Merge branch 'drive-prefix'

This topic branch allows us to specify absolute paths without the drive
prefix e.g. when cloning.

Example:

	C:\Users\me> git clone https://github.com/git/git \upstream-git

This will clone into a new directory C:\upstream-git, in line with how
Windows interprets absolute paths.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: Git for Windows Build Agent

compat/mingw.c

@@ -948,12 +948,20 @@ unsigned int sleep (unsigned int seconds)
 char *mingw_mktemp(char *template)
 {
 	wchar_t wtemplate[MAX_PATH];
+	int offset = 0;
+
 	/* we need to return the path, thus no long paths here! */
 	if (xutftowcs_path(wtemplate, template) < 0)
 		return NULL;
+
+	if (is_dir_sep(template[0]) && !is_dir_sep(template[1]) &&
+	    iswalpha(wtemplate[0]) && wtemplate[1] == L':') {
+		/* We have an absolute path missing the drive prefix */
+		offset = 2;
+	}
 	if (!_wmktemp(wtemplate))
 		return NULL;
-	if (xwcstoutf(template, wtemplate, strlen(template) + 1) < 0)
+	if (xwcstoutf(template, wtemplate + offset, strlen(template) + 1) < 0)
 		return NULL;
 	return template;
 }

t/t5580-clone-push-unc.sh

@@ -1,31 +1,40 @@
 #!/bin/sh
 
-test_description='various UNC path tests (Windows-only)'
+test_description='various Windows path tests'
 . ./test-lib.sh
 
 if ! test_have_prereq MINGW; then
-	skip_all='skipping UNC path tests, requires Windows'
+	skip_all='skipping Windows-specific path tests'
 	test_done
 fi
 
 UNCPATH="$(pwd)"
 case "$UNCPATH" in
 [A-Z]:*)
+	WITHOUTDRIVE="${UNCPATH#?:}"
 	# Use administrative share e.g. \\localhost\C$\git-sdk-64\usr\src\git
 	# (we use forward slashes here because MSYS2 and Git accept them, and
 	# they are easier on the eyes)
-	UNCPATH="//localhost/${UNCPATH%%:*}\$/${UNCPATH#?:}"
-	test -d "$UNCPATH" || {
-		skip_all='could not access administrative share; skipping'
-		test_done
-	}
+	UNCPATH="//localhost/${UNCPATH%%:*}\$$WITHOUTDRIVE"
 	;;
 *)
 	skip_all='skipping UNC path tests, cannot determine current path as UNC'
 	test_done
 	;;
 esac
 
+test_expect_success 'clone into absolute path lacking a drive prefix' '
+	USINGBACKSLASHES="$(echo "$WITHOUTDRIVE"/without-drive-prefix |
+		tr / \\)" &&
+	git clone . "$USINGBACKSLASHES" &&
+	test -f without-drive-prefix/.git/HEAD
+'
+
+test -d "$UNCPATH" || {
+	skip_all='could not access administrative share; skipping'
+	test_done
+}
+
 test_expect_success setup '
 	test_commit initial
 '