1 TopGit - A different patch queue manager
7 TopGit aims to make handling of large amount of interdependent topic
8 branches easier. In fact, it is designed especially for the case
9 when you maintain a queue of third-party patches on top of another
10 (perhaps Git-controlled) project and want to easily organize, maintain
11 and submit them - TopGit achieves that by keeping a separate topic
12 branch for each patch and providing few tools to maintain the branches.
18 Why not use something like StGIT or Guilt or rebase -i for maintaining
19 your patch queue? The advantage of these tools is their simplicity;
20 they work with patch _series_ and defer to the reflog facility for
21 version control of patches (reordering of patches is not
22 version-controlled at all). But there are several disadvantages -
23 for one, these tools (especially StGIT) do not actually fit well
24 with plain Git at all: it is basically impossible to take advantage
25 of the index efectively when using StGIT. But more importantly,
26 these tools horribly fail in the face of distributed environment.
28 TopGit has been designed around three main tenets:
30 (i) TopGit is as thin layer on top of Git as possible.
31 You still maintain your index and commit using Git, TopGit will
32 only automate few indispensable tasks.
34 (ii) TopGit is anxious about _keeping_ your history. It will
35 never rewrite your history and all metadata is also tracked by Git,
36 smoothly and non-obnoxiously. It is good to have a _single_ point
37 when the history is cleaned up, and that is at the point of inclusion
38 in the upstream project; locally, you can see how your patch has evolved
39 and easily return to older versions.
41 (iii) TopGit is specifically designed to work in distributed
42 environment. You can have several instances of TopGit-aware repositories
43 and smoothly keep them all up-to-date and transfer your changes between
46 As mentioned above, the main intended use-case for TopGit is tracking
47 third-party patches, where each patch is effectively a single topic
48 branch. In order to flexibly accomodate even complex scenarios when
49 you track many patches where many are independent but some depend
50 on others, TopGit ignores the ancient Quilt heritage of patch series
51 and instead allows the patches to freely form graphs (DAGs just like
52 Git history itself, only "one lever higher"). For now, you have
53 to manually specify which patches does the current one depend
54 on, but TopGit might help you with that in the future in a darcs-like
57 A glossary plug: The union (i.e. merge) of patch dependencies is
58 called a _base_ of the patch (topic branch).
60 Of course, TopGit is perhaps not the right tool for you:
62 (i) TopGit is not complicated, but StGIT et al. are somewhat
63 simpler, conceptually. If you just want to make a linear purely-local
64 patch queue, deferring to StGIT instead might make more sense.
66 (ii) When using TopGit, your history can get a little hairy
67 over time, especially with all the merges rippling through. ;-)
73 ## Create and evolve a topic branch
74 $ tg create t/gitweb/pathinfo-action
75 tg: Automatically marking dependency on master
76 tg: Creating t/gitweb/pathinfo-action base from master...
82 ## Create another topic branch on top of the former one
83 $ tg create t/gitweb/nifty-links
84 tg: Automatically marking dependency on t/gitweb/pathinfo-action
85 tg: Creating t/gitweb/nifty-links base from t/gitweb/pathinfo-action...
89 ## Create another topic branch on top of master and submit
90 ## the resulting patch upstream
91 $ tg create t/revlist/author-fixed master
92 tg: Creating t/revlist/author-fixed base from master...
96 tg: Sent t/revlist/author-fixed
98 To: git@vger.kernel.org
100 Subject: [PATCH] Fix broken revlist --author when --fixed-string
102 ## Create another topic branch depending on two others non-trivially
103 $ tg create t/whatever t/revlist/author-fixed t/gitweb/nifty-links
104 tg: Creating t/whatever base from t/revlist/author-fixed...
105 tg: Merging t/whatever base with t/gitweb/nifty-links...
107 tg: Please commit merge resolution and call: tg create
108 tg: It is also safe to abort this operation using `git reset --hard`
109 tg: but please remember you are on the base branch now;
110 tg: you will want to switch to a different branch.
114 tg: Resuming t/whatever setup...
118 ## Update a single topic branch and propagate the changes to
120 $ git checkout t/gitweb/nifty-links
123 $ git checkout t/whatever
125 Topic Branch: t/whatever (1 commit)
126 Subject: [PATCH] Whatever patch
128 Depends: t/revlist/author-fixed t/gitweb/nifty-links
130 t/gitweb/nifty-links (1 commit)
132 tg: Updating base with t/gitweb/nifty-links changes...
134 tg: Please commit merge resolution and call `tg update` again.
135 tg: It is also safe to abort this operation using `git reset --hard`,
136 tg: but please remember you are on the base branch now;
137 tg: you will want to switch to a different branch.
141 tg: Updating t/whatever against new base...
143 tg: Please resolve the merge and commit. No need to do anything else.
144 tg: You can abort this operation using `git reset --hard` now
145 tg: and retry this merge later using `tg update`.
149 ## Update a single topic branch and propagate the changes
150 ## further through the dependency chain
151 $ git checkout t/gitweb/pathinfo-action
154 $ git checkout t/whatever
156 Topic Branch: t/whatever (1/2 commits)
157 Subject: [PATCH] Whatever patch
159 Depends: t/revlist/author-fixed t/gitweb/nifty-links
161 t/gitweb/pathinfo-action (<= t/gitweb/nifty-links) (1 commit)
163 tg: Recursing to t/gitweb/nifty-links...
164 [t/gitweb/nifty-links] tg: Updating base with t/gitweb/pathinfo-action changes...
166 [t/gitweb/nifty-links] tg: Please commit merge resolution and call `tg update` again.
