[PATCH V3] update: fix edge-case with update.atomic-file and read-only files
Boris Feld
boris.feld at octobus.net
Mon Jan 14 09:04:30 UTC 2019
# HG changeset patch
# User Boris Feld <boris.feld at octobus.net>
# Date 1547128621 -3600
# Thu Jan 10 14:57:01 2019 +0100
# Node ID 0a3fe47decbe8920754e44d6448bfa474990edd3
# Parent 963462786f6e028563bcedc9008622e0f3b59c86
# EXP-Topic atomic-update-read-only
# Available At https://bitbucket.org/octobus/mercurial-devel/
# hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 0a3fe47decbe
update: fix edge-case with update.atomic-file and read-only files
We used to create the tempfile with the original file mode. That means
creating a read-only tempfile when the original file is read-only, which crash
if we need to write on the tempfile.
The file in the working directory ends up being writable with and without the
atomic update config, so the behavior is the same.
diff --git a/mercurial/posix.py b/mercurial/posix.py
--- a/mercurial/posix.py
+++ b/mercurial/posix.py
@@ -153,7 +153,7 @@ def setflags(f, l, x):
# Turn off all +x bits
os.chmod(f, s & 0o666)
-def copymode(src, dst, mode=None):
+def copymode(src, dst, mode=None, enforcewritable=False):
'''Copy the file mode from the file at path src to dst.
If src doesn't exist, we're using mode instead. If mode is None, we're
using umask.'''
@@ -166,7 +166,13 @@ def copymode(src, dst, mode=None):
if st_mode is None:
st_mode = ~umask
st_mode &= 0o666
- os.chmod(dst, st_mode)
+
+ new_mode = st_mode
+
+ if enforcewritable:
+ new_mode |= stat.S_IWUSR
+
+ os.chmod(dst, new_mode)
def checkexec(path):
"""
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -2045,7 +2045,7 @@ def splitpath(path):
function if need.'''
return path.split(pycompat.ossep)
-def mktempcopy(name, emptyok=False, createmode=None):
+def mktempcopy(name, emptyok=False, createmode=None, enforcewritable=False):
"""Create a temporary file with the same contents from name
The permission bits are copied from the original file.
@@ -2061,7 +2061,8 @@ def mktempcopy(name, emptyok=False, crea
# Temporary files are created with mode 0600, which is usually not
# what we want. If the original file already exists, just copy
# its mode. Otherwise, manually obey umask.
- copymode(name, temp, createmode)
+ copymode(name, temp, createmode, enforcewritable)
+
if emptyok:
return temp
try:
@@ -2204,7 +2205,9 @@ class atomictempfile(object):
def __init__(self, name, mode='w+b', createmode=None, checkambig=False):
self.__name = name # permanent name
self._tempname = mktempcopy(name, emptyok=('w' in mode),
- createmode=createmode)
+ createmode=createmode,
+ enforcewritable=('w' in mode))
+
self._fp = posixfile(self._tempname, mode)
self._checkambig = checkambig
diff --git a/tests/test-update-atomic.t b/tests/test-update-atomic.t
new file mode 100644
--- /dev/null
+++ b/tests/test-update-atomic.t
@@ -0,0 +1,142 @@
+#require execbit
+
+Checking that experimental.atomic-file works.
+
+ $ cat > $TESTTMP/show_mode.py <<EOF
+ > from __future__ import print_function
+ > import sys
+ > import os
+ > from stat import ST_MODE
+ >
+ > for file_path in sys.argv[1:]:
+ > file_stat = os.stat(file_path)
+ > octal_mode = oct(file_stat[ST_MODE] & 0o777)
+ > print("%s:%s" % (file_path, octal_mode))
+ >
+ > EOF
+
+ $ hg init repo
+ $ cd repo
+
+ $ cat > .hg/showwrites.py <<EOF
+ > def uisetup(ui):
+ > from mercurial import vfs
+ > class newvfs(vfs.vfs):
+ > def __call__(self, *args, **kwargs):
+ > print('vfs open', args, sorted(list(kwargs.items())))
+ > return super(newvfs, self).__call__(*args, **kwargs)
+ > vfs.vfs = newvfs
+ > EOF
+
+ $ for v in a1 a2 b1 b2 c ro; do echo $v > $v; done
+ $ chmod +x b*
+ $ hg commit -Aqm _
+
+# We check that
+# - the changes are actually atomic
+# - that permissions are correct (all 4 cases of (executable before) * (executable after))
+# - that renames work, though they should be atomic anyway
+# - that it works when source files are read-only (but directories are read-write still)
+
+ $ for v in a1 a2 b1 b2 ro; do echo changed-$v > $v; done
+ $ chmod -x *1; chmod +x *2
+ $ hg rename c d
+ $ hg commit -qm _
+
+Check behavior without update.atomic-file
+
+ $ hg update -r 0 -q
+ $ hg update -r 1 --config extensions.showwrites=.hg/showwrites.py 2>&1 | grep "a1'.*wb"
+ ('vfs open', ('a1', 'wb'), [('atomictemp', False), ('backgroundclose', True)])
+
+ $ python $TESTTMP/show_mode.py *
+ a1:0644
+ a2:0755
+ b1:0644
+ b2:0755
+ d:0644
+ ro:0644
+
+Add a second revision for the ro file so we can test update when the file is
+present or not
+
+ $ echo "ro" > ro
+
+ $ hg commit -qm _
+
+Check behavior without update.atomic-file first
+
+ $ hg update -C -r 0 -q
+
+ $ hg update -r 1
+ 6 files updated, 0 files merged, 1 files removed, 0 files unresolved
+
+ $ python $TESTTMP/show_mode.py *
+ a1:0644
+ a2:0755
+ b1:0644
+ b2:0755
+ d:0644
+ ro:0644
+
+Manually reset the mode of the read-only file
+
+ $ chmod a-w ro
+
+ $ python $TESTTMP/show_mode.py ro
+ ro:0444
+
+Now the file is present, try to update and check the permissions of the file
+
+ $ hg up -r 2
+ 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+ $ python $TESTTMP/show_mode.py ro
+ ro:0644
+
+# The file which was read-only is now writable in the default behavior
+
+Check behavior with update.atomic-files
+
+
+ $ cat >> .hg/hgrc <<EOF
+ > [experimental]
+ > update.atomic-file = true
+ > EOF
+
+ $ hg update -C -r 0 -q
+ $ hg update -r 1 --config extensions.showwrites=.hg/showwrites.py 2>&1 | grep "a1'.*wb"
+ ('vfs open', ('a1', 'wb'), [('atomictemp', True), ('backgroundclose', True)])
+ $ hg st -A --rev 1
+ C a1
+ C a2
+ C b1
+ C b2
+ C d
+ C ro
+
+Check the file permission after update
+ $ python $TESTTMP/show_mode.py *
+ a1:0644
+ a2:0755
+ b1:0644
+ b2:0755
+ d:0644
+ ro:0644
+
+Manually reset the mode of the read-only file
+
+ $ chmod a-w ro
+
+ $ python $TESTTMP/show_mode.py ro
+ ro:0444
+
+Now the file is present, try to update and check the permissions of the file
+
+ $ hg update -r 2 --traceback
+ 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+ $ python $TESTTMP/show_mode.py ro
+ ro:0644
+
+# The behavior is the same as without atomic update
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