Cloud Functions: Incorrect/incomplete transformation of escape sequences in .env files

[yellcorp]

[REQUIRED] Environment info

firebase-tools: 10.2.2

Platform: macOS (11.6.2 Big Sur)

[REQUIRED] Test case

1. Create a new Node project

   mkdir firebasetoolstest
   cd firebasetoolstest
   npm init # (accept default answers)

2. Add this package as a devDependency

   npm i -DE firebase-tools@10.2.2

3. Init a new Firebase project

   npx firebase init
   # Which Firebase features: enable 'Functions'
   # Project setup: Create a new project
   # Please specify a unique project id: (your choice)
   # What would you like to call your project: (your choice)
   # What language would you like to use to write Cloud Functions?: JavaScript
   # Do you want to use ESLint to catch probable bugs and enforce style? N
   # Do you want to install dependencies with npm now? Y

4. Edit functions/index.js to have the following content:

   const functions = require("firebase-functions");
   
   exports.envParseTest = functions.https.onRequest((request, response) => {
     const text = process.env.ENVTEST_SAMPLE;
     const lines = text.split("\n");
     const lineCount = lines.length;
     const bytes = Array.from(Buffer.from(text));
     response.json({ text, lines, lineCount, bytes });
   });

5. Create functions/.env with the following content:

   ENVTEST_SAMPLE="foo\nbar\nbaz"

6. At this point it's sufficient to run the Cloud Functions emulator to reproduce the issue.

   npx firebase emulators:start --only functions

[REQUIRED] Steps to reproduce

Open the indicated URL for the envParseTest function in a browser, or some terminal-based HTTP client.

curl 'http://localhost:5001/$GCLOUD_PROJECT/us-central1/envParseTest'

[REQUIRED] Expected behavior

A response with the content

{"text":"foo\nbar\nbaz","lines":["foo","bar","baz"],"lineCount":3,"bytes":[102,111,111,10,98,97,114,10,98,97,122]}

[REQUIRED] Actual behavior

A response with the content

{"text":"foo\nbar\\nbaz","lines":["foo","bar\\nbaz"],"lineCount":2,"bytes":[102,111,111,10,98,97,114,92,110,98,97,122]}

Note in the "text" property - the first \n from the .env has been correctly interpreted as a newline; the second remains as a literal \ followed by a literal n. This test also outputs a bytes property to show the parse result unambiguously. A newline appears in the array as decimal 10, a literal \ followed by literal n appears as decimal 92,110.

Debug log from firebase emulators:start is attached.
firebase-debug.log

[taeold]

@yellcorp Thank you again for your wonderful contribution.