Hi,
(Feel free to put this on hold until v1.6.5 is released. In any case,
I'm going to Berlin for the weekend, and don't expect to read much
email...)
Here is the 7th iteration of the git-notes series. Changes in this
iteration are as follows:
- Rebased onto current 'next'
- Patch 1: Include minor leak fix
- Patch 10: Rename free_commit_notes() to free_notes() (Notes are
no longer bound to commits only, see patch 15 for details)
- Patch 12: Remove tests that are invalidated by concatenation code
in patch 13.
Overall, I consider the 12 first patches fairly stable at this point.
There's also a slew of new patches, that has more of an RFC status:
- Patches 13-14: Concatenation of multiple notes annotating the same
commit/object. This was originally suggested by mugwump many months
ago, and the suggestion was re-iterated by Dscho. This change has a
minor perfomance impact (see [1]), but I still think it's worth it.
- Patch 15: Allow notes to be attached to any object (not just commits).
Rename get_commit_notes() to format_note() to reflect this change.
- Patch 16-19: Expand notes API in preparation for querying and
manipulating notes from elsewhere in Git (see patch 22 for examples).
- Patch 20: Add a new notes_tree struct, and use it as the first
parameter to all functions in the notes API. This allows API users to
maintain their own (multiple, concurrent) notes trees (see patch 22
for an example). We still have a default notes tree in notes.c as a
fallback (when NULL is passed as to an API function).
- Patch 21: The default behaviour when there are multiple notes for a
given object is to concatenate them. However, some callers (see patch
22) want to tweak this behaviour. This patch defines a new function
type: combine_notes_fn, for combining two notes that reference the
same object. The notes API is then expanded to allow the caller to
specify a suitable combine_notes_fn. For convenience, three simple
combine_notes functions are available in the notes API:
- combine_notes_concatenate(): Concatenates the contents of the two
notes. (This is the default behaviour)
- combine_notes_overwrite(): Overwrite the existing note with the
new note.
- combine_notes_ignore(): Keep the existing note, and ignore the new
note.
- Patch 22: This teaches fast-import to use the new notes API when
adding note objects to a commit. Since adding a note to a notes tree
might cause restructuring of that notes tree, the note objects must
be handled differently from regular blobs.
There are some testcases for the new behaviour in this patch, but not
enough. These will be added later.
This patch is still very much in RFC mode...
Although this iteration brings the jh/notes topic towards feature-
completion, there are still some things left to do before I consider
the git notes feature fully complete:
- Builtin-ify git-notes shell script to take advantage of notes API
- Garbage-collect notes whose referenced objects are unreachable
- Handle note objects that are not blobs, but trees (e.g.
refs/notes/<topic>:<commit>/<subtopic>)
- Add a simple notation for referring to an object's note (e.g.
"<object>^{note}")
- Probably more that I haven't thought of yet...
However, It might be a good idea to consider merging the early/stable
parts of jh/notes, instead of waiting for everything to complete.
Have fun! :)
...Johan
[1] Performance impact of the concatenation rewrite.
In order to concatenate notes correctly, the tree traversal code must be
changed to more proactively unpack subtree entries (so that we can safely
determine whether there are multiple notes for a given key).
As before, the test case is as follows:
Linux kernel repo with 157101 commits, 1 note per commit, organized into
various fanout schemes. Hardware is Intel Core 2 Quad with 4GB RAM.
Algorithm / Notes tree git log -n10 (x100) git log --all
next / no-notes 4.78s 63.90s
before / no-notes 4.77s 63.61s
before / no-fanout 56.59s 65.19s
16tree / no-notes 4.73s 63.80s
16tree / no-fanout 30.21s 65.11s
16tree / 2_38 5.53s 65.24s
16tree / 2_2_36 5.15s 65.12s
concat / no-notes 4.80s 64.21s
concat / no-fanout 30.66s 65.35s
concat / 2_38 5.64s 65.87s
concat / 2_2_36 5.23s 66.44s
Conclusion: There is a small, but measurable impact (about .1s or so in
the 100 x 'git log -n10' case), but I think this is small enough to be
acceptable.
Johan Herland (17):
Teach "-m <msg>" and "-F <file>" to "git notes edit"
fast-import: Add support for importing commit notes
t3302-notes-index-expensive: Speed up create_repo()
Add flags to get_commit_notes() to control the format of the note string
Teach notes code to free its internal data structures on request
Teach the notes lookup code to parse notes trees with various fanout schemes
Add selftests verifying that we can parse notes trees with various fanouts
Refactor notes code to concatenate multiple notes annotating the same object
Add selftests verifying concatenation of multiple notes for the same commit
Notes API: get_commit_notes() -> format_note() + remove the commit restriction
Notes API: init_notes(): Initialize the notes tree from the given notes ref
Notes API: add_note(): Add note objects to the internal notes tree structure
Notes API: get_note(): Return the note annotating the given object
Notes API: for_each_note(): Traverse the entire notes tree with a callback
Notes API: Allow multiple concurrent notes trees with new struct notes_tree
Refactor notes concatenation into a flexible interface for combining notes
fast-import: Proper notes tree manipulation using the notes API
Johannes Schindelin (5):
Introduce commit notes
Add a script to edit/inspect notes
Speed up git notes lookup
Add an expensive test for git-notes
Add '%N'-format for pretty-printing commit notes
.gitignore | 1 +
Documentation/config.txt | 13 +
Documentation/git-fast-import.txt | 45 +++-
Documentation/git-notes.txt | 60 ++++
Documentation/pretty-formats.txt | 1 +
Makefile | 3 +
cache.h | 4 +
command-list.txt | 1 +
commit.c | 1 +
config.c | 5 +
environment.c | 1 +
fast-import.c | 176 +++++++++++-
git-notes.sh | 121 ++++++++
notes.c | 579 +++++++++++++++++++++++++++++++++++++
notes.h | 113 +++++++
pretty.c | 10 +
t/t3301-notes.sh | 150 ++++++++++
t/t3302-notes-index-expensive.sh | 118 ++++++++
t/t3303-notes-subtrees.sh | 188 ++++++++++++
t/t9300-fast-import.sh | 296 +++++++++++++++++++
20 files changed, 1875 insertions(+), 11 deletions(-)
create mode 100644 Documentation/git-notes.txt
create mode 100755 git-notes.sh
create mode 100644 notes.c
create mode 100644 notes.h
create mode 100755 t/t3301-notes.sh
create mode 100755 t/t3302-notes-index-expensive.sh
create mode 100755 t/t3303-notes-subtrees.sh
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