feat: Fix or disable rules re babel#90

- Disable `array-callback-return`
- Disable `react/require-render-return`
- Monkeypatch `fp/no-nil`

Re wcjohnson/lightscript#90

README.md

@@ -31,7 +31,7 @@ Issues: https://github.com/wcjohnson/lightscript/issues
     $ (npm bin)/eslint --ext .js,.lsc src/
     ```
 
-`@lightscript/eslint-plugin` is fully compatible with all other ESLint plugins and can lint JavaScript as well as LightScript code.
+`@lightscript/eslint-plugin` is compatible with most other ESLint plugins and can lint JavaScript as well as LightScript code.
 
 ## The Details
 
@@ -155,7 +155,16 @@ Warn when a `,` is unnecessary according to LightScript list separator rules.
 If ESLint is hoisted outside of the root `node_modules` folder of your package, it will not be able to find the plugin and you will encounter "can't find plugin" errors. To fix this, use the `nohoist` option of your monorepo tool to ensure ESLint is not hoisted out of your package.
 
 - `no-extra-semi` rule:
-The `no-extra-semi` rule has a bug when iterating over whiteblock code. When linting LightScript files, this rule is automatically disabled. We recommend the `@lightscript/unnecessary-semi` rule instead.
+When linting LightScript files, this rule is automatically disabled. We recommend the `@lightscript/unnecessary-semi` rule instead.
+
+- `array-callback-return` rule:
+When linting LightScript files, this rule is automatically disabled. This rule
+is broken pending changes to ESLint's code path analysis; see
+[this issue](https://github.com/eslint/eslint/issues/10823)
+
+- `react/require-render-return` rule:
+When linting LightScript files, this rule is automatically disabled. Because
+of LightScript's implicit returns, this rule is almost always superfluous.
 
 Flow:
 > Check out [eslint-plugin-flowtype](https://github.com/gajus/eslint-plugin-flowtype): An `eslint` plugin that makes flow type annotations global variables and marks declarations as used. Solves the problem of false positives with `no-undef` and `no-unused-vars`.

src/rules/patched.lsc

@@ -1,6 +1,7 @@
 // Patches for core ESLint rules
 import noUseBeforeDefine from './patched/noUseBeforeDefine'
 import restSpreadSpacing from './patched/rest-spread-spacing'
+import fpNoNil from './patched/fp-no-nil'
 
 patchedRules = {}
 
@@ -33,4 +34,7 @@ patches = {
   "no-use-before-define": patchIfLsc(noUseBeforeDefine)
   "rest-spread-spacing": patchIfLsc(restSpreadSpacing)
   "no-extra-semi": patchIfLsc(nullRule)
+  "array-callback-return": patchIfLsc(nullRule)
+  "fp/no-nil": patchIfLsc(fpNoNil)
+  "react/require-render-return": patchIfLsc(nullRule)
 }

src/rules/patched/fp-no-nil.js

@@ -0,0 +1,90 @@
+'use strict';
+
+function isComparison(node) {
+  return node.parent &&
+    node.parent.type === 'BinaryExpression' &&
+    (['==', '!=', '===', '!=='].indexOf(node.parent.operator) > -1)
+}
+
+function reportUseOutsideOfComparison(context, node) {
+  if (!isComparison(node)) {
+    context.report({
+      node,
+      message: 'Unallowed use of `null` or `undefined`'
+    });
+  }
+}
+
+function endsWithReturnStatement(body) {
+  return (
+    body.length > 0 &&
+    body[body.length - 1].type === 'ReturnStatement'
+  )
+}
+
+const create = function (context) {
+  function reportFunctions(node) {
+    // LSC: if function has an implicit return, good enough for me
+    if( context.parserServices.getImplicitlyReturnedNodes(node) ) {
+      return;
+    }
+
+    if (node.body.type === 'BlockStatement' &&
+      !endsWithReturnStatement(node.body.body)
+    ) {
+      context.report({
+        node,
+        message: 'Function must end with a return statement, so that it doesn\'t return `undefined`'
+      });
+    }
+  }
+
+  const visitor = {
+    Literal(node) {
+      if (node.value === null) {
+        reportUseOutsideOfComparison(context, node);
+      }
+    },
+    Identifier(node) {
+      if (node.name === 'undefined') {
+        reportUseOutsideOfComparison(context, node);
+      }
+    },
+    VariableDeclarator(node) {
+      if (node.init === null) {
+        context.report({
+          node,
+          message: 'Variable must be initialized, so that it doesn\'t evaluate to `undefined`'
+        });
+      }
+    },
+    ReturnStatement(node) {
+      if (node.argument === null) {
+        context.report({
+          node,
+          message: 'Return statement must return an explicit value, so that it doesn\'t evaluate to `undefined`'
+        });
+      }
+    },
+    ArrowFunctionExpression: reportFunctions,
+    FunctionDeclaration: reportFunctions,
+    FunctionExpression: reportFunctions
+  };
+
+  for(const k of context.parserServices.aliasesFor("Function")) {
+    visitor[k] = reportFunctions;
+  }
+
+  return visitor;
+};
+
+module.exports = {
+  create,
+  meta: {
+    docs: {
+      description: 'Forbid the use of `null` and `undefined`.',
+      recommended: 'error',
+      url: 'https://github.com/jfmengels/eslint-plugin-fp/tree/master/docs/rules/no-nil.md'
+    }
+  }
+};

test/fixtures/lightscript/brokenRules/regression/#90/array-callback-return/output.json

@@ -1,3 +1 @@
-[
-  "3:11 Expected to return a value in arrow function. array-callback-return"
-]
+[]

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/negative-oneline/input.js

@@ -0,0 +1,2 @@
+f() -> 1
+f()

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/negative-oneline/output.json

@@ -0,0 +1 @@
+[]

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/negative-twoline/input.js

@@ -0,0 +1,3 @@
+f() ->
+  1
+f()

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/negative-twoline/output.json

@@ -0,0 +1 @@
+[]

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/positive/input.js

@@ -0,0 +1,3 @@
+f() ->
+  for x in []: x
+f()

test/fixtures/lightscript/brokenRules/regression/#90/fp-no-nil/positive/output.json

@@ -0,0 +1,3 @@
+[
+  "1:1 Function must end with a return statement, so that it doesn't return `undefined` fp/no-nil"
+]

test/fixtures/lightscript/brokenRules/regression/#90/options.json

@@ -4,6 +4,7 @@
     "no-unused-vars": 1,
     "no-undef": 1,
     "array-callback-return": 1,
-    "react/require-render-return": 1
+    "react/require-render-return": 1,
+    "fp/no-nil": 1
   }
 }

test/fixtures/lightscript/brokenRules/regression/#90/require-render-return/output.json

@@ -1,3 +1 @@
-[
-  "3:1 Your render method should have return statement react/require-render-return"
-]
+[]