Gerrit » History » Version 65
neels, 04/25/2017 11:38 AM
1 | 1 | zecke | h1. Contributing using Gerrit |
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2 | |||
3 | 11 | laforge | {{>toc}} |
4 | |||
5 | 10 | laforge | At [[OpenBSC:OsmoDevCon2016]] we discussed problems with our past contribution / patch submission process using mails on the mailing list as well as patchwork. The result is that we want to give Gerrit a try for some time and see if it helps us to have a better process |
6 | 1 | zecke | |
7 | 10 | laforge | Gerrit is a review tool that integrates nicely with git and ssh. You can find general information about Gerrit at https://www.gerritcodereview.com/ |
8 | 1 | zecke | |
9 | 10 | laforge | The advantages of Gerrit are: |
10 | * patch submission status is automatically tracked, also with several revisions for a patch set. |
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11 | * patches are build-tested (and possibly even further tested) by jenkins before they are applied |
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12 | * developers + maintainers can formally vote on a patch (developer: -1/0/+1, maintainer: -2/0/+2) |
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13 | * once a patch has +2 score, it can be (automatically) merged into master |
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14 | * patch sumissions not via git send-email but direcly from git |
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15 | |||
16 | h2. Osmocom Subprojects using Gerrit |
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17 | |||
18 | 1 | zecke | The following projects use Gerrit to contribute changes: |
19 | |||
20 | * libosmocore.git |
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21 | * libosmo-abis.git |
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22 | * libosmo-netif.git |
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23 | * libosmo-sccp.git |
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24 | * libsmpp34.git |
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25 | * openbsc.git |
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26 | * osmo-bts.git |
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27 | * osmo-iuh.git |
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28 | * osmo-pcu.git |
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29 | 5 | zecke | * cellmgr-ng.git |
30 | 1 | zecke | * osmo-sip-connector.git |
31 | 30 | neels | |
32 | 1 | zecke | h2. Configuring Gerrit/Account |
33 | |||
34 | 54 | neels | You will need to sign-up at https://gerrit.osmocom.org/login/. If you have an Osmocom Redmine account you can use https://osmocom.org/openid as OpenID provider. |
35 | 1 | zecke | |
36 | 55 | neels | * first sign in on https://osmocom.org. |
37 | * go to https://gerrit.osmocom.org and click the "Sign in" link. |
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38 | 61 | neels | * enter <pre>https://osmocom.org/openid</pre> as OpenID provider and hit the "Sign in" button. |
39 | |||
40 | *careful:* enter 'https' to ensure that your openid credentials are passed on encryptedly. |
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41 | *pitfall:* if you're logged in on 'projects.osmocom.org', you should also use the openid provider: <pre>https://projects.osmocom.org/openid</pre> |
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42 | *note:* gerrit will create a distinct user for each openid URL you pass. If you logged in successfully but your user seems to have lost permissions, you may have created an evil twin user: contact us on the mailing list so we can fix it in the user database. |
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43 | 54 | neels | |
44 | If you have no Osmocom redmine account, you can simply create one online at the "Register" link in the upper right corner. |
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45 | 10 | laforge | Even without an existing or new redmine account, you should also be able to use any other OpenID provider to authenticate against gerrit (untested). |
46 | |||
47 | After the initial sign-up you will need to: |
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48 | 1 | zecke | |
49 | * Pick a username (can not be changed) |
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50 | * Add your public ssh key(s) |
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51 | * Add email addresses you intend to use as author/comitter |
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52 | 30 | neels | |
53 | If you would like to push private branches to the Gerrit repository, you also need to be added to the "known users" group. |
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54 | Please send a short requesting email to openbsc@lists.osmocom.org. |
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55 | 1 | zecke | |
56 | h2. Setting up Gerrit for commits and pushing |
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57 | |||
58 | 33 | neels | *Note:* it is easiest to work with gerrit when gerrit is the only remote in your git clone. |
59 | When you clone from git.osmocom.org and add the gerrit remote, git will have two remotes, |
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60 | 36 | neels | so when you first checkout a branch you have to supply the remote explicitly (cumbersome). |
