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7 <title>Access To The GHC CVS Repository</title>
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12 <h1><b>FP Tools CVS Cheat Sheet</b></h1>
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14 <p>We use CVS (Concurrent Version System) to keep track of our sources for various
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15 software projects. CVS lets several people work on the same software at the same time,
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16 allowing changes to be checked in incrementally. </p>
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18 <p>Information on using CVS can be obtained from <a HREF="http://www.cyclic.com">Cyclic
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21 <p>This note is supposed to be a set of guidelines for how to use our CVS repository, and
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22 will probably evolve in time. The main thing to remember is that most mistakes can be
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23 undone, but if there's anything you're not sure about feel free to bug the local CVS
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24 meister (namely <a HREF="mailto:jlewis@cse.ogi.edu">Jeff Lewis</a>). </p>
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29 <li><a HREF="#read-only">Read-only remote access</a></li>
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30 <li><a HREF="#read-write">Read-write remote access</a></li>
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31 <li><a HREF="#first">Using CVS for the first time</a></li>
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32 <li><a HREF="#checkout">Checking out a source tree</a></li>
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33 <li><a HREF="#commit">Committing changes</a></li>
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34 <li><a HREF="#update">Updating your source tree</a></li>
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35 <li><a HREF="#hints">General Hints</a></li>
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38 <h2><a NAME="read-only"></a><b>Remote Read-only CVS Access</b></h2>
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40 <p>Read-only access is available to anyone - there's no need to ask us first. To get
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41 read-only access to our repository:
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44 <li>set your CVSROOT environment variable to <tt>:pserver:anoncvs@glass.cse.ogi.edu:/cvs</tt></li>
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45 <li>The first time you access the repository, you'll need to do <tt>cvs login</tt>.
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46 The password is simply <tt>cvs</tt>. This sets up a file in your home directory
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47 called <tt>.cvspass</tt>, which squirrels away the dummy password, so you only need to do
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48 this step one time.</li>
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49 <li>Now, you can check out a source tree using normal CVS commands. For example:</li>
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50 <pre> $ cvs checkout fpconfig
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51 $ cd fptools
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52 $ cvs checkout ghc</pre>
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53 <p>gets a brand spanking new set of GHC sources.</p>
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56 <p>The layout of our CVS repository is described below, under <a HREF="#first">Using CVS
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57 for the first time</a>. </p>
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59 <p>With read-only CVS access you can do anything except commit changes to the repository.
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60 You can make changes to your local tree, and still use CVS's merge facility to keep your
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61 tree up to date, and you can generate patches using 'cvs diff' in order to send to us for
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64 <h2><a NAME="read-write"></a><b>Remote Read-Write CVS Access</b></h2>
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66 <p>We generally supply read-write access to folk doing serious development on some part of
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67 the source tree, when going through us would be a pain. If you're developing some feature,
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68 or think you have the time and inclination to fix bugs in our sources, feel free to ask
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69 for read-write access. There is a certain amount of responsibility that goes with commit
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70 privileges; we are more likely to grant you access if you've demonstrated your competence
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71 by sending us patches via mail in the past. </p>
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73 <p>To use remote CVS, you need to supply me with a username and
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74 encrypted password. Once you've done that and the account on
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75 cvs.haskell.org has been set up, you need to install <a
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76 HREF="http://www.ssh.fi/">ssh</a>, which is relatively painless. Log
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77 in to cvs.haskell.org, and set up your <tt>.ssh/authorized_keys</tt>
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78 file to allow logins from your local machine without a password (the
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79 ssh documentation has details on how to do this). Then, just
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82 <li> set your <tt>CVSROOT</tt> environment variable to <tt>:ext:<username>@cvs.haskell.org:/home/cvs/root</tt>.
