RATIONALE
---------
-Why not use something like StGIT or Guilt or rebase -i for that?
-The advantage of these tools is their simplicity; they work with patch
-_series_ and defer to the reflog facility for version control of patches
-(reordering of patches is not version-controlled at all). But there are
-several disadvantages - for one, these tools (especially StGIT) do not
-actually fit well with plain Git at all - it is basically impossible
-to take advantage of index efectively when using StGIT. But more
-importantly, these tools horribly fail in the face of distributed
-environment.
-
-TopGit has been designed around three main tenents:
+Why not use something like StGIT or Guilt or rebase -i for maintaining
+your patch queue? The advantage of these tools is their simplicity;
+they work with patch _series_ and defer to the reflog facility for
+version control of patches (reordering of patches is not
+version-controlled at all). But there are several disadvantages -
+for one, these tools (especially StGIT) do not actually fit well
+with plain Git at all: it is basically impossible to take advantage
+of the index efectively when using StGIT. But more importantly,
+these tools horribly fail in the face of distributed environment.
+
+TopGit has been designed around three main tenets:
(i) TopGit is as thin layer on top of Git as possible.
You still maintain your index and commit using Git, TopGit will
only automate few indispensable tasks.
(ii) TopGit is anxious about _keeping_ your history. It will
-never rewrite your history and all metadata are also tracked by Git,
-smoothly and non-obnoxiously. It is useful if there is a _single_
-point when the history is cleaned up, and that is at the point of
-inclusion in the upstream project; locally, you can see how your
-patch has evolved and easily return to older versions.
+never rewrite your history and all metadata is also tracked by Git,
+smoothly and non-obnoxiously. It is good to have a _single_ point
+when the history is cleaned up, and that is at the point of inclusion
+in the upstream project; locally, you can see how your patch has evolved
+and easily return to older versions.
(iii) TopGit is specifically designed to work in distributed
environment. You can have several instances of TopGit-aware repositories
simpler, conceptually. If you just want to make a linear purely-local
patch queue, deferring to StGIT instead might make more sense.
- (ii) While keeping your history anxiously, in some extreme
-cases the TopGit-generated history graph will perhaps be a little
-too complex. ;-)
+ (ii) When using TopGit, your history can get a little hairy
+over time, especially with all the merges rippling through. ;-)
SYNOPSIS
$ ..hack..
$ git commit
- ## Create another topic branch on top of specified one and submit
+ ## Create another topic branch on top of master and submit
## the resulting patch upstream
- $ tg create -d master t/revlist/author-fixed
+ $ tg create t/revlist/author-fixed master
tg: Creating t/revlist/author-fixed base from master...
$ ..hack..
$ git commit
Subject: [PATCH] Fix broken revlist --author when --fixed-string
## Create another topic branch depending on two others non-trivially
- $ tg create -d t/revlist/author-fixed,t/gitweb/nifty-links t/whatever
+ $ tg create t/whatever t/revlist/author-fixed t/gitweb/nifty-links
tg: Creating t/whatever base from t/revlist/author-fixed...
tg: Merging t/whatever base with t/gitweb/nifty-links...
Merge failed!
tg: you will want to switch to a different branch.
$ ..resolve..
$ git commit
+ $ tg create
tg: Resuming t/whatever setup...
- $ tg create t/whatever
$ ..hack..
$ git commit
~~~~~~~~~
Create a new TopGit-controlled topic branch of a given name
(required argument) and switch to it. If no dependencies
- are specified using the '-d' paremeter, the current branch
- is assumed to be the only dependency.
+ are specified (by extra arguments passed after the first one),
+ the current branch is assumed to be the only dependency.
After `tg create`, you should insert the patch description
- to the '.topmsg' file.
+ to the '.topmsg' file, which will already contain some
+ pre-filled bits. You can set topgit.to, topgit.cc and topgit.bcc
+ configuration variables in order to have `tg create`
+ add these headers with given default values to '.topmsg'.
The main task of `tg create` is to set up the topic branch
base from the dependencies. This may fail due to merge conflicts.
it will detect that you are on a topic branch base ref and
resume the topic branch creation operation.
- '-d':
- Manually specified dependencies. A comma- or
- space-separated list of branch names.
-
tg delete
~~~~~~~~~
Remove a TopGit-controlled topic branch of given name
The patch is by default simply dumped to stdout. In the future,
tg patch will be able to automatically send the patches by mail
- or save them to files.
+ or save them to files. (TODO)
TODO: tg patch -i to base at index instead of branch,
-w for working tree
+tg remote
+~~~~~~~~~
+ Register given remote as TopGit-controlled. This will create
+ the namespace for the remote branch bases and teach 'git fetch'
+ and 'git push' to operate on them.
+
+ It takes a mandatory remote name argument, and optional
+ '--populate' switch - use that for your origin-style remote,
+ it will seed the local topic branch system based on the
+ remote topic branches. '--populate' will also make 'tg remote'
+ automatically fetch the remote and 'tg update' to look at
+ branches of this remote for updates by default.
+
tg summary
~~~~~~~~~~
Show overview of all TopGit-tracked topic branches and their
up-to-date status ('0' marks that it introduces no own changes,
'D' marks that it is out-of-date wrt. its dependencies,
+ '!' marks that it has missing dependencies (even recursively),
'B' marks that it is out-of-date wrt. its base).
+ TODO: Speed up by an order of magnitude
+ TODO: Graph view
+
+tg export
+~~~~~~~~~
+ Export a tidied-up history of the current topic branch
+ and its dependencies, suitable for feeding upstream.
