Preserve executable file permission when generating from executable .ts file

As many libraries ship executable files to help with testing or administration it is convenient to be able to keep the executable permission on UNIX like systems while generating .js files from .ts files. The creator of the library can provide a build script or manually keep the proper permissions in distributed generated library but this is sub-optimal

TypeScript Version: 2.9.2 Search Terms: file permissions executable

Expected behavior:

$ ll lib/jem_cli.ts 
-rwxr-xr-x 1 omg omg 5.9K 30 Jul 12,58 lib/jem_cli.ts
$ tsc 
TSFILE: ..../jem_cli.js
$ ll jem_cli.js 
-rwxr-xr-x 1 omg omg 8.2K 30 Jul 13,23 jem_cli.js

Actual behavior:

$ ll lib/jem_cli.ts 
-rwxr-xr-x 1 omg omg 5.9K 30 Jul 12,58 lib/jem_cli.ts
$ tsc 
TSFILE: ..../jem_cli.js
$ ll jem_cli.js 
-rw-r--r-- 1 omg omg 8.2K 30 Jul 13,23 jem_cli.js

[jcollum]

I agree with @sdrsdr: changing the flags on emitted files is a violation of POLA: I would not expect the flags to be changed after compilation.

This is what I get after running tsc and sending output to dist folder:

$ ll src
total 4
-rw-r--r--  1 justin.collum  NWEA\Domain Users   2.1K Oct  8 11:13 index.ts
$ ll dist
total 11552
-rw-------   1 justin.collum  NWEA\Domain Users   3.5K Oct  8 11:13 index.js
drwxr-xr-x  32 justin.collum  NWEA\Domain Users   1.0K Oct  8 11:13 node_modules/

Definitely not what I expected. tsc seems to be emitting a file with the least amount of permissions. I’m uploading this file to Lambda and the Lambda executor can’t access the code:

"EACCES: permission denied, open '/var/task/index.js'",

I can workaround this. However it is a violation of POLA in my opinion.

[sdrsdr]

This is a bit more complicated: A single compilation host is used for complete compilation task. You can track all source and output files, but there is no one to one relation. You can make a map out of input files and their permissions and match in it the output filenames and act accordingly. This might lead to some performance degradation in huge projects, so I was thinking about adding an compiler option to enable this behavior and keeping it off by default. Also to keep the map small I’m thinking about “remembering” only the executable input files. This will bring the lookup time to almost zero, yet you have to lookup file permissions for every input file.