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.
test command parsing and dispatch
$ hg init a
$ cd a
Redundant options used to crash (issue436):
$ hg -v log -v
$ hg -v log -v x
$ echo a > a
$ hg ci -Ama
adding a
Missing arg:
$ hg cat
hg cat: invalid arguments
hg cat [OPTION]... FILE...
output the current or given revision of files
options ([+] can be repeated):
-o --output FORMAT print output to file with formatted name
-r --rev REV print the given revision
--decode apply any matching decode filter
-I --include PATTERN [+] include names matching the given patterns
-X --exclude PATTERN [+] exclude names matching the given patterns
-T --template TEMPLATE display with template
(use 'hg cat -h' to show more help)
[255]
Missing parameter for early option:
$ hg log -R 2>&1 | grep 'hg log'
hg log: option -R requires argument
hg log [OPTION]... [FILE]
(use 'hg log -h' to show more help)
"--" may be an option value:
$ hg -R -- log
abort: repository -- not found!
[255]
$ hg log -R --
abort: repository -- not found!
[255]
$ hg log -T --
-- (no-eol)
$ hg log -T -- -k nomatch
Parsing of early options should stop at "--":
$ hg cat -- --config=hooks.pre-cat=false
--config=hooks.pre-cat=false: no such file in rev cb9a9f314b8b
[1]
$ hg cat -- --debugger
--debugger: no such file in rev cb9a9f314b8b
[1]
Unparsable form of early options:
$ hg cat --debugg
abort: option --debugger may not be abbreviated!
[255]
Parsing failure of early options should be detected before executing the
command:
$ hg log -b '--config=hooks.pre-log=false' default
abort: option --config may not be abbreviated!
[255]
$ hg log -b -R. default
abort: option -R has to be separated from other options (e.g. not -qR) and --repository may only be abbreviated as --repo!
[255]
$ hg log --cwd .. -b --cwd=. default
abort: option --cwd may not be abbreviated!
[255]
However, we can't prevent it from loading extensions and configs:
$ cat <<EOF > bad.py
> raise Exception('bad')
> EOF
$ hg log -b '--config=extensions.bad=bad.py' default
*** failed to import extension bad from bad.py: bad
abort: option --config may not be abbreviated!
[255]
$ mkdir -p badrepo/.hg
$ echo 'invalid-syntax' > badrepo/.hg/hgrc
$ hg log -b -Rbadrepo default
hg: parse error at badrepo/.hg/hgrc:1: invalid-syntax
[255]
$ hg log -b --cwd=inexistent default
abort: $ENOENT$: 'inexistent'
[255]
$ hg log -b '--config=ui.traceback=yes' 2>&1 | grep '^Traceback'
Traceback (most recent call last):
$ hg log -b '--config=profiling.enabled=yes' 2>&1 | grep -i sample
Sample count: .*|No samples recorded\. (re)
Early options can't be specified in [aliases] and [defaults] because they are
applied before the command name is resolved:
$ hg log -b '--config=alias.log=log --config=hooks.pre-log=false'
hg log: option -b not recognized
error in definition for alias 'log': --config may only be given on the command
line
[255]
$ hg log -b '--config=defaults.log=--config=hooks.pre-log=false'
abort: option --config may not be abbreviated!
[255]
Shell aliases bypass any command parsing rules but for the early one:
$ hg log -b '--config=alias.log=!echo howdy'
howdy
Early options must come first if HGPLAIN=+strictflags is specified:
(BUG: chg cherry-picks early options to pass them as a server command)
#if no-chg
$ HGPLAIN=+strictflags hg log -b --config='hooks.pre-log=false' default
abort: unknown revision '--config=hooks.pre-log=false'!
[255]
$ HGPLAIN=+strictflags hg log -b -R. default
abort: unknown revision '-R.'!
[255]
$ HGPLAIN=+strictflags hg log -b --cwd=. default
abort: unknown revision '--cwd=.'!
[255]
#endif
$ HGPLAIN=+strictflags hg log -b --debugger default
abort: unknown revision '--debugger'!
[255]
$ HGPLAIN=+strictflags hg log -b --config='alias.log=!echo pwned' default
abort: unknown revision '--config=alias.log=!echo pwned'!
[255]
$ HGPLAIN=+strictflags hg log --config='hooks.pre-log=false' -b default
abort: option --config may not be abbreviated!
[255]
$ HGPLAIN=+strictflags hg log -q --cwd=.. -b default
abort: option --cwd may not be abbreviated!
[255]
$ HGPLAIN=+strictflags hg log -q -R . -b default
abort: option -R has to be separated from other options (e.g. not -qR) and --repository may only be abbreviated as --repo!
[255]
$ HGPLAIN=+strictflags hg --config='hooks.pre-log=false' log -b default
abort: pre-log hook exited with status 1
[255]
$ HGPLAIN=+strictflags hg --cwd .. -q -Ra log -b default
0:cb9a9f314b8b
$ HGPLAIN=+strictflags hg --cwd .. -q --repository a log -b default
0:cb9a9f314b8b
$ HGPLAIN=+strictflags hg --cwd .. -q --repo a log -b default
0:cb9a9f314b8b
For compatibility reasons, HGPLAIN=+strictflags is not enabled by plain HGPLAIN:
$ HGPLAIN= hg log --config='hooks.pre-log=false' -b default
abort: pre-log hook exited with status 1
[255]
$ HGPLAINEXCEPT= hg log --cwd .. -q -Ra -b default
0:cb9a9f314b8b
[defaults]
$ hg cat a
a
$ cat >> $HGRCPATH <<EOF
> [defaults]
> cat = -r null
> EOF
$ hg cat a
a: no such file in rev 000000000000
[1]
$ cd "$TESTTMP"
OSError "No such file or directory" / "The system cannot find the path
specified" should include filename even when it is empty
$ hg -R a archive ''
abort: $ENOENT$: '' (no-windows !)
abort: $ENOTDIR$: '' (windows !)
[255]
#if no-outer-repo
No repo:
$ hg cat
abort: no repository found in '$TESTTMP' (.hg not found)!
[255]
#endif
#if rmcwd
Current directory removed:
$ mkdir $TESTTMP/repo1
$ cd $TESTTMP/repo1
$ rm -rf $TESTTMP/repo1
The output could be one of the following and something else:
chg: abort: failed to getcwd (errno = *) (glob)
abort: error getting current working directory: * (glob)
sh: 0: getcwd() failed: $ENOENT$
Since the exact behavior depends on the shell, only check it returns non-zero.
$ HGDEMANDIMPORT=disable hg version -q 2>/dev/null || false
[1]
#endif