61 | 34 | neels | The gerrit repositories and git.osmocom.org are constantly synced, so it is sufficient |
62 | to clone from gerrit only. |
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63 | 33 | neels | |
64 | h3. Simplest: new clone |
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65 | |||
66 | 35 | neels | * Create a new clone from gerrit |
67 | * Fetch the commit hook that adds Change-Id to each commit to uniquely identify a commit |
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68 | 42 | neels | |
69 | 33 | neels | <pre> |
70 | git clone ssh://$USERNAME@gerrit.osmocom.org:29418/$PROJECT.git |
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71 | scp -P 29418 $USERNAME@gerrit.osmocom.org:hooks/commit-msg $PROJECT/.git/hooks/ |
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72 | </pre> |
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73 | |||
74 | h3. SSH config |
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75 | |||
76 | In '~/.ssh/config', add these lines: |
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77 | <pre> |
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78 | 52 | neels | Host go |
79 | 33 | neels | Hostname gerrit.osmocom.org |
80 | Port 29418 |
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81 | User $USERNAME |
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82 | </pre> |
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83 | 52 | neels | ('go' means gerrit.osmocom, replace with your favorite shortcut name, |
84 | 33 | neels | replace '$USERNAME' with your user name as used on the gerrit website) |
85 | |||
86 | Then you can shorten above commands to |
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87 | 1 | zecke | <pre> |
88 | 52 | neels | git clone ssh://go/$PROJECT.git |
89 | 51 | neels | cd $PROJECT |
90 | scp go:hooks/commit-msg .git/hooks/ |
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91 | 33 | neels | </pre> |
92 | |||
93 | 46 | neels | h3. Committer must match |
94 | |||
95 | 47 | neels | Your email address on gerrit and the email address git places in your |
96 | 46 | neels | commits must match, or you will get rejected with an error message like |
97 | "invalid commiter". You can add email addresses on the gerrit web UI. |
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98 | |||
99 | 33 | neels | h3. Add gerrit to an existing clone |
100 | |||
101 | 7 | neels | * Add the remote to be able to fetch and push to gerrit |
102 | * Fetch the commit hook that adds Change-Id to each commit to uniquely identify a commit |
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103 | |||
104 | <pre> |
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105 | USERNAME=gerrit_user_name |
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106 | PROJECT=$(basename $PWD) |
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107 | 1 | zecke | git remote add gerrit ssh://$USERNAME@gerrit.osmocom.org:29418/$PROJECT.git |
108 | scp -P 29418 $USERNAME@gerrit.osmocom.org:hooks/commit-msg .git/hooks/ |
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109 | 44 | neels | </pre> |
110 | |||
111 | 33 | neels | h2. Push for review |
112 | 1 | zecke | |
113 | 38 | neels | Checkout the revision or branch that you want to submit for review, then |
114 | |||
115 | 31 | neels | <pre> |
116 | 48 | ahuemer | git push gerrit HEAD:refs/for/master |
117 | 1 | zecke | </pre> |
118 | 38 | neels | |
119 | 1 | zecke | You can optionally add a topic name with |
120 | 40 | neels | |
121 | <pre> |
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122 | 48 | ahuemer | git push gerrit HEAD:refs/for/master/my_topic |
123 | 38 | neels | </pre> |
124 | |||
125 | 57 | neels | h2. Merge patch to master |
126 | |||
127 | A patch can be merged when it has CR+2 and V+1 votes, and if, in case of a |
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128 | series of patches pushed from a branch, when its ancestor patches can also be |
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129 | merged. |
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130 | |||
131 | Sometimes the reviewer that gives CR+2 also hits the "Submit" button right away |
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132 | to merge the patch to master. Sometimes it is left up to the owner of the patch |
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133 | 59 | neels | to decide when to hit "Submit" (who needs to be in the "Known Users" group). |
134 | 57 | neels | |
135 | The V+1 vote means "build is verified" and is usually given by our jenkins |
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136 | 59 | neels | gerrit builds: https://jenkins.osmocom.org/jenkins/view/Jenkins-Gerrit/ |
137 | 57 | neels | |
138 | The CR+2 vote means "code reviewed and ready for merge to master branch". |
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139 | Accounts with the "Reviewer" role for a given project are allowed to give CR+2 |
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140 | votes. Others are allowed to give CR+1 (and CR-1). CR votes _don't_ add up. |
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141 | |||
142 | 65 | neels | _Fixed:_ -Sometimes hitting the "Submit" button results in an error message saying |
143 | 57 | neels | "Change is New", which is a bug related to a private branch with the same |
