tests/test-phase-archived.t

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.

=========================================================
Test features and behaviors related to the archived phase
=========================================================

  $ cat << EOF >> $HGRCPATH
  > [format]
  > internal-phase=yes
  > [extensions]
  > strip=
  > [experimental]
  > EOF

  $ hg init repo
  $ cd repo
  $ echo  root > a
  $ hg add a
  $ hg ci -m 'root'

Test that bundle can unarchive a changeset
------------------------------------------

  $ echo foo >> a
  $ hg st
  M a
  $ hg ci -m 'unbundletesting'
  $ hg log -G
  @  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg strip --soft --rev '.'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/883aadbbf309-efc55adc-backup.hg
  $ hg log -G
  @  changeset:   0:c1863a3840c6
     tag:         tip
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg log -G --hidden
  o  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  @  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg unbundle .hg/strip-backup/883aadbbf309-efc55adc-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg log -G
  o  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  @  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  

Test that history rewriting command can use the archived phase when allowed to
------------------------------------------------------------------------------

  $ hg up 'desc(unbundletesting)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo bar >> a
  $ hg commit --amend --config experimental.cleanup-as-archived=yes
  $ hg log -G
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg log -G --hidden
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  | o  changeset:   1:883aadbbf309
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ ls -1 .hg/strip-backup/
  883aadbbf309-efc55adc-amend.hg
  883aadbbf309-efc55adc-backup.hg
  $ hg unbundle .hg/strip-backup/883aadbbf309*amend.hg
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg log -G
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  | o  changeset:   1:883aadbbf309
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root