fast-import: introduce 'done' command

Add a 'done' command that causes fast-import to stop reading from the
stream and exit.

If the new --done command line flag was passed on the command line
(or a "feature done" declaration included at the start of the stream),
make the 'done' command mandatory.  So "git fast-import --done"'s
input format will be prefix-free, making errors easier to detect when
they show up as early termination at some convenient time of the
upstream of a pipe writing to fast-import.

Another possible application of the 'done' command would to be allow a
fast-import stream that is only a small part of a larger encapsulating
stream to be easily parsed, leaving the file offset after the "done\n"
so the other application can pick up from there.  This patch does not
teach fast-import to do that --- fast-import still uses buffered input
(stdio).

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 249249aac7b2b9def824794b2bf71e2c7fe497ce..0fc68a911e9659e1d06355e872d2d84359ec9e9b 100644 (file)
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -101,6 +101,12 @@ OPTIONS
        when the `cat-blob` command is encountered in the stream.
        The default behaviour is to write to `stdout`.
 
        when the `cat-blob` command is encountered in the stream.
        The default behaviour is to write to `stdout`.
 

+--done::
+       Require a `done` command at the end of the stream.
+       This option might be useful for detecting errors that
+       cause the frontend to terminate before it has started to
+       write a stream.
+

 --export-pack-edges=<file>::
        After creating a packfile, print a line of data to
        <file> listing the filename of the packfile and the last
 --export-pack-edges=<file>::
        After creating a packfile, print a line of data to
        <file> listing the filename of the packfile and the last


@@ -330,6 +336,11 @@ and control the current import process.  More detailed discussion
        standard output.  This command is optional and is not needed
        to perform an import.
 
        standard output.  This command is optional and is not needed
        to perform an import.
 

+`done`::
+       Marks the end of the stream. This command is optional
+       unless the `done` feature was requested using the
+       `--done` command line option or `feature done` command.
+

 `cat-blob`::
        Causes fast-import to print a blob in 'cat-file --batch'
        format to the file descriptor set with `--cat-blob-fd` or
 `cat-blob`::
        Causes fast-import to print a blob in 'cat-file --batch'
        format to the file descriptor set with `--cat-blob-fd` or


@@ -1015,6 +1026,11 @@ notes::
        Versions of fast-import not supporting notes will exit
        with a message indicating so.
 
        Versions of fast-import not supporting notes will exit
        with a message indicating so.
 

+done::
+       Error out if the stream ends without a 'done' command.
+       Without this feature, errors causing the frontend to end
+       abruptly at a convenient point in the stream can go
+       undetected.

 
 `option`
 ~~~~~~~~
 
 `option`
 ~~~~~~~~


@@ -1044,6 +1060,15 @@ not be passed as option:
 * cat-blob-fd
 * force
 
 * cat-blob-fd
 * force
 

+`done`
+~~~~~~
+If the `done` feature is not in use, treated as if EOF was read.
+This can be used to tell fast-import to finish early.
+
+If the `--done` command line option or `feature done` command is
+in use, the `done` command is mandatory and marks the end of the
+stream.
+

 Crash Reports
 -------------
 If fast-import is supplied invalid input it will terminate with a
 Crash Reports
 -------------
 If fast-import is supplied invalid input it will terminate with a

diff --git a/fast-import.c b/fast-import.c
index 78d978684da2e2b79340c138e1b6300100df1221..8a8a91589782203e9d7455921a80a47d7a7b3710 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -354,6 +354,7 @@ static unsigned int cmd_save = 100;
 static uintmax_t next_mark;
 static struct strbuf new_data = STRBUF_INIT;
 static int seen_data_command;
 static uintmax_t next_mark;
 static struct strbuf new_data = STRBUF_INIT;
 static int seen_data_command;

+static int require_explicit_termination;

 
 /* Signal handling */
 static volatile sig_atomic_t checkpoint_requested;
 
 /* Signal handling */
 static volatile sig_atomic_t checkpoint_requested;


@@ -3139,6 +3140,8 @@ static int parse_one_feature(const char *feature, int from_stream)
                relative_marks_paths = 1;
        } else if (!strcmp(feature, "no-relative-marks")) {
                relative_marks_paths = 0;
                relative_marks_paths = 1;
        } else if (!strcmp(feature, "no-relative-marks")) {
                relative_marks_paths = 0;

+       } else if (!strcmp(feature, "done")) {
+               require_explicit_termination = 1;

        } else if (!strcmp(feature, "force")) {
                force_update = 1;
        } else if (!strcmp(feature, "notes") || !strcmp(feature, "ls")) {
        } else if (!strcmp(feature, "force")) {
                force_update = 1;
        } else if (!strcmp(feature, "notes") || !strcmp(feature, "ls")) {


@@ -3288,6 +3291,8 @@ int main(int argc, const char **argv)
                        parse_reset_branch();
                else if (!strcmp("checkpoint", command_buf.buf))
                        parse_checkpoint();
                        parse_reset_branch();
                else if (!strcmp("checkpoint", command_buf.buf))
                        parse_checkpoint();

+               else if (!strcmp("done", command_buf.buf))
+                       break;

                else if (!prefixcmp(command_buf.buf, "progress "))
                        parse_progress();
                else if (!prefixcmp(command_buf.buf, "feature "))
                else if (!prefixcmp(command_buf.buf, "progress "))
                        parse_progress();
                else if (!prefixcmp(command_buf.buf, "feature "))


@@ -3307,6 +3312,9 @@ int main(int argc, const char **argv)
        if (!seen_data_command)
                parse_argv();
 
        if (!seen_data_command)
                parse_argv();
 

+       if (require_explicit_termination && feof(stdin))
+               die("stream ends early");
+

        end_packfile();
 
        dump_branches();
        end_packfile();
 
        dump_branches();

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 6b1ba6c858562b7c085951fb1d69d4d2371e866c..526231bbeb1eba8cbcc9d1b2c32dbd7b9be4b342 100755 (executable)
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -2197,6 +2197,48 @@ test_expect_success 'R: quiet option results in no stats being output' '
     test_cmp empty output
 '
 
     test_cmp empty output
 '
 

+test_expect_success 'R: feature done means terminating "done" is mandatory' '
+       echo feature done | test_must_fail git fast-import &&
+       test_must_fail git fast-import --done </dev/null
+'
+
+test_expect_success 'R: terminating "done" with trailing gibberish is ok' '
+       git fast-import <<-\EOF &&
+       feature done
+       done
+       trailing gibberish
+       EOF
+       git fast-import <<-\EOF
+       done
+       more trailing gibberish
+       EOF
+'
+
+test_expect_success 'R: terminating "done" within commit' '
+       cat >expect <<-\EOF &&
+       OBJID
+       :000000 100644 OBJID OBJID A    hello.c
+       :000000 100644 OBJID OBJID A    hello2.c
+       EOF
+       git fast-import <<-EOF &&
+       commit refs/heads/done-ends
+       committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+       data <<EOT
+       Commit terminated by "done" command
+       EOT
+       M 100644 inline hello.c
+       data <<EOT
+       Hello, world.
+       EOT
+       C hello.c hello2.c
+       done
+       EOF
+       git rev-list done-ends |
+       git diff-tree -r --stdin --root --always |
+       sed -e "s/$_x40/OBJID/g" >actual &&
+       test_cmp expect actual
+'
+

 cat >input <<EOF
 option git non-existing-option
 EOF
 cat >input <<EOF
 option git non-existing-option
 EOF