144 | 65 | neels | patches being present. Can be fixed e.g. by an admin's manual push to master.- |
145 | 1 | zecke | |
146 | 38 | neels | h2. Push a "private" user branch |
147 | 33 | neels | |
148 | 1 | zecke | *Note* that you must be a member of the "known users" group, see above. |
149 | 33 | neels | |
150 | 43 | neels | If your local branch name is of the form 'your_name/topic', you can just |
151 | 1 | zecke | <pre> |
152 | git push |
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153 | 33 | neels | </pre> |
154 | 41 | neels | and git will tell you what to do. |
155 | 1 | zecke | |
156 | 41 | neels | To push from a "nonstandard" local branch name, do |
157 | <pre> |
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158 | 50 | msuraev | git push gerrit HEAD:refs/heads/user/$USERNAME/branch_name |
159 | 33 | neels | </pre> |
160 | |||
161 | 39 | neels | |
162 | h2. List changesets in gerrit |
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163 | |||
164 | 7 | neels | <pre> |
165 | 48 | ahuemer | git ls-remote gerrit changes/* |
166 | 2 | zecke | </pre> |
167 | 12 | msuraev | |
168 | 17 | neels | h1. Tips and Tricks |
169 | 1 | zecke | |
170 | 17 | neels | h2. Throw-away branch |
171 | |||
172 | If you need to adjust and re-submit patches, it may be handy to create a throw-away branch ("R D" in magit-gerrit in emacs for example), |
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173 | 45 | neels | make your changes/amendments and then send patch(es) back to gerrit while removing temporary branch automatically with "git review -f". |
174 | 13 | neels | |
175 | 56 | neels | h2. Fetch a patch from gerrit |
176 | |||
177 | This script (I called it @P@) makes fetching a patch set from gerrit a breeze: |
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178 | <pre> |
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179 | #!/bin/sh |
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180 | # fetch gerrit patch into new branch named like the patch number. |
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181 | # |
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182 | # Usage: go to a git clone and pass a patch number: |
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183 | # |
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184 | # cd openbsc |
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185 | # P 973 |
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186 | # or |
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187 | # P 973/2 |
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188 | # |
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189 | # Will create new local branches '973_4' (if 4 is the latest patch set) |
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190 | # or '973_2', respectively. |
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191 | |||
192 | patch="$1" |
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193 | |||
194 | if [ -z "$patch" ]; then |
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195 | echo "Usage: P 1234[/5]" |
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196 | exit 1 |
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197 | fi |
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198 | |||
199 | if [ -z "$(echo "$patch" | grep '/')" ]; then |
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200 | patch="/$patch/" |
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201 | fi |
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202 | |||
203 | if [ -z "$(echo "$patch" | grep '^/')" ]; then |
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204 | patch="/$patch" |
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205 | fi |
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206 | |||
207 | last_set="$(git ls-remote origin "changes/*" | grep "$patch" | sed 's#.*/\([^/]*\)$#\1 &#' | sort -n | tail -n 1)" |
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208 | if [ -z "$last_set" ]; then |
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209 | echo "Not found: $patch" |
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210 | exit 1 |
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211 | fi |
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212 | |||
213 | change_name="$(echo "$last_set" | sed 's/.*\(refs.*\)/\1/')" |
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214 | branch_name="$(echo "$change_name" | sed 's#refs/changes/../\([0-9]*\)/\([0-9]*\)#\1_\2#')" |
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215 | |||
216 | set -x |
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217 | git fetch origin "$change_name" |
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218 | git co -b "$branch_name" FETCH_HEAD |
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219 | </pre> |
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220 | |||
221 | 25 | neels | h2. Re-submit a Branch with Amended Commits |
222 | 13 | neels | |
223 | 1 | zecke | On a feature branch, one typically has numerous commits that depend on their preceding commits. |
224 | 58 | neels | Often, some of the branch commits need to be amended for fixes. You can re-submit changes to |
225 | patches on your branch by pushing in the same way that you first submitted the branch. |
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226 | 22 | neels | |
