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.
Tests for the automv extension; detect moved files at commit time.
$ cat >> $HGRCPATH << EOF
> [extensions]
> automv=
> rebase=
> EOF
Setup repo
$ hg init repo
$ cd repo
Test automv command for commit
$ printf 'foo\nbar\nbaz\n' > a.txt
$ hg add a.txt
$ hg commit -m 'init repo with a'
mv/rm/add
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit -m 'msg'
detected move of 1 files
$ hg status --change . -C
A b.txt
a.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
mv/rm/add/modif
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit -m 'msg'
detected move of 1 files
created new head
$ hg status --change . -C
A b.txt
a.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
mv/rm/add/modif
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\nfoo\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit -m 'msg'
created new head
$ hg status --change . -C
A b.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
mv/rm/add/modif/changethreshold
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\nfoo\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --config automv.similarity='60' -m 'msg'
detected move of 1 files
created new head
$ hg status --change . -C
A b.txt
a.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
mv
$ mv a.txt b.txt
$ hg status -C
! a.txt
? b.txt
$ hg commit -m 'msg'
nothing changed (1 missing files, see 'hg status')
[1]
$ hg status -C
! a.txt
? b.txt
$ hg revert -aqC
$ rm b.txt
mv/rm/add/notincommitfiles
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ echo 'bar' > c.txt
$ hg add c.txt
$ hg status -C
A b.txt
A c.txt
R a.txt
$ hg commit c.txt -m 'msg'
created new head
$ hg status --change . -C
A c.txt
$ hg status -C
A b.txt
R a.txt
$ hg up -r 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg rm a.txt
$ echo 'bar' > c.txt
$ hg add c.txt
$ hg commit -m 'msg'
detected move of 1 files
created new head
$ hg status --change . -C
A b.txt
a.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv/rm/add/--no-automv
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --no-automv -m 'msg'
created new head
$ hg status --change . -C
A b.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
Test automv command for commit --amend
mv/rm/add
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend -m 'amended'
detected move of 1 files
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
a.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv/rm/add/modif
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend -m 'amended'
detected move of 1 files
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
a.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv/rm/add/modif
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\nfoo\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend -m 'amended'
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv/rm/add/modif/changethreshold
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ printf '\nfoo\n' >> b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend --config automv.similarity='60' -m 'amended'
detected move of 1 files
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
a.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg status -C
! a.txt
? b.txt
$ hg commit --amend -m 'amended'
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status -C
! a.txt
? b.txt
$ hg up -Cr 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
mv/rm/add/notincommitfiles
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ echo 'bar' > d.txt
$ hg add d.txt
$ hg status -C
A b.txt
A d.txt
R a.txt
$ hg commit --amend -m 'amended' d.txt
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A c.txt
A d.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend -m 'amended'
detected move of 1 files
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
a.txt
A c.txt
A d.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 3 files removed, 0 files unresolved
mv/rm/add/--no-automv
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg add b.txt
$ hg status -C
A b.txt
R a.txt
$ hg commit --amend -m 'amended' --no-automv
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
A c.txt
R a.txt
$ hg up -r 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
mv/rm/commit/add/amend
$ echo 'c' > c.txt
$ hg add c.txt
$ hg commit -m 'revision to amend to'
created new head
$ mv a.txt b.txt
$ hg rm a.txt
$ hg status -C
R a.txt
? b.txt
$ hg commit -m "removed a"
$ hg add b.txt
$ hg commit --amend -m 'amended'
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-amend.hg (glob)
$ hg status --change . -C
A b.txt
R a.txt
error conditions
$ cat >> $HGRCPATH << EOF
> [automv]
> similarity=110
> EOF
$ hg commit -m 'revision to amend to'
abort: automv.similarity must be between 0 and 100
[255]