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.
$ hg init
no bookmarks
$ hg bookmarks
no bookmarks set
set bookmark X
$ hg bookmark X
list bookmarks
$ hg bookmark
* X -1:000000000000
list bookmarks with color
$ hg --config extensions.color= --config color.mode=ansi \
> bookmark --color=always
\x1b[0;32m * \x1b[0m\x1b[0;32mX\x1b[0m\x1b[0;32m -1:000000000000\x1b[0m (esc)
update to bookmark X
$ hg bookmarks
* X -1:000000000000
$ hg update X
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
list bookmarks
$ hg bookmarks
* X -1:000000000000
rename
$ hg bookmark -m X Z
list bookmarks
$ cat .hg/bookmarks.current
Z (no-eol)
$ cat .hg/bookmarks
0000000000000000000000000000000000000000 Z
$ hg bookmarks
* Z -1:000000000000
new bookmarks X and Y, first one made active
$ hg bookmark Y X
list bookmarks
$ hg bookmark
X -1:000000000000
* Y -1:000000000000
Z -1:000000000000
$ hg bookmark -d X
commit
$ echo 'b' > b
$ hg add b
$ hg commit -m'test'
list bookmarks
$ hg bookmark
* Y 0:719295282060
Z -1:000000000000
Verify that switching to Z updates the active bookmark:
$ hg update Z
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
(activating bookmark Z)
$ hg bookmark
Y 0:719295282060
* Z -1:000000000000
Switch back to Y for the remaining tests in this file:
$ hg update Y
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark Y)
delete bookmarks
$ hg bookmark -d Y
$ hg bookmark -d Z
list bookmarks
$ hg bookmark
no bookmarks set
update to tip
$ hg update tip
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
set bookmark Y using -r . but make sure that the active
bookmark is not activated
$ hg bookmark -r . Y
list bookmarks, Y should not be active
$ hg bookmark
Y 0:719295282060
now, activate Y
$ hg up -q Y
set bookmark Z using -i
$ hg bookmark -r . -i Z
$ hg bookmarks
* Y 0:719295282060
Z 0:719295282060
deactivate active bookmark using -i
$ hg bookmark -i Y
$ hg bookmarks
Y 0:719295282060
Z 0:719295282060
$ hg up -q Y
$ hg bookmark -i
$ hg bookmarks
Y 0:719295282060
Z 0:719295282060
$ hg bookmark -i
no active bookmark
$ hg up -q Y
$ hg bookmarks
* Y 0:719295282060
Z 0:719295282060
deactivate active bookmark while renaming
$ hg bookmark -i -m Y X
$ hg bookmarks
X 0:719295282060
Z 0:719295282060
bare update moves the active bookmark forward and clear the divergent bookmarks
$ echo a > a
$ hg ci -Am1
adding a
$ echo b >> a
$ hg ci -Am2
$ hg bookmark X@1 -r 1
$ hg bookmark X@2 -r 2
$ hg update X
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
(activating bookmark X)
$ hg bookmarks
* X 0:719295282060
X@1 1:cc586d725fbe
X@2 2:49e1c4e84c58
Z 0:719295282060
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updating bookmark X
$ hg bookmarks
* X 2:49e1c4e84c58
Z 0:719295282060
test deleting .hg/bookmarks.current when explicitly updating
to a revision
$ echo a >> b
$ hg ci -m.
$ hg up -q X
$ test -f .hg/bookmarks.current
try to update to it again to make sure we don't
set and then unset it
$ hg up -q X
$ test -f .hg/bookmarks.current
$ hg up -q 1
$ test -f .hg/bookmarks.current
[1]
when a bookmark is active, hg up -r . is
analogous to hg book -i <active bookmark>
$ hg up -q X
$ hg up -q .
$ test -f .hg/bookmarks.current
[1]
issue 4552 -- simulate a pull moving the active bookmark
$ hg up -q X
$ printf "Z" > .hg/bookmarks.current
$ hg log -T '{activebookmark}\n' -r Z
Z
$ hg log -T '{bookmarks % "{active}\n"}' -r Z
Z
test that updating to closed branch head also advances active bookmark
$ hg commit --close-branch -m "closed"
$ hg update -q ".^1"
$ hg bookmark Y
$ hg bookmarks
X 3:4d6bd4bfb1ae
* Y 3:4d6bd4bfb1ae
Z 0:719295282060
$ hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
updating bookmark Y
$ hg bookmarks
X 3:4d6bd4bfb1ae
* Y 4:8fa964221e8e
Z 0:719295282060
$ hg parents -q
4:8fa964221e8e
Checks command to retrieve active bookmark
------------------------------------------
display how "{activebookmark}" template is unsuitable for the task
$ hg book -T '- {activebookmark}\n'
-
- Y
-
$ hg book -r . W
$ hg book -T '- {activebookmark}\n'
- Y
-
- Y
-
$ hg bookmarks -ql .
Y
$ hg bookmarks --inactive
$ hg bookmarks -ql .
abort: no active bookmark!
[255]