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.
#testcases flat tree
$ . "$TESTDIR/narrow-library.sh"
#if tree
$ cat << EOF >> $HGRCPATH
> [experimental]
> treemanifest = 1
> EOF
#endif
$ cat << EOF >> $HGRCPATH
> [extensions]
> share =
> EOF
$ hg init remote
$ cd remote
$ for x in `$TESTDIR/seq.py 0 10`
> do
> mkdir d$x
> echo $x > d$x/f
> hg add d$x/f
> hg commit -m "add d$x/f"
> done
$ cd ..
$ hg clone --narrow ssh://user@dummy/remote main -q \
> --include d1 --include d3 --include d5 --include d7
$ hg share main share
updating working directory
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R share tracked
I path:d1
I path:d3
I path:d5
I path:d7
$ hg -R share files
share/d1/f
share/d3/f
share/d5/f
share/d7/f
Narrow the share and check that the main repo's working copy gets updated
# Make sure the files that are supposed to be known-clean get their timestamps set in the dirstate
$ sleep 2
$ hg -R main st
$ hg -R main debugdirstate --no-dates
n 644 2 set d1/f
n 644 2 set d3/f
n 644 2 set d5/f
n 644 2 set d7/f
# Make d3/f dirty
$ echo x >> main/d3/f
$ echo y >> main/d3/g
$ hg add main/d3/g
$ hg -R main st
M d3/f
A d3/g
# Make d5/f not match the dirstate timestamp even though it's clean
$ sleep 2
$ hg -R main st
M d3/f
A d3/g
$ hg -R main debugdirstate --no-dates
n 644 2 set d1/f
n 644 2 set d3/f
a 0 -1 unset d3/g
n 644 2 set d5/f
n 644 2 set d7/f
$ touch main/d5/f
$ hg -R share tracked --removeinclude d1 --removeinclude d3 --removeinclude d5
comparing with ssh://user@dummy/remote
searching for changes
looking for local changes to affected paths
deleting data/d1/f.i
deleting data/d3/f.i
deleting data/d5/f.i
deleting meta/d1/00manifest.i (tree !)
deleting meta/d3/00manifest.i (tree !)
deleting meta/d5/00manifest.i (tree !)
$ hg -R main tracked
I path:d7
$ hg -R main files
abort: working copy's narrowspec is stale
(run 'hg tracked --update-working-copy')
[255]
$ hg -R main tracked --update-working-copy
not deleting possibly dirty file d3/f
not deleting possibly dirty file d3/g
not deleting possibly dirty file d5/f
# d1/f, d3/f, d3/g and d5/f should no longer be reported
$ hg -R main files
main/d7/f
# d1/f should no longer be there, d3/f should be since it was dirty, d3/g should be there since
# it was added, and d5/f should be since we couldn't be sure it was clean
$ find main/d* -type f | sort
main/d3/f
main/d3/g
main/d5/f
main/d7/f
Widen the share and check that the main repo's working copy gets updated
$ hg -R share tracked --addinclude d1 --addinclude d3 -q
$ hg -R share tracked
I path:d1
I path:d3
I path:d7
$ hg -R share files
share/d1/f
share/d3/f
share/d7/f
$ hg -R main tracked
I path:d1
I path:d3
I path:d7
$ hg -R main files
abort: working copy's narrowspec is stale
(run 'hg tracked --update-working-copy')
[255]
$ hg -R main tracked --update-working-copy
# d1/f, d3/f should be back
$ hg -R main files
main/d1/f
main/d3/f
main/d7/f
# d3/f should be modified (not clobbered by the widening), and d3/g should be untracked
$ hg -R main st --all
M d3/f
? d3/g
C d1/f
C d7/f
We should also be able to unshare without breaking everything:
$ hg share main share-unshare
updating working directory
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd share-unshare
$ hg unshare
$ hg verify
checking changesets
checking manifests
checking directory manifests (tree !)
crosschecking files in changesets and manifests
checking files
checked 11 changesets with 3 changes to 3 files
$ cd ..
Dirstate should be left alone when upgrading from version of hg that didn't support narrow+share
$ hg share main share-upgrade
updating working directory
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd share-upgrade
$ echo x >> d1/f
$ echo y >> d3/g
$ hg add d3/g
$ hg rm d7/f
$ hg st
M d1/f
A d3/g
R d7/f
Make it look like a repo from before narrow+share was supported
$ rm .hg/narrowspec.dirstate
$ hg ci -Am test
abort: working copy's narrowspec is stale
(run 'hg tracked --update-working-copy')
[255]
$ hg tracked --update-working-copy
$ hg st
M d1/f
A d3/g
R d7/f
$ cd ..