From 383652163b5729859f9721edb0faf08fea297b9d Mon Sep 17 00:00:00 2001
From: Dustin Schau <dustinschau@gmail.com>
Date: Mon, 12 Feb 2018 13:01:32 -0800
Subject: [PATCH] fix: dasherize after leading underscore

---
 packages/gatsby/src/schema/__tests__/create-key.js | 12 +++++++++---
 packages/gatsby/src/schema/create-key.js           |  4 ++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/packages/gatsby/src/schema/__tests__/create-key.js b/packages/gatsby/src/schema/__tests__/create-key.js
index eb4a28578422d..da6484dda1888 100644
--- a/packages/gatsby/src/schema/__tests__/create-key.js
+++ b/packages/gatsby/src/schema/__tests__/create-key.js
@@ -10,11 +10,17 @@ describe(`createKey`, () => {
   it(`replaces invalid characters`, () => {
     ;[
       [`/hello`, `_hello`],
-      [`~/path/to/some/module`, `_path_to_some_module`],
-      [`/*`, `_`],
-      [`/*.js`, `_js`],
+      [`~/path/to/some/module`, `_-path-to-some-module`],
+      [`/*`, `_-`],
+      [`/*.js`, `_--js`],
     ].forEach(([input, output]) => {
       expect(createKey(input)).toBe(output)
     })
   })
+
+  it(`does not generate same key for different input`, () => {
+    ;[[`/*.js`, `*js`]].forEach(([one, two]) => {
+      expect(createKey(one)).not.toBe(createKey(two))
+    })
+  })
 })
diff --git a/packages/gatsby/src/schema/create-key.js b/packages/gatsby/src/schema/create-key.js
index bc6b1bd3a57ca..4cb78499f5552 100644
--- a/packages/gatsby/src/schema/create-key.js
+++ b/packages/gatsby/src/schema/create-key.js
@@ -16,9 +16,9 @@ module.exports = (key: string): string => {
 
   const replaced = key.replace(nonAlphaNumericExpr, `_`)
 
-  // TODO: figure out what to replace this with _OR_ change the expr
+  // key is invalid; normalize with a leading underscore and dasherize rest
   if (replaced.match(/^__/)) {
-    return replaced.replace(/^_{2,}/, `_`)
+    return replaced.replace(/_/g, (char, index) => (index === 0 ? `_` : `-`))
   }
 
   return replaced