNull(err, "process should exit with an error");
+                assert.equal(err.code, 2, "exit code should be 2");
+                done();
+            },
+        );
+    });
+
     describe("--fix flag", () => {
         it("fixes multiple rules without overwriting each other", (done) => {
             const tempFile = path.relative(process.cwd(), createTempFile("ts"));

test/files/config-findup/no-config/index.test.ts

@@ -0,0 +1 @@
+'';

test/files/config-findup/tslint.json

@@ -1 +1,5 @@
-{}
+{
+  "rules": {
+    "quotemark": true
+  }
+}