fast-import: add (non-)relative-marks feature

After specifying 'feature relative-marks' the paths specified with
'feature import-marks' and 'feature export-marks' are relative to an
internal directory in the current repository.

In git-fast-import this means that the paths are relative to the
'.git/info/fast-import' directory. However, other importers may use a
different location.

Add 'feature non-relative-marks' to disable this behavior, this way
it is possible to, for example, specify the import-marks location as
relative, and the export-marks location as non-relative.

Also add tests to verify this behavior.

Cc: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-fast-import.txt

@@ -75,6 +75,20 @@ OPTIONS
 	set of marks.  If a mark is defined to different values,
 	the last file wins.
 
+--relative-marks::
+	After specifying --relative-marks= the paths specified
+	with --import-marks= and --export-marks= are relative
+	to an internal directory in the current repository.
+	In git-fast-import this means that the paths are relative
+	to the .git/info/fast-import directory. However, other
+	importers may use a different location.
+
+--no-relative-marks::
+	Negates a previous --relative-marks. Allows for combining
+	relative and non-relative marks by interweaving
+	--(no-)-relative-marks= with the --(import|export)-marks=
+	options.
+
 --export-pack-edges=<file>::
 	After creating a packfile, print a line of data to
 	<file> listing the filename of the packfile and the last
@@ -875,6 +889,8 @@ The following features are currently supported:
 * date-format
 * import-marks
 * export-marks
+* relative-marks
+* no-relative-marks
 * force
 
 The import-marks behaves differently from when it is specified as

fast-import.c

@@ -323,6 +323,7 @@ static struct mark_set *marks;
 static const char *export_marks_file;
 static const char *import_marks_file;
 static int import_marks_file_from_stream;
+static int relative_marks_paths;
 
 /* Our last blob */
 static struct last_object last_blob = { STRBUF_INIT, 0, 0, 0 };
@@ -2470,6 +2471,16 @@ static void parse_progress(void)
 	skip_optional_lf();
 }
 
+static char* make_fast_import_path(const char *path)
+{
+	struct strbuf abs_path = STRBUF_INIT;
+
+	if (!relative_marks_paths || is_absolute_path(path))
+		return xstrdup(path);
+	strbuf_addf(&abs_path, "%s/info/fast-import/%s", get_git_dir(), path);
+	return strbuf_detach(&abs_path, NULL);
+}
+
 static void option_import_marks(const char *marks, int from_stream)
 {
 	if (import_marks_file) {
@@ -2481,7 +2492,7 @@ static void option_import_marks(const char *marks, int from_stream)
 			read_marks();
 	}
 
-	import_marks_file = xstrdup(marks);
+	import_marks_file = make_fast_import_path(marks);
 	import_marks_file_from_stream = from_stream;
 }
 
@@ -2516,7 +2527,7 @@ static void option_active_branches(const char *branches)
 
 static void option_export_marks(const char *marks)
 {
-	export_marks_file = xstrdup(marks);
+	export_marks_file = make_fast_import_path(marks);
 }
 
 static void option_export_pack_edges(const char *edges)
@@ -2557,6 +2568,10 @@ static int parse_one_feature(const char *feature, int from_stream)
 		option_import_marks(feature + 13, from_stream);
 	} else if (!prefixcmp(feature, "export-marks=")) {
 		option_export_marks(feature + 13);
+	} else if (!prefixcmp(feature, "relative-marks")) {
+		relative_marks_paths = 1;
+	} else if (!prefixcmp(feature, "no-relative-marks")) {
+		relative_marks_paths = 0;
 	} else if (!prefixcmp(feature, "force")) {
 		force_update = 1;
 	} else {

t/t9300-fast-import.sh

@@ -1346,6 +1346,31 @@ test_expect_success 'R: multiple --import-marks= should be honoured' '
     test_cmp marks.out combined.marks
 '
 
+cat >input <<EOF
+feature relative-marks
+feature import-marks=relative.in
+feature export-marks=relative.out
+EOF
+
+test_expect_success 'R: feature relative-marks should be honoured' '
+    mkdir -p .git/info/fast-import/ &&
+    cp marks.new .git/info/fast-import/relative.in &&
+    git fast-import <input &&
+    test_cmp marks.new .git/info/fast-import/relative.out
+'
+
+cat >input <<EOF
+feature relative-marks
+feature import-marks=relative.in
+feature no-relative-marks
+feature export-marks=non-relative.out
+EOF
+
+test_expect_success 'R: feature no-relative-marks should be honoured' '
+    git fast-import <input &&
+    test_cmp marks.new non-relative.out
+'
+
 cat >input << EOF
 option git quiet
 blob