curenv doesn't work when embedded in C

[iacore]

Janet version: 1.30.0-bfb60fdb

When calling (make-image (curenv)) when embedded, the output buffer is wrong.

1. embedded in C

#include <janet.h>

int main(int argc, const char *argv[]) {
    // Initialize the virtual machine. Do this before any calls to Janet functions.
    janet_init();

    // Get the core janet environment. This contains all of the C functions in the core
    // as well as the code in src/boot/boot.janet.
    JanetTable *env = janet_core_env(NULL);

    // One of several ways to begin the Janet vm.
    janet_dostring(env, "(def abcdefg 1)  (pp (make-image (curenv)))", "main.janet", NULL);

    // Use this to free all resources allocated by Janet.
    janet_deinit();
    return 0;
}

Output: (The output is wrong)

❯ gcc test.c -ljanet && ./a.out
@"\xD8\broot-env"

2. script

this is correct

Output:

❯ cat /tmp/a.janet
(def abcdefg 1)  (pp (make-image (curenv)))
user@x17 ~/c/s/chargrid (main)
❯ janet /tmp/a.janet 
@"\xD4\x04\xD8\broot-env\xCF\aabcdefg\xD3\x02\xD0\nsource-map\xD2\x03\0\xCE\f/tmp/a.janet\x01\x01\xD0\x05value\x01\xD8\x06*args*\xD1\x01\xDA\x05\xD8\x0E*current-file*\xDA\x05\xD0\x06source\xDA\x05"

3. REPL

This is also correct.

❯ janet
Janet 1.30.0-bfb60fdb linux/x64/gcc - '(doc)' for help
repl:1:> (def abcdefg 1)  (pp (make-image (curenv)))
1
@"\xD4\x02\xD8\broot-env\xCF\x01_\xD3\x01\xD0\x05value\x01\xCF\aabcdefg\xD3\x02\xD0\nsource-map\xD2\x03\0\xCE\x04repl\x01\x01\xDA\x04\x01"
nil

[sogaiu]

In the embedded example, it looks like (curenv) and root-env evaluate to the same value. hash returns the same value for both and (= root-env (curenv)) returns true too.

IIUC, that may contribute to the if succeeding here (during marshalling):

https://github.com/janet-lang/janet/blob/a1b848ad76563ca2960507949a9b93a41735b697/src/core/marsh.c#L478-L485

...resulting in an early return and hence the buffer result of (make-image (curenv)) being @"\xD8\broot-env".

For the non-embedded cases, root-env and (curenv) evaluate to different tables and the if does not appear to succeed.

Within boot.janet / the janet executable, there often appears to be an environment constructed via make-env involved in evaluating code (whereas that doesn't appear to be occurring in the embedded case here). Perhaps this is part why the behaviors differ.

[iacore]

So the correct usage should be setting the prototype of a new table as core_env, and use that as environment?

[bakpakin]

You are running the environment table return from janet_core_env(), which is the root environment.

[iacore]

Should I update the first example here? Since running code directly in core_env is not the best practice.