Merge branch 'en/fast-imexport-nested-tags'

Updates to fast-import/export.

* en/fast-imexport-nested-tags:
  fast-export: handle nested tags
  t9350: add tests for tags of things other than a commit
  fast-export: allow user to request tags be marked with --mark-tags
  fast-export: add support for --import-marks-if-exists
  fast-import: add support for new 'alias' command
  fast-import: allow tags to be identified by mark labels
  fast-import: fix handling of deleted tags
  fast-export: fix exporting a tag and nothing else

2 files changed, 36 insertions, 4 deletions

diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index 784e934..37634bf 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -75,11 +75,20 @@ produced incorrect results if you gave these options.
 	Before processing any input, load the marks specified in
 	<file>.  The input file must exist, must be readable, and
 	must use the same format as produced by --export-marks.
+
+--mark-tags::
+	In addition to labelling blobs and commits with mark ids, also
+	label tags.  This is useful in conjunction with
+	`--export-marks` and `--import-marks`, and is also useful (and
+	necessary) for exporting of nested tags.  It does not hurt
+	other cases and would be the default, but many fast-import
+	frontends are not prepared to accept tags with mark
+	identifiers.
 +
-Any commits that have already been marked will not be exported again.
-If the backend uses a similar --import-marks file, this allows for
-incremental bidirectional exporting of the repository by keeping the
-marks the same across runs.
+Any commits (or tags) that have already been marked will not be
+exported again.  If the backend uses a similar --import-marks file,
+this allows for incremental bidirectional exporting of the repository
+by keeping the marks the same across runs.
 
 --fake-missing-tagger::
 	Some old repositories have tags without a tagger.  The
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 0bb2762..a3f1e0c 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -337,6 +337,13 @@ and control the current import process.  More detailed discussion
 	`commit` command.  This command is optional and is not
 	needed to perform an import.
 
+`alias`::
+	Record that a mark refers to a given object without first
+	creating any new object.  Using --import-marks and referring
+	to missing marks will cause fast-import to fail, so aliases
+	can provide a way to set otherwise pruned commits to a valid
+	value (e.g. the nearest non-pruned ancestor).
+
 `checkpoint`::
 	Forces fast-import to close the current packfile, generate its
 	unique SHA-1 checksum and index, and start a new packfile.
@@ -774,6 +781,7 @@ lightweight (non-annotated) tags see the `reset` command below.
 
 ....
 	'tag' SP <name> LF
+	mark?
 	'from' SP <commit-ish> LF
 	original-oid?
 	'tagger' (SP <name>)? SP LT <email> GT SP <when> LF
@@ -913,6 +921,21 @@ a data chunk which does not have an LF as its last byte.
 +
 The `LF` after `<delim> LF` is optional (it used to be required).
 
+`alias`
+~~~~~~~
+Record that a mark refers to a given object without first creating any
+new object.
+
+....
+	'alias' LF
+	mark
+	'to' SP <commit-ish> LF
+	LF?
+....
+
+For a detailed description of `<commit-ish>` see above under `from`.
+
+
 `checkpoint`
 ~~~~~~~~~~~~
 Forces fast-import to close the current packfile, start a new one, and to