fix: silent false success when git is not present

Add callback function and error check to `execFile`.

Fixes conventional-changelog/commitlint#2136

Author: thesmiley1

packages/git-raw-commits/index.js

@@ -53,38 +53,31 @@ function gitRawCommits (rawGitOpts, rawExecOpts) {
     gitOpts.debug('Your git-log command is:\ngit ' + args.join(' '))
   }
 
-  let isError = false
-
   const child = execFile('git', args, {
     cwd: execOpts.cwd,
     maxBuffer: Infinity
+  }, function (err) {
+    if (err != null) {
+      readable.emit('error', err)
+    }
+
+    readable.emit('close')
   })
 
   child.stdout
     .pipe(split(DELIMITER + '\n'))
     .pipe(through(function (chunk, enc, cb) {
       readable.push(chunk)
-      isError = false
 
       cb()
     }, function (cb) {
       setImmediate(function () {
-        if (!isError) {
-          readable.push(null)
-          readable.emit('close')
-        }
+        readable.push(null)
 
         cb()
       })
     }))
 
-  child.stderr
-    .pipe(through.obj(function (chunk) {
-      isError = true
-      readable.emit('error', new Error(chunk))
-      readable.emit('close')
-    }))
-
   return readable
 }
 

packages/git-raw-commits/test.js

@@ -29,8 +29,6 @@ describe('git-raw-commits', function () {
       })
       .pipe(through(function () {
         done('should error')
-      }, function () {
-        done('should error')
       }))
   })
 
@@ -192,4 +190,24 @@ describe('git-raw-commits', function () {
         done()
       }))
   })
+
+  it('should emit an error if git is not available', function (done) {
+    try {
+      var path = process.env.PATH
+      process.env.PATH = ''
+
+      gitRawCommits()
+        .on('error', function (err) {
+          expect(err).to.be.ok // eslint-disable-line no-unused-expressions
+          done()
+        })
+        .pipe(through(function () {
+          done('should error')
+        }, function () {
+          done('should error')
+        }))
+    } finally {
+      process.env.PATH = path
+    }
+  })
 })