tests/test-tools.t

revlog: seek to end of file before writing (issue4943)

Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.

Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.

The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.

Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.

This patch appears to have little to no impact on performance on my
Linux machine.

Tests of the file helper tool

  $ f -h
  ?sage: f [options] [filenames] (glob)
  
  ?ptions: (glob)
    -h, --help            show this help message and exit
    -t, --type            show file type (file or directory)
    -m, --mode            show file mode
    -l, --links           show number of links
    -s, --size            show size of file
    -n NEWER, --newer=NEWER
                          check if file is newer (or same)
    -r, --recurse         recurse into directories
    -S, --sha1            show sha1 hash of the content
    -M, --md5             show md5 hash of the content
    -D, --dump            dump file content
    -H, --hexdump         hexdump file content
    -B BYTES, --bytes=BYTES
                          number of characters to dump
    -L LINES, --lines=LINES
                          number of lines to dump
    -q, --quiet           no default output

  $ mkdir dir
  $ cd dir

  $ f --size
  size=0

  $ echo hello | f --md5 --size
  size=6, md5=b1946ac92492d2347c6235b4d2611184

  $ f foo
  foo: file not found

  $ echo foo > foo
  $ f foo
  foo:

#if symlink
  $ f foo --mode
  foo: mode=644
#endif

  $ python $TESTDIR/seq.py 10 > bar
#if unix-permissions symlink
  $ chmod +x bar
  $ f bar --newer foo --mode --type --size --dump --links --bytes 7
  bar: file, size=21, mode=755, links=1, newer than foo
  >>>
  1
  2
  3
  4
  <<< no trailing newline
#endif

#if unix-permissions
  $ ln bar baz
  $ f bar -n baz -l --hexdump -t --sha1 --lines=9 -B 20
  bar: file, links=2, newer than baz, sha1=612ca68d0305c821750a
  0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.|
  0010: 39 0a                                           |9.|
  $ rm baz
#endif

#if unix-permissions symlink
  $ ln -s yadda l
  $ f . --recurse -MStmsB4
  .: directory with 3 files, mode=755
  ./bar: file, size=21, mode=755, md5=3b03, sha1=612c
  ./foo: file, size=4, mode=644, md5=d3b0, sha1=f1d2
  ./l: link, size=5, md5=2faa, sha1=af93
#endif

  $ f --quiet bar -DL 3
  1
  2
  3

  $ cd ..

Yadda is a symlink
#if symlink
  $ f -qr dir -HB 17
  dir: directory with 3 files
  dir/bar:
  0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.|
  0010: 39                                              |9|
  dir/foo:
  0000: 66 6f 6f 0a                                     |foo.|
  dir/l:
  0000: 79 61 64 64 61                                  |yadda|
#else
  $ f -qr dir -HB 17
  dir: directory with 2 files (esc)
  dir/bar: (glob)
  0000: 31 0a 32 0a 33 0a 34 0a 35 0a 36 0a 37 0a 38 0a |1.2.3.4.5.6.7.8.|
  0010: 39                                              |9|
  dir/foo: (glob)
  0000: 66 6f 6f 0a                                     |foo.|
#endif