view tests/test-largefiles-small-disk.t @ 23845:0a7fd54d4e60

revset: introduce "_parsealiasdecl" to parse alias declarations strictly

This patch introduces "_parsealiasdecl" to parse alias declarations
strictly. For example, "_parsealiasdecl" can detect problems below,
which current implementation can't.

  - un-closed parenthesis causes being treated as "alias symbol"

    because all of declarations not in "func(....)" style are
    recognized as "alias symbol".

    for example, "foo($1, $2" is treated as the alias symbol.

  - alias symbol/function names aren't examined whether they are valid
    as symbol or not

    for example, "foo bar" can be treated as the alias symbol, but of
    course such invalid symbol can't be referred in revset.

  - just splitting argument list by "," causes overlooking syntax
    problems in the declaration

    for example, all of invalid declarations below are overlooked:

    - foo("bar")     => taking one argument named as '"bar"'
    - foo("unclosed) => taking one argument named as '"unclosed'
    - foo(bar::baz)  => taking one argument named as 'bar::baz'
    - foo(bar($1))   => taking one argument named as 'bar($1)'

To decrease complication of patch, current implementation for alias
declarations is replaced by "_parsealiasdecl" in the subsequent
patch. This patch just introduces it.

This patch defines "_parsealiasdecl" not as a method of "revsetalias"
class but as a one of "revset" module, because of ease of testing by
doctest.

This patch factors some helper functions for "tree" out, because:

  - direct accessing like "if tree[0] == 'func' and len(tree) > 1"
    decreases readability

  - subsequent patch (and also existing code paths, in the future) can
    use them for readability

This patch also factors "_tokenizealias" out, because it can be used
also for parsing alias definitions strictly.

Test how largefiles abort in case the disk runs full

  $ cat > criple.py <<EOF
  > import os, errno, shutil
  > from mercurial import util
  > #
  > # this makes the original largefiles code abort:
  > def copyfileobj(fsrc, fdst, length=16*1024):
  >     fdst.write(fsrc.read(4))
  >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
  > shutil.copyfileobj = copyfileobj
  > #
  > # this makes the rewritten code abort:
  > def filechunkiter(f, size=65536, limit=None):
  >     yield f.read(4)
  >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
  > util.filechunkiter = filechunkiter
  > #
  > def oslink(src, dest):
  >     raise OSError("no hardlinks, try copying instead")
  > util.oslink = oslink
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "largefiles =" >> $HGRCPATH

  $ hg init alice
  $ cd alice
  $ echo "this is a very big file" > big
  $ hg add --large big
  $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big
  abort: No space left on device
  [255]

The largefile is not created in .hg/largefiles:

  $ ls .hg/largefiles
  dirstate

The user cache is not even created:

  >>> import os; os.path.exists("$HOME/.cache/largefiles/")
  False

Make the commit with space on the device:

  $ hg commit -m big

Now make a clone with a full disk, and make sure lfutil.link function
makes copies instead of hardlinks:

  $ cd ..
  $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  getting changed largefiles
  abort: No space left on device
  [255]

The largefile is not created in .hg/largefiles:

  $ ls bob/.hg/largefiles
  dirstate