tests/test-import-eol.t

localrepo: create new function for instantiating a local repo object

Today, there is a single local repository class - localrepository. Its
__init__ is responsible for loading the .hg/requires file and taking
different actions depending on what is present.

In addition, extensions may define a "reposetup" function that
monkeypatches constructed repository instances, often by implementing
a derived type and changing the __class__ of the repo instance.

Work around alternate storage backends and partial clone has made it
clear to me that shoehorning all this logic into __init__ and operating
on an existing instance is too convoluted. For example, localrepository
assumes revlog storage and swapping in non-revlog storage requires
overriding e.g. file() to return something that isn't a revlog. I've
authored various patches that either:

a) teach various methods (like file()) about different states and
   taking the appropriate code path at run-time
b) create methods/attributes/callables used for instantiating things
   and populating these in __init__

"a" incurs run-time performance penalties and makes code more
complicated since various functions have a bunch of "if storage is X"
branches.

"b" makes localrepository quickly explode in complexity.

My plan for tackling this problem is to make the local repository type
more dynamic. Instead of a static localrepository class/type that
supports all of the local repository configurations (revlogs vs other,
revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll
dynamically construct a type providing the implementations that are
needed for the repository on disk, derived from the .hg/requires file
and configuration options. The constructed repository type will be
specialized and methods won't need to be taught about different
implementations nor overloaded.

We may also leverage this functionality for building types that don't
implement all attributes. For example, the "intents" feature allows
commands to declare that they are read only. By dynamically
constructing a repository type, we could return a repository instance
with no attributes related to mutating the repository. This could
include things like a "changelog" property implementation that doesn't
check whether it needs to invalidate the hidden revisions set on every
access.

This commit establishes a function for building a local repository
instance. Future commits will start moving functionality from
localrepository.__init__ to this function. Then we'll start dynamically
changing the returned type depending on options that are present.

This change may seem radical. But it should be fully compatible with
the reposetup() model - at least for now.

Differential Revision: https://phab.mercurial-scm.org/D4563

  $ cat > makepatch.py <<EOF
  > import sys
  > f = open(sys.argv[2], 'wb')
  > w = f.write
  > w(b'test message\n')
  > w(b'diff --git a/a b/a\n')
  > w(b'--- a/a\n')
  > w(b'+++ b/a\n')
  > w(b'@@ -1,5 +1,5 @@\n')
  > w(b' a\n')
  > w(b'-bbb\r\n')
  > w(b'+yyyy\r\n')
  > w(b' cc\r\n')
  > w({'empty:lf': b' \n',
  >    'empty:crlf': b' \r\n',
  >    'empty:stripped-lf': b'\n',
  >    'empty:stripped-crlf': b'\r\n'}[sys.argv[1]])
  > w(b' d\n')
  > w(b'-e\n')
  > w(b'\ No newline at end of file\n')
  > w(b'+z\r\n')
  > w(b'\ No newline at end of file\r\n')
  > EOF

  $ hg init repo
  $ cd repo
  $ echo '\.diff' > .hgignore


Test different --eol values

  $ $PYTHON -c 'open("a", "wb").write(b"a\nbbb\ncc\n\nd\ne")'
  $ hg ci -Am adda
  adding .hgignore
  adding a
  $ $PYTHON ../makepatch.py empty:lf eol.diff
  $ $PYTHON ../makepatch.py empty:crlf eol-empty-crlf.diff
  $ $PYTHON ../makepatch.py empty:stripped-lf eol-empty-stripped-lf.diff
  $ $PYTHON ../makepatch.py empty:stripped-crlf eol-empty-stripped-crlf.diff

invalid eol

  $ hg --config patch.eol='LFCR' import eol.diff
  applying eol.diff
  abort: unsupported line endings type: LFCR
  [255]
  $ hg revert -a


force LF

  $ hg --traceback --config patch.eol='LF' import eol.diff
  applying eol.diff
  $ hg id
  9e4ef7b3d4af tip
  $ cat a
  a
  yyyy
  cc
  
  d
  e (no-eol)
  $ hg st

 (test empty-line variants: all of them should generate the same revision)

  $ hg up -qC 0
  $ hg --config patch.eol='LF' import eol-empty-crlf.diff
  applying eol-empty-crlf.diff
  $ hg id
  9e4ef7b3d4af tip

  $ hg up -qC 0
  $ hg --config patch.eol='LF' import eol-empty-stripped-lf.diff
  applying eol-empty-stripped-lf.diff
  $ hg id
  9e4ef7b3d4af tip

  $ hg up -qC 0
  $ hg --config patch.eol='LF' import eol-empty-stripped-crlf.diff
  applying eol-empty-stripped-crlf.diff
  $ hg id
  9e4ef7b3d4af tip

force CRLF

  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --traceback --config patch.eol='CRLF' import eol.diff
  applying eol.diff
  $ cat a
  a\r (esc)
  yyyy\r (esc)
  cc\r (esc)
  \r (esc)
  d\r (esc)
  e (no-eol)
  $ hg st


auto EOL on LF file

  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --traceback --config patch.eol='auto' import eol.diff
  applying eol.diff
  $ cat a
  a
  yyyy
  cc
  
  d
  e (no-eol)
  $ hg st


auto EOL on CRLF file

  $ $PYTHON -c 'open("a", "wb").write(b"a\r\nbbb\r\ncc\r\n\r\nd\r\ne")'
  $ hg commit -m 'switch EOLs in a'
  $ hg --traceback --config patch.eol='auto' import eol.diff
  applying eol.diff
  $ cat a
  a\r (esc)
  yyyy\r (esc)
  cc\r (esc)
  \r (esc)
  d\r (esc)
  e (no-eol)
  $ hg st


auto EOL on new file or source without any EOL

  $ $PYTHON -c 'open("noeol", "wb").write(b"noeol")'
  $ hg add noeol
  $ hg commit -m 'add noeol'
  $ $PYTHON -c 'open("noeol", "wb").write(b"noeol\r\nnoeol\n")'
  $ $PYTHON -c 'open("neweol", "wb").write(b"neweol\nneweol\r\n")'
  $ hg add neweol
  $ hg diff --git > noeol.diff
  $ hg revert --no-backup noeol neweol
  $ rm neweol
  $ hg --traceback --config patch.eol='auto' import -m noeol noeol.diff
  applying noeol.diff
  $ cat noeol
  noeol\r (esc)
  noeol
  $ cat neweol
  neweol
  neweol\r (esc)
  $ hg st


Test --eol and binary patches

  $ $PYTHON -c 'open("b", "wb").write(b"a\x00\nb\r\nd")'
  $ hg ci -Am addb
  adding b
  $ $PYTHON -c 'open("b", "wb").write(b"a\x00\nc\r\nd")'
  $ hg diff --git > bin.diff
  $ hg revert --no-backup b

binary patch with --eol

  $ hg import --config patch.eol='CRLF' -m changeb bin.diff
  applying bin.diff
  $ cat b
  a\x00 (esc)
  c\r (esc)
  d (no-eol)
  $ hg st
  $ cd ..