Repository: eslint/eslint (js)

Issue:
ESLint crash with prefer-object-spread
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**Tell us about your environment**

* **ESLint Version:** 5.2.0
* **Node Version:** v10.7.0
* **npm Version:** 6.1.0

**What parser (default, Babel-ESLint, etc.) are you using?**
I can reproduce this with the default parser, and with babel-eslint. I haven't tried other alternatives.

**Please show your full configuration:**

<details>
<summary>Configuration</summary>

<!-- Paste your configuration below: -->
```js
{
  "root": true,
  "rules": {
    "prefer-object-spread": 1
  }
}
```

</details>

**What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.**

<!-- Paste the source code below: -->
```js
Object.assign({
});
```

<!-- Paste the command you used to run ESLint: -->
```bash
./node_modules/.bin/eslint src
```

**What did you expect to happen?**
```
.../src/test.js
1:1  warning  Use an object literal instead of `Object.assign`. eg: `{ foo: bar }`  prefer-object-spread

✖ 1 problem (0 errors, 1 warning)
  0 errors and 1 warning potentially fixable with the `--fix` option.
```
**What actually happened? Please include the actual, raw output from ESLint.**
```
Fix objects must not be overlapped in a report.
AssertionError [ERR_ASSERTION]: Fix objects must not be overlapped in a report.
    at mergeFixes (/mnt/c/test/node_modules/eslint/lib/report-translator.js:150:9)
    at normalizeFixes (/mnt/c/test/node_modules/eslint/lib/report-translator.js:180:16)
    at args (/mnt/c/test/node_modules/eslint/lib/report-translator.js:278:18)
    at Object.report (/mnt/c/test/node_modules/eslint/lib/linter.js:830:41)
    at Program (/mnt/c/test/node_modules/eslint/lib/rules/prefer-object-spread.js:249:33)
    at listeners.(anonymous function).forEach.listener (/mnt/c/test/node_modules/eslint/lib/util/safe-emitter.js:45:58)
    at Array.forEach (<anonymous>)
    at Object.emit (/mnt/c/test/node_modules/eslint/lib/util/safe-emitter.js:45:38)
    at NodeEventGenerator.applySelector (/mnt/c/test/node_modules/eslint/lib/util/node-event-generator.js:251:26)
    at NodeEventGenerator.applySelectors (/mnt/c/test/node_modules/eslint/lib/util/node-event-generator.js:280:22)
```

Pull request description:
Fix: ESLint crash with prefer-object-spread (fixes #10646)
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**What is the purpose of this pull request? (put an "X" next to item)**

[ ] Documentation update
[x] Bug fix ([template](https://raw.githubusercontent.com/eslint/eslint/master/templates/bug-report.md))
[ ] New rule ([template](https://raw.githubusercontent.com/eslint/eslint/master/templates/rule-proposal.md))
[ ] Changes an existing rule ([template](https://raw.githubusercontent.com/eslint/eslint/master/templates/rule-change-proposal.md))
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

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**What changes did you make? (Give an overview)**
fixes #10646 

**Is there anything you'd like reviewers to focus on?**
no



Patch:
diff --git a/Makefile.js b/Makefile.js
index 9c48620ef..cd756a746 100644
--- a/Makefile.js
+++ b/Makefile.js
@@ -684,7 +684,7 @@ target.gensite = function(prereleaseVersion) {
     const rules = require(".").linter.getRules();
 
     const RECOMMENDED_TEXT = "\n\n(recommended) The `\"extends\": \"eslint:recommended\"` property in a configuration file enables this rule.";
-    const FIXABLE_TEXT = "\n\n(fixable) The `--fix` option on the [command line](../user-guide/command-line-interface#fix) can automatically fix some of the problems reported by this rule.";
+    const FIXABLE_TEXT = "\n\n(fixable) The `--fix` option on the [command line](../user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.";
 
     // 4. Loop through all files in temporary directory
     process.stdout.write("> Updating files (Steps 4-9): 0/... - ...\r");
diff --git a/docs/developer-guide/nodejs-api.md b/docs/developer-guide/nodejs-api.md
index e56fd5789..2e3390b93 100644
--- a/docs/developer-guide/nodejs-api.md
+++ b/docs/developer-guide/nodejs-api.md
@@ -330,7 +330,7 @@ var CLIEngine = require("eslint").CLIEngine;
 The `CLIEngine` is a constructor, and you can create a new instance by passing in the options you want to use. The available options are:
 
