posix: always seek to EOF when opening a file in append mode
Python 3 already does this, so skip it there.
Consider the program:
#include <stdio.h>
int main() {
FILE *f = fopen("narf", "w");
fprintf(f, "narf\n");
fclose(f);
f = fopen("narf", "a");
printf("%ld\n", ftell(f));
fprintf(f, "troz\n");
printf("%ld\n", ftell(f));
return 0;
}
on macOS, FreeBSD, and Linux with glibc, this program prints
5
10
but on musl libc (Alpine Linux and probably others) this prints
0
10
By my reading of
https://pubs.opengroup.org/onlinepubs/009695399/functions/fopen.html
this is technically correct, specifically:
> Opening a file with append mode (a as the first character in the
> mode argument) shall cause all subsequent writes to the file to be
> forced to the then current end-of-file, regardless of intervening
> calls to fseek().
in other words, the file position doesn't really matter in append-mode
files, and we can't depend on it being at all meaningful unless we
perform a seek() before tell() after open(..., 'a'). Experimentally
after a .write() we can do a .tell() and it'll always be reasonable,
but I'm unclear from reading the specification if that's a smart thing
to rely on. This matches what we do on Windows and what Python 3 does
for free, so let's just be consistent. Thanks to Yuya for the idea.
============================================
Testing obsolescence markers push: Cases C.2
============================================
Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
all changesets that requested to be "in sync" after the push (even if they are
already on both side).
This test belongs to a series of tests checking such set is properly computed
and applied. This does not tests "obsmarkers" discovery capabilities.
Category C: advanced case
TestCase 2: Pruned changeset on precursors
Variants:
# a: explicite push
# b: bare push
C.2 Pruned changeset on precursors
==================================
.. {{{
.. B ⊗
.. |
.. A ø⇠◔ A'
.. |/
.. ● O
.. }}}
..
.. Marker exist from:
..
.. * A' succeed to A
.. * B (prune)
..
.. Command run:
..
.. * hg push -r A'
.. * hg push
..
.. Expected exchange:
..
.. * `A ø⇠o A'`
.. * B (prune)
Setup
-----
$ . $TESTDIR/testlib/exchange-obsmarker-util.sh
Itinial
$ setuprepos C.2
creating test repo for test case C.2
- pulldest
- main
- pushdest
cd into `main` and proceed with env setup
$ cd main
$ mkcommit A0
$ mkcommit B
$ hg prune -qd '0 0' .
$ hg update -q 0
$ mkcommit A1
created new head
$ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(A1)'`
obsoleted 1 changesets
$ hg log -G --hidden
@ e5ea8f9c7314 (draft): A1
|
| x 06055a7959d4 (draft): B
| |
| x 28b51eb45704 (draft): A0
|/
o a9bdc8b26820 (public): O
$ inspect_obsmarkers
obsstore content
================
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
$ cd ..
$ cd ..
$ cp -R C.2 C.2.a
$ cp -R C.2 C.2.b
Actual Test (explicit push)
---------------------------
$ dotest C.2.a A1
## Running testcase C.2.a
# testing echange of "A1" (e5ea8f9c7314)
## initial state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pushing "A1" from main to pushdest
pushing to pushdest
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
remote: 2 new obsolescence markers
## post push state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pulldest
## pulling "e5ea8f9c7314" from main into pulldest
pulling from main
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
2 new obsolescence markers
new changesets e5ea8f9c7314 (1 drafts)
(run 'hg update' to get a working copy)
## post pull state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pulldest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
Actual Test (bare push)
-------------------------------------
$ dotest C.2.b
## Running testcase C.2.b
## initial state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pushing from main to pushdest
pushing to pushdest
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
remote: 2 new obsolescence markers
## post push state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pulldest
## pulling from main into pulldest
pulling from main
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
2 new obsolescence markers
new changesets e5ea8f9c7314 (1 drafts)
(run 'hg update' to get a working copy)
## post pull state
# obstore: main
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pulldest
06055a7959d4128e6e3bccfd01482e83a2db8a3a 0 {28b51eb45704506b5c603decd6bf7ac5e0f6a52f} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}