fix: stream in error without error content handling (#662)

Co-authored-by: Sebastien <[email protected]>

__mocks__/child_process.js

@@ -17,7 +17,6 @@ childProcess.spawn.mockImplementation(() => {
         this.push(output.pop().join(EOL))
       }
       this.push(null)
-      mock.emit('close')
     },
   })
   mock.stderr = new Readable({
@@ -26,9 +25,9 @@ childProcess.spawn.mockImplementation(() => {
         this.push('error')
       }
       this.push(null)
-      mock.emit('close')
     },
   })
+  setTimeout(() => mock.emit('close', error ? 1 : 0), 0)
   return mock
 })
 

__tests__/unit/lib/utils/childProcessUtils.test.js

@@ -9,27 +9,30 @@ const {
 const { EventEmitter, Readable } = require('stream')
 const { sep } = require('path')
 
+const arrangeStream = (data, error, isError) => {
+  const getReadable = content => {
+    return new Readable({
+      read() {
+        if (content) this.push(content)
+        this.push(null)
+      },
+    })
+  }
+  const stream = new EventEmitter()
+  stream.stdout = getReadable(data)
+  stream.stderr = getReadable(error)
+  setTimeout(() => stream.emit('close', isError ? 1 : 0), 0)
+  return stream
+}
+
 describe('childProcessUtils', () => {
   describe('getStreamContent', () => {
     describe.each([Buffer.from('text'), 'text'])(
       'when called with stream of %o',
       content => {
         it('returns Buffer', async () => {
           // Arrange
-          const stream = new EventEmitter()
-          stream.stdout = new Readable({
-            read() {
-              this.push(content)
-              this.push(null)
-              stream.emit('close')
-            },
-          })
-          stream.stderr = new Readable({
-            read() {
-              this.push(null)
-              stream.emit('close')
-            },
-          })
+          const stream = arrangeStream(content, null, false)
 
           // Act
           const result = await getStreamContent(stream)
@@ -40,25 +43,12 @@ describe('childProcessUtils', () => {
       }
     )
 
-    describe('when stream emit error', () => {
+    describe('when stream emits error', () => {
       it('throws the error', async () => {
         // Arrange
         expect.assertions(1)
-        const stream = new EventEmitter()
-        stream.stdout = new Readable({
-          read() {
-            this.push(null)
-            stream.emit('close')
-          },
-        })
 
-        stream.stderr = new Readable({
-          read() {
-            this.push('error')
-            this.push(null)
-            stream.emit('close')
-          },
-        })
+        const stream = arrangeStream('irrelevant std out output', 'error', true)
 
         // Act
         try {
@@ -70,6 +60,24 @@ describe('childProcessUtils', () => {
         }
       })
     })
+
+    describe('when stream emits error but no stderr output', () => {
+      it('throws an empty error', async () => {
+        // Arrange
+        expect.assertions(1)
+
+        const stream = arrangeStream('irrelevant std out output', null, true)
+
+        // Act
+        try {
+          await getStreamContent(stream)
+
+          // Assert
+        } catch (error) {
+          expect(error.message).toEqual('')
+        }
+      })
+    })
   })
   describe('linify', () => {
     describe('when called with lines', () => {

package.json

@@ -74,16 +74,16 @@
     "@stryker-mutator/jest-runner": "^7.1.1",
     "@swc/core": "^1.3.71",
     "@types/mocha": "^10.0.1",
-    "@types/node": "^20.4.4",
+    "@types/node": "^20.4.5",
     "@typescript-eslint/parser": "^6.2.0",
     "benchmark": "^2.1.4",
     "chai": "^4.3.7",
     "depcheck": "^1.4.3",
     "eslint": "^8.45.0",
-    "eslint-config-prettier": "^8.8.0",
+    "eslint-config-prettier": "^8.9.0",
     "eslint-plugin-prettier": "^5.0.0",
     "husky": "^8.0.3",
-    "jest": "^29.6.1",
+    "jest": "^29.6.2",
     "lint-staged": "^13.2.3",
     "mocha": "^10.2.0",
     "nyc": "^15.1.0",

src/utils/childProcessUtils.js

@@ -34,18 +34,27 @@ async function* linify(stream) {
 }
 
 const getStreamContent = async stream => {
-  const content = []
-  for await (const chunk of stream.stdout) {
-    content.push(chunk)
-  }
-  const error = []
-  for await (const chunk of stream.stderr) {
-    error.push(chunk)
-  }
-  if (error.length > 0) {
-    throw new Error(error.join(''))
-  }
-  return Buffer.concat(content)
+  return new Promise((resolve, reject) => {
+    const content = []
+    const error = []
+
+    stream.stdout.on('data', data => {
+      content.push(data)
+    })
+
+    stream.stderr.setEncoding('utf8')
+    stream.stderr.on('data', data => {
+      error.push(data.toString())
+    })
+
+    stream.on('close', code => {
+      if (code !== 0) {
+        reject(new Error(error.join('')))
+      }
+
+      resolve(Buffer.concat(content))
+    })
+  })
 }
 
 module.exports.EOLRegex = EOLRegex