merge: make applyupdates() not mutate mresult argument
We have an extension at work that overrides `merge.applyupdates()` to
make it skip some writes and instead instruct the virtual filesystem
we use to get a different version. That override doesn't work
correctly when doing `hg co -m` and there's a modified file in the
dirstate that's deleted in the destination. That's because
`applyupdates()` mutates its `mresult` argument and our extension had
passed in a modified copied of `mresult` to the overridden function,
which resulted in the mutation not having any effect. This patch fixes
that by letting the caller (i.e. `merge._update()`) update `mresult`
with the extra actions instead. Besides fixing our internal extension,
that seems cleaner to me anyway (better to not mutate `mresult` only
in some cases and we can skip some of the logic if we're not going to
update the dirstate anyway).
Differential Revision: https://phab.mercurial-scm.org/D10830
/*
exewrapper.c - wrapper for calling a python script on Windows
Copyright 2012 Adrian Buehlmann <adrian@cadifra.com> and others
This software may be used and distributed according to the terms of the
GNU General Public License version 2 or any later version.
*/
#include <Python.h>
#include <stdio.h>
#include <tchar.h>
#include <windows.h>
#include "hgpythonlib.h"
#ifdef __GNUC__
int strcat_s(char *d, size_t n, const char *s)
{
return !strncat(d, s, n);
}
int strcpy_s(char *d, size_t n, const char *s)
{
return !strncpy(d, s, n);
}
#define _tcscpy_s strcpy_s
#define _tcscat_s strcat_s
#define _countof(array) (sizeof(array) / sizeof(array[0]))
#endif
static TCHAR pyscript[MAX_PATH + 10];
static TCHAR pyhome[MAX_PATH + 10];
static TCHAR pydllfile[MAX_PATH + 10];
int _tmain(int argc, TCHAR *argv[])
{
TCHAR *p;
int ret;
int i;
int n;
TCHAR **pyargv;
WIN32_FIND_DATA fdata;
HANDLE hfind;
const char *err;
HMODULE pydll;
void(__cdecl * Py_SetPythonHome)(TCHAR * home);
int(__cdecl * Py_Main)(int argc, TCHAR *argv[]);
#if PY_MAJOR_VERSION >= 3
_wputenv(L"PYTHONLEGACYWINDOWSSTDIO=1");
#endif
if (GetModuleFileName(NULL, pyscript, _countof(pyscript)) == 0) {
err = "GetModuleFileName failed";
goto bail;
}
p = _tcsrchr(pyscript, '.');
if (p == NULL) {
err = "malformed module filename";
goto bail;
}
*p = 0; /* cut trailing ".exe" */
_tcscpy_s(pyhome, _countof(pyhome), pyscript);
hfind = FindFirstFile(pyscript, &fdata);
if (hfind != INVALID_HANDLE_VALUE) {
/* pyscript exists, close handle */
FindClose(hfind);
} else {
/* file pyscript isn't there, take <pyscript>exe.py */
_tcscat_s(pyscript, _countof(pyscript), _T("exe.py"));
}
pydll = NULL;
p = _tcsrchr(pyhome, _T('\\'));
if (p == NULL) {
err = "can't find backslash in module filename";
goto bail;
}
*p = 0; /* cut at directory */
/* check for private Python of HackableMercurial */
_tcscat_s(pyhome, _countof(pyhome), _T("\\hg-python"));
hfind = FindFirstFile(pyhome, &fdata);
if (hfind != INVALID_HANDLE_VALUE) {
/* Path .\hg-python exists. We are probably in HackableMercurial
scenario, so let's load python dll from this dir. */
FindClose(hfind);
_tcscpy_s(pydllfile, _countof(pydllfile), pyhome);
_tcscat_s(pydllfile, _countof(pydllfile),
_T("\\") _T(HGPYTHONLIB) _T(".dll"));
pydll = LoadLibrary(pydllfile);
if (pydll == NULL) {
err = "failed to load private Python DLL " HGPYTHONLIB
".dll";
goto bail;
}
Py_SetPythonHome =
(void *)GetProcAddress(pydll, "Py_SetPythonHome");
if (Py_SetPythonHome == NULL) {
err = "failed to get Py_SetPythonHome";
goto bail;
}
Py_SetPythonHome(pyhome);
}
if (pydll == NULL) {
pydll = LoadLibrary(_T(HGPYTHONLIB) _T(".dll"));
if (pydll == NULL) {
err = "failed to load Python DLL " HGPYTHONLIB ".dll";
goto bail;
}
}
Py_Main = (void *)GetProcAddress(pydll, "Py_Main");
if (Py_Main == NULL) {
err = "failed to get Py_Main";
goto bail;
}
/*
Only add the pyscript to the args, if it's not already there. It may
already be there, if the script spawned a child process of itself, in
the same way as it got called, that is, with the pyscript already in
place. So we optionally accept the pyscript as the first argument
(argv[1]), letting our exe taking the role of the python interpreter.
*/
if (argc >= 2 && _tcscmp(argv[1], pyscript) == 0) {
/*
pyscript is already in the args, so there is no need to copy
the args and we can directly call the python interpreter with
the original args.
*/
return Py_Main(argc, argv);
}
/*
Start assembling the args for the Python interpreter call. We put the
name of our exe (argv[0]) in the position where the python.exe
canonically is, and insert the pyscript next.
*/
pyargv = malloc((argc + 5) * sizeof(TCHAR *));
if (pyargv == NULL) {
err = "not enough memory";
goto bail;
}
n = 0;
pyargv[n++] = argv[0];
pyargv[n++] = pyscript;
/* copy remaining args from the command line */
for (i = 1; i < argc; i++)
pyargv[n++] = argv[i];
/* argv[argc] is guaranteed to be NULL, so we forward that guarantee */
pyargv[n] = NULL;
ret = Py_Main(n, pyargv); /* The Python interpreter call */
free(pyargv);
return ret;
bail:
fprintf(stderr, "abort: %s\n", err);
return 255;
}