227 | 58 | neels | Note: if you modify the Change-Ids in the commit logs, your push would open entirely new |
228 | review entries and you would have to abandon your previous submission. Comments on the first |
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229 | submission are "lost" and you cannot diff between patch sets. |
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230 | 29 | neels | |
231 | 58 | neels | (There used to be a bug in gerrit that required editing the first patch to be able to |
232 | re-submit a branch, but that's fixed.) |
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233 | 29 | neels | |
234 | |||
235 | |||
236 | 26 | neels | h2. Re-submit Previously Abandoned Changes |
237 | 16 | neels | |
238 | You have to edit the Change-Ids, on a branch that would be every single commit log message. |
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239 | |||
240 | 13 | neels | <pre> |
241 | 1 | zecke | cd openbsc |
242 | git co my-branch |
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243 | git rebase -i master |
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244 | # replace all 'pick' with 'r' (or 'reword'), exit your editor |
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245 | 13 | neels | # git presents each commit log message for editing |
246 | </pre> |
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247 | |||
248 | 27 | neels | h2. Submit a "private" branch for master |
249 | 21 | neels | |
250 | If you've pushed a branch to refs/heads/* somewhere, gerrit will already know the Change-Ids on it. |
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251 | 24 | neels | Make sure the option [[Gerrit#Private-Branches-Create-a-new-change-for-every-commit|Create a new change for every commit not in the target branch]] is _TRUE_ for your project, |
252 | 21 | neels | or gerrit will refuse to accept your submission. |
253 | |||
254 | 60 | neels | h2. 502 Bad Gateway |
255 | |||
256 | When getting a "Bad Gateway" error message upon trying to login on gerrit, you probably just need to restart your web browser. The reason is not clear. |
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257 | |||
258 | 16 | neels | h1. Reasons for Particular Configuration |
259 | 13 | neels | |
260 | 16 | neels | h2. Rebase if necessary |
261 | |||
262 | There are different merge strategies that Gerrit performs to accept patches. |
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263 | 13 | neels | Each project can be configured to a specific merge strategy, but unfortunately you can't |
264 | decide on a strategy per patch submission. |
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265 | |||
266 | It seems that the "Merge if Necessary" strategy is best supported, but it creates non-linear |
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267 | history with numerous merge commits that are usually not at all necessary. |
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268 | |||
269 | Instead, the "Cherry Pick" strategy puts each patch onto current master's HEAD to create |
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270 | linear history. However, this will cause merge failures as soon as one patch depends on |
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271 | another submitted patch, as typical for a feature branch submission. |
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272 | |||
273 | 1 | zecke | So we prefer the "Rebase if Necessary" strategy, which always tries to apply your patches to |
274 | 13 | neels | the current master HEAD, in sequence with the previous patches on the same branch. |
275 | However, some problems still remain, including some bugs in "Rebase if Necessary". |
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276 | 1 | zecke | |
277 | 13 | neels | There's a problem with "Rebase if Necessary": If your branch sits at master's HEAD, Gerrit |
278 | refuses to accept the submission, because it thinks that no new changes are submitted. |
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279 | This is a bug in Gerrit, which holger has fixed manually in our Gerrit installation: |
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280 | 1 | zecke | |
281 | https://bugs.chromium.org/p/gerrit/issues/detail?id=4158 |
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282 | |||
283 | |||
284 | 16 | neels | h2. Private Branches: Create a new change for every commit... |
285 | 1 | zecke | |
286 | 13 | neels | Say you have an extensive feature in development, and you want to keep it on the |
287 | upstream git repository to a) keep it safe and b) collaborate with other devs on it. |
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288 | 16 | neels | So, of course, you have regularly pushed to refs/heads/yoyodyne/feature. |
289 | 13 | neels | |
290 | Since you have the gerrit commit hook installed, your feature branch already has |
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291 | Change-Id tags in all commit log messages. |
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292 | |||
293 | Now your feature is complete and you would like to submit it to master. |
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294 | Alas, Gerrit refuses to accept your patch submission for master, because it |
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295 | knows the Change-Ids are also on a different branch. |
