ref(gatsby): Default release to empty string (getsentry#3759)

To make gatsby work better out of the box, we set the default
for the release value to be undefined instead of an empty string.

Author: AbhiPrasad

packages/gatsby/gatsby-node.js

@@ -11,7 +11,7 @@ const sentryRelease = JSON.stringify(
     process.env.ZEIT_GITHUB_COMMIT_SHA ||
     process.env.ZEIT_GITLAB_COMMIT_SHA ||
     process.env.ZEIT_BITBUCKET_COMMIT_SHA ||
-    '',
+    undefined,
 );
 
 const sentryDsn = JSON.stringify(process.env.SENTRY_DSN || '');

packages/gatsby/package.json

@@ -86,7 +86,10 @@
         "tsConfig": "./tsconfig.json",
         "diagnostics": false
       }
-    }
+    },
+    "setupFiles": [
+      "<rootDir>/test/setEnvVars.ts"
+    ]
   },
   "sideEffects": false
 }

packages/gatsby/test/gatsby-node.test.ts

@@ -1,6 +1,5 @@
 /* eslint-disable @typescript-eslint/no-var-requires */
 /* eslint-disable @typescript-eslint/no-explicit-any */
-
 const { onCreateWebpackConfig } = require('../gatsby-node');
 
 describe('onCreateWebpackConfig', () => {

packages/gatsby/test/setEnvVars.ts

@@ -0,0 +1,2 @@
+// eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-member-access
+process.env.SENTRY_RELEASE = '14abbb1678a2eb59d1a171ea33d630dd6c6eee70';