[TS] flatc flags `--ts-flat-files` and `--ts-entry-points` have no effect

[yblein]

Using --ts-flat-files makes flatc output those 3 lines:

> ./flatc -o /tmp/fb --ts samples/monster.fbs --ts-flat-files
Entry point /tmp/fb/monster.ts generated.
A single file bundle can be created using fx. esbuild with:
> esbuild /tmp/fb/monster.ts --format=cjs --bundle --outfile=/tmp/fb/monster_generated.js --external:flatbuffers

However, despite it claiming to have generated /tmp/fb/monster.ts, no such file exists.
Additionally, it still generated the exact same files as without any flags:

> tree /tmp/fb/my-game
/tmp/fb/my-game
├── sample
│   ├── color.ts
│   ├── equipment.ts
│   ├── monster.ts
│   ├── vec3.ts
│   └── weapon.ts
└── sample.ts

A quick look into src/idl_gen_ts.cpp shows that the field IDLOptions::ts_flat_files is indeed only used to decide whether to print the above message or not, and has not effect whatsoever on code generation.

Additionally, I was also surprised to see that IDLOptions::ts_entry_points is never read, and has no effect on code generation either. I looked into it since it is implied by --ts-flat-files (per flatc --help).

This was run from a fresh build on linux:

> git describe --always --dirty
v25.2.10-52-g48eccb83
> g++ -dumpmachine
x86_64-pc-linux-gnu

[jtdavis777]

@bjornharrtell any thoughts here?

[bjornharrtell]

@jtdavis777 honestly I don't see the point of --ts-flat-files. It seem it was introduced to make bazel happy as the only argument in #7161 and that doesn't make sense to me.

It's probably right that --ts-entry-points cannot be set to false. I also feel this is the only sensible way to generate the code.

I would remove both options since they make no sense to me. :)

Mabye @jkuszmaul or @dbaileychess can provide some input?

[jtdavis777]

I think for the sake of continuity it may make sense to still accept these options but mark them as deprecated, no effect and remove all functionality from flatc. It looks like all actual implementation code from #7161 has been removed as part of your PR #7510 -- I am not sure if the functionality Entry point /tmp/fb/monster.ts generated. did ever exist? Maybe this is just supposed to reference sample/monster.ts? Not my area of expertise :)

I'd be happy to write the deprecation PR if you can help me understand what documentation updates might be warranted to capture the esbuild comments.

[jkuszmaul]

Yeah, it's not doing anything useful right now. For our Bazel usage, we just had to move to forcing people to manually specify what types are present in the .fbs files so that Bazel knows what files to expect. I really dislike doing so, but we haven't been using flatbuffers typescript codegen quite enough to need to find a better solution.