mingw: drop Windows 7-specific work-around

In ac33519 (mingw: restrict file handle inheritance only on Windows
7 and later, 2019-11-22), I introduced code to safe-guard the
defense-in-depth handling that restricts handles' inheritance so that it
would work with Windows 7, too.

Let's revert this patch: Git for Windows dropped supporting Windows 7 (and
Windows 8) directly after Git for Windows v2.46.2. For full details, see
https://gitforwindows.org/requirements#windows-version.

Actually, on second thought: revert only the part that makes this handle
inheritance restriction logic optional and that suggests to open a bug
report if it fails, but keep the fall-back to try again without said
logic: There have been a few false positives over the past few years
(where the warning was triggered e.g. because Defender was still
accessing a file that Git wanted to overwrite), and the fall-back logic
seems to have helped occasionally in such situations.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Documentation/config/core.adoc

@@ -704,12 +704,6 @@ core.unsetenvvars::
 	Defaults to `PERL5LIB` to account for the fact that Git for
 	Windows insists on using its own Perl interpreter.
 
-core.restrictinheritedhandles::
-	Windows-only: override whether spawned processes inherit only standard
-	file handles (`stdin`, `stdout` and `stderr`) or all handles. Can be
-	`auto`, `true` or `false`. Defaults to `auto`, which means `true` on
-	Windows 7 and later, and `false` on older Windows versions.
-
 core.createObject::
 	You can set this to 'link', in which case a hardlink followed by
 	a delete of the source are used to make sure that object creation

compat/mingw.c

@@ -274,7 +274,6 @@ enum hide_dotfiles_type {
 	HIDE_DOTFILES_DOTGITONLY
 };
 
-static int core_restrict_inherited_handles = -1;
 static enum hide_dotfiles_type hide_dotfiles = HIDE_DOTFILES_DOTGITONLY;
 static char *unset_environment_variables;
 int core_fscache;
@@ -325,15 +324,6 @@ int mingw_core_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (!strcmp(var, "core.restrictinheritedhandles")) {
-		if (value && !strcasecmp(value, "auto"))
-			core_restrict_inherited_handles = -1;
-		else
-			core_restrict_inherited_handles =
-				git_config_bool(var, value);
-		return 0;
-	}
-
 	return 0;
 }
 
@@ -2060,7 +2050,6 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 			      const char *dir, const char *prepend_cmd,
 			      int fhin, int fhout, int fherr)
 {
-	static int restrict_handle_inheritance = -1;
 	STARTUPINFOEXW si;
 	PROCESS_INFORMATION pi;
 	LPPROC_THREAD_ATTRIBUTE_LIST attr_list = NULL;
@@ -2080,16 +2069,6 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	/* Make sure to override previous errors, if any */
 	errno = 0;
 
-	if (restrict_handle_inheritance < 0)
-		restrict_handle_inheritance = core_restrict_inherited_handles;
-	/*
-	 * The following code to restrict which handles are inherited seems
-	 * to work properly only on Windows 7 and later, so let's disable it
-	 * on Windows Vista and 2008.
-	 */
-	if (restrict_handle_inheritance < 0)
-		restrict_handle_inheritance = GetVersion() >> 16 >= 7601;
-
 	do_unset_environment_variables();
 
 	/* Determine whether or not we are associated to a console */
@@ -2195,7 +2174,7 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	wenvblk = make_environment_block(deltaenv);
 
 	memset(&pi, 0, sizeof(pi));
-	if (restrict_handle_inheritance && stdhandles_count &&
+	if (stdhandles_count &&
 	    (InitializeProcThreadAttributeList(NULL, 1, 0, &size) ||
 	     GetLastError() == ERROR_INSUFFICIENT_BUFFER) &&
 	    (attr_list = (LPPROC_THREAD_ATTRIBUTE_LIST)
@@ -2216,52 +2195,13 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 			     &si.StartupInfo, &pi);
 
 	/*
-	 * On Windows 2008 R2, it seems that specifying certain types of handles
-	 * (such as FILE_TYPE_CHAR or FILE_TYPE_PIPE) will always produce an
-	 * error. Rather than playing finicky and fragile games, let's just try
-	 * to detect this situation and simply try again without restricting any
-	 * handle inheritance. This is still better than failing to create
-	 * processes.
+	 * On the off-chance that something with the file handle restriction
+	 * went wrong, silently fall back to trying without it.
 	 */
-	if (!ret && restrict_handle_inheritance && stdhandles_count) {
+	if (!ret && stdhandles_count) {
 		DWORD err = GetLastError();
 		struct strbuf buf = STRBUF_INIT;
 
-		if (err != ERROR_NO_SYSTEM_RESOURCES &&
-		    /*
-		     * On Windows 7 and earlier, handles on pipes and character
-		     * devices are inherited automatically, and cannot be
-		     * specified in the thread handle list. Rather than trying
-		     * to catch each and every corner case (and running the
-		     * chance of *still* forgetting a few), let's just fall
-		     * back to creating the process without trying to limit the
-		     * handle inheritance.
-		     */
-		    !(err == ERROR_INVALID_PARAMETER &&
-		      GetVersion() >> 16 < 9200) &&
-		    !getenv("SUPPRESS_HANDLE_INHERITANCE_WARNING")) {
-			DWORD fl = 0;
-			int i;
-
-			setenv("SUPPRESS_HANDLE_INHERITANCE_WARNING", "1", 1);
-
-			for (i = 0; i < stdhandles_count; i++) {
-				HANDLE h = stdhandles[i];
-				strbuf_addf(&buf, "handle #%d: %p (type %lx, "
-					    "handle info (%d) %lx\n", i, h,
-					    GetFileType(h),
-					    GetHandleInformation(h, &fl),
-					    fl);
-			}
-			strbuf_addstr(&buf, "\nThis is a bug; please report it "
-				      "at\nhttps://github.com/git-for-windows/"
-				      "git/issues/new\n\n"
-				      "To suppress this warning, please set "
-				      "the environment variable\n\n"
-				      "\tSUPPRESS_HANDLE_INHERITANCE_WARNING=1"
-				      "\n");
-		}
-		restrict_handle_inheritance = 0;
 		flags &= ~EXTENDED_STARTUPINFO_PRESENT;
 		ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
 				     TRUE, flags, wenvblk, dir ? wdir : NULL,