MemorySanitizer complains about uninitialized (`---`) variables being passed to procedures, should it?

[joaocarvalhoopen]

Context

Operating System & Odin Version: Linux OpenSuse
My version of Odin is: odin version dev-2024-05:c091b0d06 Please paste odin report output:

 make run
./main.exe
==123765==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x4de60d in os.read_entire_file_from_handle /home/joaocarvalho/odin/Odin/core/os/os.odin:117:2
    #1 0x4dd943 in os.read_entire_file_from_filename /home/joaocarvalho/odin/Odin/core/os/os.odin:105:2
    #2 0x4d654a in main.main /home/joaocarvalho/odin_proj/tests/test_read_entire_file.odin:9:5
    #3 0x596df1 in main /home/joaocarvalho/odin/Odin/base/runtime/entry_unix.odin:54:4
    #4 0x7f54bc02a1ef in __libc_start_call_main (/lib64/libc.so.6+0x2a1ef) (BuildId: a2c0942c27fb9483b47886a1b937337a797bbceb)
    #5 0x7f54bc02a2b8 in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a2b8) (BuildId: a2c0942c27fb9483b47886a1b937337a797bbceb)
    #6 0x4360f4 in _start /home/abuild/rpmbuild/BUILD/glibc-2.39/csu/../sysdeps/x86_64/start.S:115

SUMMARY: MemorySanitizer: use-of-uninitialized-value /home/joaocarvalho/odin/Odin/core/os/os.odin:117:2 in os.read_entire_file_from_handle
Exiting
make: *** [Makefile:5: run] Error 1

Expected Behavior

Please describe the behavior you are expecting

Current Behavior

What is the current behavior?

If you run the following code compiled with

-sanitize:memory

package main

import "core:fmt"
import "core:os"

main :: proc ( ) {
    file_path := "test_read_entire_file.odin"

    data, sucess := os.read_entire_file_from_filename( file_path )
}

It will give the following warning:

==123765==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x4de60d in os.read_entire_file_from_handle /home/joaocarvalho/odin/Odin/core/os/os.odin:117:2
    #1 0x4dd943 in os.read_entire_file_from_filename /home/joaocarvalho/odin/Odin/core/os/os.odin:105:2
    #2 0x4d654a in main.main /home/joaocarvalho/odin_proj/tests/test_read_entire_file.odin:9:5

And looking at the code, we can see that this is a problem (length) inicialized outside the if with atribution:

read_entire_file_from_handle :: proc(fd: Handle, allocator := context.allocator, loc := #caller_location) -> (data: []byte, success: bool) {
   context.allocator = allocator

   length: i64
   err: Errno
   if length, err = file_size(fd); err != 0 {
       return nil, false
   }

   if length <= 0 {
      return nil, true
   }

It is saying that length scope is inside the if and that it is shadoing so the outside lenght is zero or unitialized.

Best regards, João Carvalho