##// END OF EJS Templates
posix: always seek to EOF when opening a file in append mode...
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.

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generate-working-copy-states.py
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/ tests / generate-working-copy-states.py
# Helper script used for generating history and working copy files and content.
# The file's name corresponds to its history. The number of changesets can
# be specified on the command line. With 2 changesets, files with names like
# content1_content2_content1-untracked are generated. The first two filename
# segments describe the contents in the two changesets. The third segment
# ("content1-untracked") describes the state in the working copy, i.e.
# the file has content "content1" and is untracked (since it was previously
# tracked, it has been forgotten).
#
# This script generates the filenames and their content, but it's up to the
# caller to tell hg about the state.
#
# There are two subcommands:
# filelist <numchangesets>
# state <numchangesets> (<changeset>|wc)
#
# Typical usage:
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 1
# $ hg addremove --similarity 0
# $ hg commit -m 'first'
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 1
# $ hg addremove --similarity 0
# $ hg commit -m 'second'
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 wc
# $ hg addremove --similarity 0
# $ hg forget *_*_*-untracked
# $ rm *_*_missing-*
from __future__ import absolute_import, print_function
import os
import sys
# Generates pairs of (filename, contents), where 'contents' is a list
# describing the file's content at each revision (or in the working copy).
# At each revision, it is either None or the file's actual content. When not
# None, it may be either new content or the same content as an earlier
# revisions, so all of (modified,clean,added,removed) can be tested.
def generatestates(maxchangesets, parentcontents):
depth = len(parentcontents)
if depth == maxchangesets + 1:
for tracked in (b'untracked', b'tracked'):
filename = b"_".join([(content is None and b'missing' or content)
for content in parentcontents]) + b"-" + tracked
yield (filename, parentcontents)
else:
for content in ({None, b'content' + (b"%d" % (depth + 1))} |
set(parentcontents)):
for combination in generatestates(maxchangesets,
parentcontents + [content]):
yield combination
# retrieve the command line arguments
target = sys.argv[1]
maxchangesets = int(sys.argv[2])
if target == 'state':
depth = sys.argv[3]
# sort to make sure we have stable output
combinations = sorted(generatestates(maxchangesets, []))
# compute file content
content = []
for filename, states in combinations:
if target == 'filelist':
print(filename.decode('ascii'))
elif target == 'state':
if depth == 'wc':
# Make sure there is content so the file gets written and can be
# tracked. It will be deleted outside of this script.
content.append((filename, states[maxchangesets] or b'TOBEDELETED'))
else:
content.append((filename, states[int(depth) - 1]))
else:
print("unknown target:", target, file=sys.stderr)
sys.exit(1)
# write actual content
for filename, data in content:
if data is not None:
f = open(filename, 'wb')
f.write(data + b'\n')
f.close()
elif os.path.exists(filename):
os.remove(filename)