fast-import: Introduce --import-marks-if-exists

When a frontend uses a marks file to ensure its state persists between
runs, it may represent "clean slate" when bootstrapping with "no marks
yet". In such a case, feeding the last state with --import-marks and
saving the state after the current run with --export-marks would be a
natural thing to do.

The --import-marks option however errors out when the specified marks file
doesn't exist; this makes bootstrapping a bit difficult.  The location of
the marks file becomes backend-dependent when --relative-marks is in
effect, and the frontend cannot check for the existence of the file in
such a case.

The --import-marks-if-exists option does the same thing as --import-marks
but does not flag an error if the named file does not exist yet to help
these frontends.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index f56dfcabb96d1510abfd61a13c36135f3824b744..32a062c991bba220f0e623afb9e89d75b3b23ed8 100644 (file)
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -78,6 +78,10 @@ OPTIONS
        set of marks.  If a mark is defined to different values,
        the last file wins.
 
+--import-marks-if-exists=<file>::
+       Like --import-marks but instead of erroring out, silently
+       skips the file if it does not exist.
+
 --relative-marks::
        After specifying --relative-marks= the paths specified
        with --import-marks= and --export-marks= are relative

diff --git a/fast-import.c b/fast-import.c
index 785776086ccc22dcd5488e3ac0bad3318f57043e..c525fdaac617541852415cdfa5f7c1c9ecfe4df5 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -329,6 +329,7 @@ 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 import_marks_file_ignore_missing;
 static int relative_marks_paths;
 
 /* Our last blob */
@@ -1795,7 +1796,11 @@ static void read_marks(void)
 {
        char line[512];
        FILE *f = fopen(import_marks_file, "r");
-       if (!f)
+       if (f)
+               ;
+       else if (import_marks_file_ignore_missing && errno == ENOENT)
+               return; /* Marks file does not exist */
+       else
                die_errno("cannot read '%s'", import_marks_file);
        while (fgets(line, sizeof(line), f)) {
                uintmax_t mark;
@@ -2861,7 +2866,8 @@ static char* make_fast_import_path(const char *path)
        return strbuf_detach(&abs_path, NULL);
 }
 
-static void option_import_marks(const char *marks, int from_stream)
+static void option_import_marks(const char *marks,
+                                       int from_stream, int ignore_missing)
 {
        if (import_marks_file) {
                if (from_stream)
@@ -2875,6 +2881,7 @@ static void option_import_marks(const char *marks, int from_stream)
        import_marks_file = make_fast_import_path(marks);
        safe_create_leading_directories_const(import_marks_file);
        import_marks_file_from_stream = from_stream;
+       import_marks_file_ignore_missing = ignore_missing;
 }
 
 static void option_date_format(const char *fmt)
@@ -2974,7 +2981,10 @@ static int parse_one_feature(const char *feature, int from_stream)
        if (!prefixcmp(feature, "date-format=")) {
                option_date_format(feature + 12);
        } else if (!prefixcmp(feature, "import-marks=")) {
-               option_import_marks(feature + 13, from_stream);
+               option_import_marks(feature + 13, from_stream, 0);
+       } else if (!prefixcmp(feature, "import-marks-if-exists=")) {
+               option_import_marks(feature + strlen("import-marks-if-exists="),
+                                       from_stream, 1);
        } else if (!prefixcmp(feature, "export-marks=")) {
                option_export_marks(feature + 13);
        } else if (!strcmp(feature, "cat-blob")) {

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 222d1059ef99879d3db387be798f973fb093f53e..870e55b0beece8dfa85b2dd91c620ce8786043ce 100755 (executable)
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -1706,6 +1706,61 @@ test_expect_success \
     'cat input | git fast-import --export-marks=other.marks &&
     grep :1 other.marks'
 
+test_expect_success 'R: catch typo in marks file name' '
+       test_must_fail git fast-import --import-marks=nonexistent.marks </dev/null &&
+       echo "feature import-marks=nonexistent.marks" |
+       test_must_fail git fast-import
+'
+
+test_expect_success 'R: import and output marks can be the same file' '
+       rm -f io.marks &&
+       blob=$(echo hi | git hash-object --stdin) &&
+       cat >expect <<-EOF &&
+       :1 $blob
+       :2 $blob
+       EOF
+       git fast-import --export-marks=io.marks <<-\EOF &&
+       blob
+       mark :1
+       data 3
+       hi
+
+       EOF
+       git fast-import --import-marks=io.marks --export-marks=io.marks <<-\EOF &&
+       blob
+       mark :2
+       data 3
+       hi
+
+       EOF
+       test_cmp expect io.marks
+'
+
+test_expect_success 'R: --import-marks=foo --output-marks=foo to create foo fails' '
+       rm -f io.marks &&
+       test_must_fail git fast-import --import-marks=io.marks --export-marks=io.marks <<-\EOF
+       blob
+       mark :1
+       data 3
+       hi
+
+       EOF
+'
+
+test_expect_success 'R: --import-marks-if-exists' '
+       rm -f io.marks &&
+       blob=$(echo hi | git hash-object --stdin) &&
+       echo ":1 $blob" >expect &&
+       git fast-import --import-marks-if-exists=io.marks --export-marks=io.marks <<-\EOF &&
+       blob
+       mark :1
+       data 3
+       hi
+
+       EOF
+       test_cmp expect io.marks
+'
+
 cat >input << EOF
 feature import-marks=marks.out
 feature export-marks=marks.new