+ Each topic branch corresponds to a single commit or patch
+ in the cleaned up history (corresponding basically exactly
+ to `tg patch` output for the topic branch).
+
+ The command has two posible outputs now - either a Git branch
+ with the collapsed history, or a quilt series in new directory.
+
+ In case of producing collapsed history in new branch,
+ You can use this collapsed structure either for providing
+ a pull source for upstream, or further linearization e.g.
+ for creation of a quilt series using git log:
+
+ git log --pretty=email -p --topo-order origin..exported
+
+ To better understand the function of `tg export`,
+ consider this dependency structure of topic branches:
+
+ origin/master - t/foo/blue - t/foo/red - master
+ `- t/bar/good <,----------'
+ `- t/baz ------------'
+
+ (Where each of the branches may have hefty history.) Then
+
+ master$ tg export for-linus
+
+ will create this commit structure on branch for-linus:
+
+ origin/master - t/foo/blue -. merge - t/foo/red -.. merge - master
+ `- t/bar/good <,-------------------'/
+ `- t/baz ---------------------'
+
+ In case of the quilt mode,
+
+ master$ tg export --quilt for-linus
+
+ would create this directory for-linus:
+
+ for-linus/t/foo/blue.diff
+ for-linus/t/foo/red.diff
+ for-linus/t/bar/good.diff
+ for-linus/t/baz.diff
+ for-linus/series:
+ t/foo/blue.diff -p1
+ t/bar/good.diff -p1
+ t/foo/red.diff -p1
+ t/baz.diff -p1
+
+ The command works on the current topic branch
+ and can be called either without a parameter
+ (in that case, '--collapse' is assumed)
+ and with one mandatory argument: the name of the branch
+ where the exported result shall be stored.
+ The branch will be silently overwritten if it exists already!
+ Use git reflog to recover in case of mistake.
+
+ Alternatively, call it with the '--quilt' parameter
+ and an argument specifying the directory
+ where the quilt series should be saved.
+
+ Usage: tg export ([--collapse] BRANCH | --quilt DIR)
+
+ TODO: Make stripping of non-essential headers configurable
+ TODO: Make stripping of [PATCH] and other prefixes configurable
+ TODO: --mbox option for other mode of operation
+ TODO: -n option to prevent exporting of empty patches
+ TODO: -a option to export all branches
+ TODO: Allow branches to be exported to be passed as arguments, default
+ to the current branch if none are specified
+ TODO: For quilt exporting, use a temporary branch and remove it when
+ done - this would allow producing conflict-less series
+
tg update
~~~~~~~~~
Update the current topic branch wrt. changes in the branches
- it depends on. This is made in two phases - first,
+ it depends on and remote branches.
+ This is performed in two phases - first,
changes within the dependencies are merged to the base,
- then the base is merged into the topic branch. The output
- will guide you in case of conflicts.
+ then the base is merged into the topic branch.
+ The output will guide you in case of conflicts.
In case your dependencies are not up-to-date, tg update
will first recurse into them and update these.
TODO: Some infrastructure for sharing topic branches between
repositories easily
+TODO: tg depend for adding/removing dependencies smoothly
+TODO: tg rename
IMPLEMENTATION
Thus, as your patches evolve, you can record nuances like whether
the paricular patch should have To-list/Cc-maintainer or vice
versa and similar nuances, if your project is into that.
+From is prefilled from your current GIT_AUTHOR_IDENT, other headers
+can be prefilled from various optional topgit.* config options.
.topdeps: Contains the one-per-line list of branches
your patch depends on, pre-seeded with `tg create`. (Continuously
Another automagically installed piece is .git/info/attributes specifier
for an 'ours' merge strategy for the files .topmsg and .topdeps, and
the (intuitive) 'ours' merge strategy definition in .git/config.
+
+
+REMOTE HANDLING
+---------------
+
+There are three issues with accessing topic branches in remote repositories:
+
+ (i) Fetching/pushing accurate picture of the remote topic branch setup
+ (ii) Referring to remote topic branches from your local repository
+ (iii) Developing some of the remote topic branches locally
+
+(ii) and (iii) are fairly interconnected problems, while (i) is largely
+independent. The issue is to accurately reflect the current state of the
+quickly changing topic branches set - this can be easily done
+with the current facilities like 'git remote prune' and 'git push --mirror' -
+and to properly upload also the bases of the topic branches.
+For this, we need to modify the fetch/push refspecs to also include
+the refs/top-bases/ ref namespace; we shall provide a special 'tg remote'
+command to set up an existing remote for TopGit usage.
+
+About (ii) and (iii), there are two somewhat contradicting design
+considerations:
+
+ (a) Hacking on multiple independent TopGit remotes in a single
+ repository
+ (b) Having a self-contained topic system in local refs space
+
+To us, (a) does not appear to be very convincing, while (b) is quite desirable
+for 'git-log topic' etc. working, 'git push' automatically creating
+self-contained topic system in the remote repository, and increased conceptual
+simplicity.
+
+Thus, we choose to instantiate all the topic branches of given remote locally;
+this is performed by 'tg remote --populate'.
+'tg update' will also check if a branch can be updated from its corresponding
+remote branch. The logic is somewhat involved if we should DTRT.
+First, we update the base, handling the remote branch as if it was the first
+dependency; thus, conflict resolutions made in the remote branch will be
+carried over to our local base automagically. Then, the base is merged into
+remote branch and the result is merged to local branch - again, to carry over
+remote conflict resolutions. In the future, this order might be adjustable
+per-update in case local changes are diverging more than the remote ones.
~ian / topgit.git / blobdiff