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Merge branch 'js/mingw-redirect-std-handles'
MinGW updates. * js/mingw-redirect-std-handles: mingw: document the standard handle redirection mingw: optionally redirect stderr/stdout via the same handle mingw: add experimental feature to redirect standard handles
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‎Documentation/git.txt‎

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@@ -709,6 +709,24 @@ of clones and fetches.
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the background which do not want to cause lock contention with
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other operations on the repository. Defaults to `1`.
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`GIT_REDIRECT_STDIN`::
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`GIT_REDIRECT_STDOUT`::
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`GIT_REDIRECT_STDERR`::
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Windows-only: allow redirecting the standard input/output/error
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handles to paths specified by the environment variables. This is
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particularly useful in multi-threaded applications where the
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canonical way to pass standard handles via `CreateProcess()` is
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not an option because it would require the handles to be marked
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inheritable (and consequently *every* spawned process would
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inherit them, possibly blocking regular Git operations). The
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primary intended use case is to use named pipes for communication
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(e.g. `\\.\pipe\my-git-stdin-123`).
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+
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Two special values are supported: `off` will simply close the
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corresponding standard handle, and if `GIT_REDIRECT_STDERR` is
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`2>&1`, standard error will be redirected to the same handle as
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standard output.
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Discussion[[Discussion]]
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------------------------
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‎compat/mingw.c‎

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@@ -2139,13 +2139,71 @@ static char *wcstoutfdup_startup(char *buffer, const wchar_t *wcs, size_t len)
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return memcpy(malloc_startup(len), buffer, len);
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}
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static void maybe_redirect_std_handle(const wchar_t *key, DWORD std_id, int fd,
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DWORD desired_access, DWORD flags)
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{
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DWORD create_flag = fd ? OPEN_ALWAYS : OPEN_EXISTING;
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wchar_t buf[MAX_PATH];
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DWORD max = ARRAY_SIZE(buf);
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HANDLE handle;
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DWORD ret = GetEnvironmentVariableW(key, buf, max);
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if (!ret || ret >= max)
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return;
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/* make sure this does not leak into child processes */
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SetEnvironmentVariableW(key, NULL);
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if (!wcscmp(buf, L"off")) {
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close(fd);
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handle = GetStdHandle(std_id);
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if (handle != INVALID_HANDLE_VALUE)
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CloseHandle(handle);
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return;
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}
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if (std_id == STD_ERROR_HANDLE && !wcscmp(buf, L"2>&1")) {
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handle = GetStdHandle(STD_OUTPUT_HANDLE);
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if (handle == INVALID_HANDLE_VALUE) {
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close(fd);
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handle = GetStdHandle(std_id);
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if (handle != INVALID_HANDLE_VALUE)
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CloseHandle(handle);
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} else {
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int new_fd = _open_osfhandle((intptr_t)handle, O_BINARY);
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SetStdHandle(std_id, handle);
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dup2(new_fd, fd);
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/* do *not* close the new_fd: that would close stdout */
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}
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return;
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}
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handle = CreateFileW(buf, desired_access, 0, NULL, create_flag,
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flags, NULL);
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if (handle != INVALID_HANDLE_VALUE) {
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int new_fd = _open_osfhandle((intptr_t)handle, O_BINARY);
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SetStdHandle(std_id, handle);
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dup2(new_fd, fd);
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close(new_fd);
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}
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}
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static void maybe_redirect_std_handles(void)
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{
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maybe_redirect_std_handle(L"GIT_REDIRECT_STDIN", STD_INPUT_HANDLE, 0,
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GENERIC_READ, FILE_ATTRIBUTE_NORMAL);
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maybe_redirect_std_handle(L"GIT_REDIRECT_STDOUT", STD_OUTPUT_HANDLE, 1,
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GENERIC_WRITE, FILE_ATTRIBUTE_NORMAL);
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maybe_redirect_std_handle(L"GIT_REDIRECT_STDERR", STD_ERROR_HANDLE, 2,
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GENERIC_WRITE, FILE_FLAG_NO_BUFFERING);
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}
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void mingw_startup(void)
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{
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int i, maxlen, argc;
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char *buffer;
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wchar_t **wenv, **wargv;
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_startupinfo si;
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maybe_redirect_std_handles();
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/* get wide char arguments and environment */
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si.newmode = 0;
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if (__wgetmainargs(&argc, &wargv, &wenv, _CRT_glob, &si) < 0)

‎t/t0001-init.sh‎

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@@ -453,4 +453,16 @@ test_expect_success 're-init from a linked worktree' '
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)
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'
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test_expect_success MINGW 'redirect std handles' '
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GIT_REDIRECT_STDOUT=output.txt git rev-parse --git-dir &&
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test .git = "$(cat output.txt)" &&
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test -z "$(GIT_REDIRECT_STDOUT=off git rev-parse --git-dir)" &&
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test_must_fail env \
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GIT_REDIRECT_STDOUT=output.txt \
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GIT_REDIRECT_STDERR="2>&1" \
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git rev-parse --git-dir --verify refs/invalid &&
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printf ".git\nfatal: Needed a single revision\n" >expect &&
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test_cmp expect output.txt
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'
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test_done

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