From 8cc00103a2c1abc538e092729d2ca97fe71bdae9 Mon Sep 17 00:00:00 2001
From: Markus Olsson <j.markus.olsson@gmail.com>
Date: Fri, 8 Nov 2019 14:37:47 +0100
Subject: [PATCH] Make doubly sure that we have a stream

---
 app/src/lib/git/rebase.ts            |  5 +++++
 app/src/lib/progress/from-process.ts | 10 +++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/app/src/lib/git/rebase.ts b/app/src/lib/git/rebase.ts
index 9847da15105..178dfb6cd7c 100644
--- a/app/src/lib/git/rebase.ts
+++ b/app/src/lib/git/rebase.ts
@@ -323,6 +323,11 @@ function configureOptionsForRebase(
 
   return merge(options, {
     processCallback: (process: ChildProcess) => {
+      // If Node.js encounters a synchronous runtime error while spawning
+      // `stdout` will be undefined and the error will be emitted asynchronously
+      if (!process.stdout) {
+        return
+      }
       const parser = new GitRebaseParser(rebasedCommitCount, totalCommitCount)
 
       // rebase emits progress messages on `stdout`, not `stderr`
diff --git a/app/src/lib/progress/from-process.ts b/app/src/lib/progress/from-process.ts
index f3e30a75fd8..70e69524781 100644
--- a/app/src/lib/progress/from-process.ts
+++ b/app/src/lib/progress/from-process.ts
@@ -77,8 +77,12 @@ function createProgressProcessCallback(
       })
     }
 
-    byline(process.stderr).on('data', (line: string) => {
-      progressCallback(parser.parse(line))
-    })
+    // If Node.js encounters a synchronous runtime error while spawning
+    // `stderr` will be undefined and the error will be emitted asynchronously
+    if (process.stderr) {
+      byline(process.stderr).on('data', (line: string) => {
+        progressCallback(parser.parse(line))
+      })
+    }
   }
 }