Save does not return an error when the file does not exist

[roidelapluie]

in roidelapluie/go-augtest@dca84f5

the file /tmp/foo/bar does not exist, is not created, but still augeas.Save() does not return an error.

[hillu]

Just tried to reproduce the error. Apparently, the directory must exist. Tried the following in an empty directory (augeas 1.8, Debian/stretch chroot):

$ augtool --root .
augtool> set /augeas/load/Xmgmt/lens Sshd.lns
augtool> set /augeas/load/Xmgmt/incl /tmp/foo/bar
augtool> set /files/tmp/foo/bar/X11Forwarding no
augtool> save
error: Failed to execute command
saving failed (run 'errors' for details)
augtool> errors
Error in /tmp/foo/bar (mk_augtemp)
  No such file or directory

I can confirm that your test program produces no error -- this is a bug in the library, indeed.

After creating the directory and repeating the procedure everything works fine from augtool.

[hillu]

Digging further... a simple C test program to reproduce this issue behaves correctly in the sense that -1 is returned.

#include <stdio.h>
#include <augeas.h>
#include <assert.h>

int main(int argc, char** argv) {
  augeas *a;
  int r;
  a = aug_init("./", "", 0);
  assert(a != NULL);
  r = aug_load(a);
  r = aug_set(a, "/augeas/load/Xmgmt/lens", "Sshd.lns");
  assert(r!=-1);
  r = aug_set(a, "/augeas/load/Xmgmt/incl", "/tmp/foo/bar");
  assert(r!=-1);
  r = aug_set(a, "/files/tmp/foo/bar/X11Forwarding", "no");
  assert(r!=-1);
  r = aug_save(a);
  printf("aug_save: %d\n", r);
  printf("code: %d, msg: %s, minormsg: %s, details: %s\n",
	 aug_error(a),
	 aug_error_message(a),
	 aug_error_minor_message(a),
	 aug_error_details(a));
  assert(r==0);
}

However, the aug_error_* functions return nothing sensible:

aug_save: -1
code: 0, msg: No error, minormsg: (null), details: (null)
13t: 13t.c:24: main: Assertion `r==0' failed.
Aborted

augtool tells us to get the errors through a dedicated command which prints out the messages from the /augeas//error tree... go-augeas should probably return a generic error in this case.