 * `allowInlineConfig` - Set to `false` to disable the use of configuration comments (such as `/*eslint-disable*/`). Corresponds to `--no-inline-config`.
-* `baseConfig` - Set to false to disable use of base config. Could be set to an object to override default base config as well.
+* `baseConfig` - Can optionally be set to a config object. This will used as a default config, and will be merged with any configuration defined in `.eslintrc.*` files, with the `.eslintrc.*` files having precedence.
 * `cache` - Operate only on changed files (default: `false`). Corresponds to `--cache`.
 * `cacheFile` - Name of the file where the cache will be stored (default: `.eslintcache`). Corresponds to `--cache-file`. Deprecated: use `cacheLocation` instead.
 * `cacheLocation` - Name of the file or directory where the cache will be stored (default: `.eslintcache`). Corresponds to `--cache-location`.
diff --git a/docs/rules/no-prototype-builtins.md b/docs/rules/no-prototype-builtins.md
index 1694356a3..e2dd4f5b9 100644
--- a/docs/rules/no-prototype-builtins.md
+++ b/docs/rules/no-prototype-builtins.md
@@ -1,6 +1,6 @@
 # Disallow use of Object.prototypes builtins directly (no-prototype-builtins)
 
-In ECMAScript 5.1, `Object.create` was added, which enables the creation of objects with a specified `[[Prototype]]`. `Object.create(null)` is a common pattern used to create objects that will be used as a Map. This can lead to errors when it is assumed that objects will have properties from `Object.prototype`. This rule prevents calling `Object.prototype` methods directly from an object.
+In ECMAScript 5.1, `Object.create` was added, which enables the creation of objects with a specified `[[Prototype]]`. `Object.create(null)` is a common pattern used to create objects that will be used as a Map. This can lead to errors when it is assumed that objects will have properties from `Object.prototype`. This rule prevents calling some `Object.prototype` methods directly from an object.
 
 ## Rule Details
 
diff --git a/lib/cli-engine.js b/lib/cli-engine.js
index 8442de2de..aa0f5521c 100644
--- a/lib/cli-engine.js
+++ b/lib/cli-engine.js
@@ -41,7 +41,7 @@ const resolver = new ModuleResolver();
  * The options to configure a CLI engine with.
  * @typedef {Object} CLIEngineOptions
  * @property {boolean} allowInlineConfig Enable or disable inline configuration comments.
- * @property {boolean|Object} baseConfig Base config object. True enables recommend rules and environments.
+ * @property {Object} baseConfig Base config object, extended by all configs used with this CLIEngine instance
  * @property {boolean} cache Enable result caching.
  * @property {string} cacheLocation The cache file to use instead of .eslintcache.
  * @property {string} configFile The configuration file to use.
diff --git a/lib/rules/prefer-object-spread.js b/lib/rules/prefer-object-spread.js
index 6ddb66540..3df16b7ae 100644
--- a/lib/rules/prefer-object-spread.js
+++ b/lib/rules/prefer-object-spread.js
@@ -180,8 +180,14 @@ function defineFixer(node, sourceCode) {
                 for (const innerParen of innerParens) {
                     yield fixer.remove(innerParen);
                 }
-                yield fixer.removeRange([left.range[0], getEndWithSpaces(left, sourceCode)]);
-                yield fixer.removeRange([getStartWithSpaces(right, sourceCode), right.range[1]]);
+                const leftRange = [left.range[0], getEndWithSpaces(left, sourceCode)];
+                const rightRange = [
+                    Math.max(getStartWithSpaces(right, sourceCode), leftRange[1]), // Ensure ranges don't overlap
+                    right.range[1]
+                ];
+
+                yield fixer.removeRange(leftRange);
+                yield fixer.removeRange(rightRange);
 
                 // Remove the comma of this argument if it's duplication.
                 if (


Test patch:
diff --git a/tests/lib/rules/prefer-object-spread.js b/tests/lib/rules/prefer-object-spread.js
index 7790f8796..acac665e5 100644
--- a/tests/lib/rules/prefer-object-spread.js
+++ b/tests/lib/rules/prefer-object-spread.js
@@ -808,6 +808,32 @@ ruleTester.run("prefer-object-spread", rule, {
                     column: 29
                 }
             ]
+        },
+
+        // https://github.com/eslint/eslint/issues/10646
+        {
+            code: "Object.assign({ });",
+            output: "({});",
+            errors: [
+                {
+                    messageId: "useLiteralMessage",
+                    type: "CallExpression",
+                    line: 1,
+                    column: 1
+                }
+            ]
+        },
+        {
+            code: "Object.assign({\n});",
+            output: "({});",
+            errors: [
+                {
+                    messageId: "useLiteralMessage",
+                    type: "CallExpression",
+                    line: 1,
+                    column: 1
+                }
+            ]
         }
     ]
 });