167 [t/gitweb/nifty-links] tg: It is also safe to abort this operation using `git reset --hard`,
168 [t/gitweb/nifty-links] tg: but please remember you are on the base branch now;
169 [t/gitweb/nifty-links] tg: you will want to switch to a different branch.
170 [t/gitweb/nifty-links] tg: You are in a subshell. If you abort the merge,
171 [t/gitweb/nifty-links] tg: use `exit` to abort the recursive update altogether.
172 [t/gitweb/nifty-links] $ ..resolve..
173 [t/gitweb/nifty-links] $ git commit
174 [t/gitweb/nifty-links] $ tg update
175 [t/gitweb/nifty-links] tg: Updating t/gitweb/nifty-links against new base...
177 [t/gitweb/nifty-links] tg: Please resolve the merge and commit.
178 [t/gitweb/nifty-links] tg: You can abort this operation using `git reset --hard`.
179 [t/gitweb/nifty-links] tg: You are in a subshell. After you either commit or abort
180 [t/gitweb/nifty-links] tg: your merge, use `exit` to proceed with the recursive update.
181 [t/gitweb/nifty-links] $ ..resolve..
182 [t/gitweb/nifty-links] $ git commit
183 [t/gitweb/nifty-links] $ exit
184 tg: Updating base with t/gitweb/nifty-links changes...
185 tg: Updating t/whatever against new base...
191 The 'tg' tool of TopGit has several subcommands:
195 Our sophisticated integrated help facility. Doesn't do
200 Create a new TopGit-controlled topic branch of a given name
201 (required argument) and switch to it. If no dependencies
202 are specified (by extra arguments passed after the first one),
203 the current branch is assumed to be the only dependency.
205 After `tg create`, you should insert the patch description
206 to the '.topmsg' file.
208 The main task of `tg create` is to set up the topic branch
209 base from the dependencies. This may fail due to merge conflicts.
210 In that case, after you commit the conflicts resolution,
211 you should call `tg create` again (without any arguments);
212 it will detect that you are on a topic branch base ref and
213 resume the topic branch creation operation.
217 Remove a TopGit-controlled topic branch of given name
218 (required argument). Normally, this command will remove
219 only empty branch (base == head); use '-f' to remove
222 Currently, this command will _NOT_ remove the branch from
223 the dependency list in other branches. You need to take
224 care of this _manually_. This is even more complicated
225 in combination with '-f', in that case you need to manually
226 unmerge the removed branch's changes from the branches
229 TODO: '-a' to delete all empty branches, depfix, revert
233 Show a summary information about the current or specified
238 Generate a patch from the current or specified topic branch.
239 This means that the diff between the topic branch base and
240 head (latest commit) is shown, appended to the description
241 found in the .topmsg file.
243 The patch is by default simply dumped to stdout. In the future,
244 tg patch will be able to automatically send the patches by mail
245 or save them to files. (TODO)
247 TODO: tg patch -i to base at index instead of branch,
252 Show overview of all TopGit-tracked topic branches and their
253 up-to-date status ('0' marks that it introduces no own changes,
254 'D' marks that it is out-of-date wrt. its dependencies,
255 '!' marks that it has missing dependencies (even recursively),
256 'B' marks that it is out-of-date wrt. its base).
258 TODO: Speed up by an order of magnitude
263 Update the current topic branch wrt. changes in the branches
264 it depends on. This is made in two phases - first,
265 changes within the dependencies are merged to the base,
266 then the base is merged into the topic branch. The output
267 will guide you in case of conflicts.
269 In case your dependencies are not up-to-date, tg update
270 will first recurse into them and update these.
272 TODO: tg update -a for updating all topic branches
274 TODO: Some infrastructure for sharing topic branches between
276 TODO: tg depend for adding/removing dependencies smoothly
277 TODO: tg collapse for creating a one-commit-per-patch tidied up
278 history (for pulling by upstream)
284 TopGit stores all the topic branches in the regular refs/heads/
285 namespace, (we recommend to mark them with the 't/' prefix).
286 Except that, TopGit also maintains a set of auxiliary refs in
287 refs/top-*. Currently, only refs/top-bases/ is used, containing
288 the current _base_ of the given topic branch - this is basically
289 a merge of all the branches the topic branch depends on; it is
290 updated during `tg update` and then merged to the topic branch,
291 and it is the base of a patch generated from the topic branch by
294 All the metadata is tracked within the source tree and history
295 of the topic branch itself, in .top* files; these files are kept
296 isolated within the topic branches during TopGit-controlled merges
297 and are of course omitted during `tg patch`. The state of these
298 files in base commits is undefined; look at them only in the topic
299 branches themselves. Currently, two files are defined:
301 .topmsg: Contains the description of the topic branch
302 in a mail-like format, plus the author information,
303 whatever Cc headers you choose or the post-three-dashes message.
304 When mailing out your patch, basically only few extra headers
305 mail headers are inserted and the patch itself is appended.
306 Thus, as your patches evolve, you can record nuances like whether
307 the paricular patch should have To-list/Cc-maintainer or vice
308 versa and similar nuances, if your project is into that.
310 .topdeps: Contains the one-per-line list of branches
311 your patch depends on, pre-seeded with `tg create`. (Continuously
312 updated) merge of these branches will be the "base" of your topic
315 TopGit also automagically installs a bunch of custom commit-related
316 hooks that will verify if you are committing the .top* files in sane
317 state. It will add the hooks to separate files within the hooks/
318 subdirectory and merely insert calls of them to the appropriate hooks
319 and make them executable (but make sure the original hooks code
320 is not called if the hook was not executable beforehand).
322 Another automagically installed piece is .git/info/attributes specifier
323 for an 'ours' merge strategy for the files .topmsg and .topdeps, and
324 the (intuitive) 'ours' merge strategy definition in .git/config.