fix: unsafe catch unwinding case, simple noop catch handler

Author: jedwards1211

src/util/unwindCatch.ts

@@ -2,7 +2,7 @@ import * as t from '@babel/types'
 import { NodePath } from '@babel/traverse'
 
 import getPreceedingLink from './getPreceedingLink'
-import { isNullish } from './predicates'
+import { isNullish, isPromiseMethodCall } from './predicates'
 import canUnwindAsIs from './canUnwindAsIs'
 import replaceLink from './replaceLink'
 import renameBoundIdentifiers from './renameBoundIdentifiers'
@@ -39,16 +39,17 @@ export default function unwindCatch(
     ) as any
   }
   const handlerFunction = handler as NodePath<t.Function>
-  handlerFunction.node.async = true
   const body = handlerFunction.get('body')
   if (
     body.isBlockStatement() &&
-    !canUnwindAsIs(link) &&
-    !convertConditionalReturns(body)
+    ((body.node.body.length === 0 &&
+      !isPromiseMethodCall(getPreceedingLink(link).node)) ||
+      (!canUnwindAsIs(link) && !convertConditionalReturns(body)))
   ) {
-    return getPreceedingLink(link)
+    return []
   }
 
+  handlerFunction.node.async = true
   const input = handlerFunction.get('params')[0]
   if (input) renameBoundIdentifiers(input, link.scope)
   const inputNode = input?.node

test/fixtures/bugs_Sequelize.transaction.ts

@@ -54,12 +54,7 @@ class Sequelize {
       } catch (err) {
         // Rollback transaction if not already finished (commit, rollback, etc)
         // and reject with original error (ignore any error in rollback)
-        if (!transaction.finished) {
-          try {
-            await transaction.rollback();
-          } catch (err0) {
-          }
-        }
+        if (!transaction.finished) await transaction.rollback().catch(() => {});
         throw err;
       }
     });

test/fixtures/catch_Swallow.ts

@@ -0,0 +1,13 @@
+export const input = `
+function foo() {
+  return baz.catch(() => {})
+}
+`
+
+export const options = {}
+
+export const expected = `
+async function foo() {
+  return baz.catch(() => {})
+}
+`

test/fixtures/catch_handlersThatCantBeUnwound.ts

@@ -39,31 +39,31 @@ export const options = {}
 
 export const expected = `
 async function foo() {
-  return String(await bar.catch(async baz => {
+  return String(await bar.catch(baz => {
     switch (baz) {
       case 2: return
     }
     console.log('test')
   }))
 }
 async function bar() {
-  return String(await a.catch(async b => {
+  return String(await a.catch(b => {
     for (const i of [1, 2, 3]) {
       return
     }
     console.log('test')
   }))
 }
 async function qux() {
-  return String(await a.catch(async b => {
+  return String(await a.catch(b => {
     while (i) {
       return
     }
     console.log('test')
   }))
 }
 async function baz() {
-  return String(await a.catch(async b => {
+  return String(await a.catch(b => {
     if (a) {
       if (b) {
         return