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296 | |||
297 | 16 | neels | Gerrit by default enforces that a Change-Id must be unique across all branches, |
298 | so that each submission for review is separate for each branch. Instead, we |
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299 | want to handle Change-Ids per-branch, so that you can have the same change |
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300 | submitted to different branches, as separate patch submissions, without having |
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301 | to cosmetically adjust the Change-Id. |
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302 | 13 | neels | |
303 | 16 | neels | Solution: set the option |
304 | _Create a new change for every commit not in the target branch_ to _TRUE_ |
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305 | 13 | neels | |
306 | 20 | neels | h2. Allow content merges |
307 | 14 | neels | |
308 | By default, gerrit compares patches only by the files' paths. If two paths are the same, |
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309 | it immediately shows them as conflicts (path conflicts). |
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310 | |||
311 | In software development, a conflict usually means an actual content conflict, so if the |
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312 | edits are in two entirely separate places in the file, we don't consider this a conflict. |
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313 | |||
314 | 23 | neels | By setting _Allow content merges_ to _TRUE_ in the git project config, we tell Gerrit to |
315 | 14 | neels | perform text merges of the submitted patches and only complain about actual content |
316 | conflicts, in the usual software engineering sense. |
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317 | 32 | neels | |
318 | h1. Admin |
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319 | |||
320 | h2. Adding users to groups |
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321 | |||
322 | Normally, the gerrit UI auto-completes a user name in the edit field. It has happened |
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323 | though that an existing user is not auto-completed, as if it didn't exist. In that case, |
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324 | find out the user ID (seven digit number like 1000123) and just enter that. |
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325 | |||
326 | The user ID can be found on the user's "Settings" page, or in the database (s.b.). |
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327 | |||
328 | h2. Querying the database directly |
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329 | |||
330 | If your user has permission to access the database, you can place SQL queries using the |
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331 | 'gerrit gsql' commands over ssh: |
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332 | |||
333 | <pre> |
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334 | 64 | neels | ssh go 'gerrit gsql -c "show tables"' |
335 | ssh go 'gerrit gsql -c "select full_name,account_id from accounts"' |
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336 | 1 | zecke | </pre> |
337 | 53 | neels | |
338 | (see ~/.ssh/config above for the 'go' shortcut) |
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339 | 32 | neels | |
340 | This seems to be the MySQL dialect. |
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341 | 62 | neels | |
342 | h2. Fix evil twin users |
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343 | |||
344 | If differing openid URLs have lead to evil twin users shadowing the same email address just without the permissions, you can fix it like this: |
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345 | |||
346 | <pre> |
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347 | 64 | neels | ssh go "gerrit gsql -c \"select * from account_external_ids where email_address like '%foo%'\"" |
348 | 62 | neels | # ACCOUNT_ID | EMAIL_ADDRESS | PASSWORD | EXTERNAL_ID |
349 | # -----------+-----------------+----------+---------------------------------- |
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350 | # 100004 | foo@example.com | NULL | https://osmocom.org/openid/user/777 |
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351 | # 100021 | foo@example.com | NULL | https://projects.osmocom.org/openid/user/777 |
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352 | |||
353 | 64 | neels | ssh go "gerrit gsql -c \"update account_external_ids set account_id = 100004 where email_address like '%foo%'\"" |
354 | 62 | neels | |
355 | 64 | neels | ssh go "gerrit gsql -c \"select * from account_external_ids where email_address like '%foo%'\"" |
356 | 62 | neels | # ACCOUNT_ID | EMAIL_ADDRESS | PASSWORD | EXTERNAL_ID |
357 | # -----------+-----------------+----------+---------------------------------- |
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358 | # 100004 | foo@example.com | NULL | https://osmocom.org/openid/user/777 |
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359 | # 100004 | foo@example.com | NULL | https://projects.osmocom.org/openid/user/777 |
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360 | </pre> |