From d73bf9c3a084b6a613b3ba47ee816544bcb6b042 Mon Sep 17 00:00:00 2001
From: Deep Singhvi <deep@buildwithfern.com>
Date: Sat, 14 Sep 2024 18:12:11 -0400
Subject: [PATCH] fix(cli): handle consecutive npx install race condition
 (#4643)

---
 packages/cli/cli/src/rerunFernCliAtVersion.ts | 9 ++++++++-
 packages/cli/cli/versions.yml                 | 9 +++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/cli/cli/src/rerunFernCliAtVersion.ts b/packages/cli/cli/src/rerunFernCliAtVersion.ts
index 8d412baa53b..d5de632c9ec 100644
--- a/packages/cli/cli/src/rerunFernCliAtVersion.ts
+++ b/packages/cli/cli/src/rerunFernCliAtVersion.ts
@@ -27,7 +27,7 @@ export async function rerunFernCliAtVersion({
         ].join("\n")
     );
 
-    const { failed } = await loggingExeca(cliContext.logger, "npx", ["--quiet", ...commandLineArgs], {
+    const { failed, stdout, stderr } = await loggingExeca(cliContext.logger, "npx", ["--quiet", ...commandLineArgs], {
         stdio: "inherit",
         reject: false,
         env: {
@@ -35,6 +35,13 @@ export async function rerunFernCliAtVersion({
             [FERN_CWD_ENV_VAR]: process.env[FERN_CWD_ENV_VAR] ?? process.cwd()
         }
     });
+    if (stdout.includes("code EEXIST") || stderr.includes("code EEXIST")) {
+        // try again if there is a npx conflict
+        return await rerunFernCliAtVersion({
+            version,
+            cliContext
+        });
+    }
 
     if (failed) {
         cliContext.failWithoutThrowing();
diff --git a/packages/cli/cli/versions.yml b/packages/cli/cli/versions.yml
index 456f724c1a0..218aa47024e 100644
--- a/packages/cli/cli/versions.yml
+++ b/packages/cli/cli/versions.yml
@@ -1,3 +1,12 @@
+- changelogEntry:
+  - summary: |
+      The Fern CLI now safely handles a npx file exists error by retrying the command on failure. 
+      This error typically happens when two or more instances of the Fern CLI are running `npx`
+      at the same time. 
+    type: fix
+  irVersion: 53
+  version: 0.41.14-rc0
+
 - changelogEntry:
   - summary: |
       `fern generate --local` no longer crashes on large API Definitions because we