EJS Rethrow Function Memory Leak

[m-majetic]

I am testing this simple app on Ubuntu 18.04 with EJS version 2.6.1 and Express.js version 4.16.3 .

The home.ejs file is in a folder called home which is located in the views directory.
Contents of the .ejs files are the following:

I was investigating a memory leak in another app and decided to test it in the simplest manner possible.
Then, I made this app and the memory leak persists.
Testing for memory leakage was realized using node --inspect and expose GC flags.
User simulation was achieved using Siege.
The results:

Memory is constantly getting allocated to EJS strings, but the strings are never Garbage collected.

Am I missing something in my code, or is this ejs package related ?

[mde]

This looks like a much more helpful example than what we have previously gotten here: #359 (comment) It might help us narrow things further, although it could very well involve the way that EJS is integrated into Express. We don't see this issue with a minimal script that does nothing but require EJS, and render.

[m-majetic]

Interesting...
I will test this same simple app, but with older versions of express to see if we can pinpoint the update that caused this.
After that I think we should contact Express developers to see how is the ejs view engine treated and why are the references still present.

[m-majetic]

Hey, I suspect the problem is not EJS related. This is something on the express side.
I did the same experiment with pug...and would you know:

This is the server configuration and the pug file itself.

[m-majetic]

Looks like the problem was something under my nose the whole time...
Sorry to bother you.

expressjs/express#3751 (comment)