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84 <li>set your<tt> CVS_RSH </tt>environment variable to <tt>ssh</tt>.</li>
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87 <p>The <tt>CVSROOT</tt> environment variable will be recorded in the checked-out tree, so
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88 you don't need to set this every time either. Ignore the instructions for setting <tt>CVSROOT</tt>
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95 <li>Setting your <tt>CVS_RSH</tt> to <tt>ssh</tt> assumes that your CVS client understands
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96 how to execute shell script ("#!"s,really), which is what <tt>ssh</tt> is. This
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97 may not be the case on some platforms (read: Win32), so in that case set <tt>CVS_RSH</tt>
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98 to <tt>ssh1</tt>.</li>
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101 <h2><a NAME="first"></a><b>Using CVS for the First Time</b></h2>
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104 <li>(ok, everybody now...) Firstly, identify which areas of the source tree you'll be
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105 working on. The directory structure looks like this:</li>
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106 <div align="center"><center><table>
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108 <td>fptools/ghc </td>
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112 <td>fptools/happy </td>
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116 <td>fptools/green-card </td>
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117 <td>Green Card</td>
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120 <td>fptools/nofib </td>
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121 <td>Nofib test suite</td>
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124 <td>fptools/hdirect </td>
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125 <td>IDL-to-Haskell compiler</td>
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128 </center></div><p>For each directory, there's a mailing list: <tt>cvs-ghc</tt>, <tt>cvs-nofib</tt>
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129 etc. Everyone on the mailing list is sent a message automatically by CVS whenever someone
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130 checks in a change, this helps to keep track of what's going on when several people are
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131 working on related stuff. To join any of these mailing lists, mail <a
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132 href="mailto:majordomo@haskell.org">majordomo@haskell.org</a>. </p>
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133 <li>Create a .cvsrc file. Mine looks like this:</li>
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134 <pre> checkout -P
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135 release -d
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136 update -P
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137 diff -c</pre>
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138 <p>It just gives default flags for some of the CVS commands. For instance, the -P flag to
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139 'checkout' says prune empty directories, which is normally what you want.</p>
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142 <h2><a NAME="checkout"></a><b>Checking Out a Source Tree</b></h2>
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145 <li>Check out your sources. Make sure you set your <tt>CVSROOT</tt> environment variable
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146 according to either of the remote methods above. The Approved Way (at least by me) to
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147 check out a source tree is as follows:</li>
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148 <pre> $ cvs checkout fpconfig</pre>
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149 <p>At this point you have a new directory called 'fptools' which contains the basic stuff
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150 for the fptools suite - including the configuration files and some other junk. </p>
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151 <pre> $ mv fptools <directory></pre>
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152 <p>You can call the fptools directory whatever you like, CVS won't mind. </p>
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153 <pre> $ cd <directory>
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154 $ cvs checkout ghc happy</pre>
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155 <p>The second command here checks out the relevant modules you want to work on. For a GHC
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156 build, for instance, you need at least the <tt>ghc</tt> module (in fact you can get away
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157 with just that).</p>
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160 <h2><a NAME="commit"></a><b>Committing Your Changes</b></h2>
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162 <p>This is only if you have read-write access to the repository. For anoncvs users, CVS
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163 will issue a "read-only repository" error if you try to commit changes.
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166 <li>Build the software, if necessary. Unless you're just working on documentation, you'll
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167 probably want to build the software in order to test any changes you make. For GHC,
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168 instructions can be found in the GHC installation guide.</li>
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169 <li>Make changes. Preferably small ones first.</li>
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170 <li>Test them. You can see exactly what changes you've made by using the <tt>cvs diff</tt>
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171 command. For example, <pre> $ cvs diff</pre>
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172 <p>lists all the changes (using the <tt>diff</tt> command) in and below the current
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173 directory. In emacs, C-c C-v C-= runs <tt>cvs diff</tt> on the current buffer and shows
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174 you the results.</p>
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176 <li>Before checking in a change, you need to update your source tree:</li>
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177 <pre> $ cd fptools
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178 $ cvs update</pre>
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179 <p>This pulls in any changes that other people have made, and merges them with yours. If
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180 there are any conflicts, CVS will tell you, and you'll have to resolve them before you can
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181 check your changes in. The documentation describes what to do in the event of a conflict. </p>
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182 <p>It's not always necessary to do a full cvs update before checking in a change, since
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183 CVS will always tell you if you try to check in a file that someone else has changed.
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184 However, you should still update at regular intervals to avoid making changes that don't
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185 work in conjuction with changes that someone else made. Keeping an eye on what goes by on
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186 the mailing list can help here. <br>
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189 <li>When you're happy that your change isn't going to break anything, check it in. For a
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190 one-file change:</li>
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191 <pre> $ cvs commit <filename></pre>
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192 <p>CVS will then pop up an editor for you to enter a "commit message", this is
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193 just a short description of what your change does, and will be kept in the history of the
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195 <p>If you're using emacs, simply load up the file into a buffer and type C-x C-q, and
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196 emacs will prompt for a commit message and then check in the file for you. </p>
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197 <p>For a multiple-file change, things are a bit trickier. There are several ways to do
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198 this, but this is the way I find easiest. First type the commit message into a temporary
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199 file. Then either </p>
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200 <pre> $ cvs commit -F <commit-message> <file_1> .... <file_n></pre>
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201 <p>or, if nothing else has changed in this part of the source tree, </p>
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202 <pre> $ cvs commit -F <commit-message> <directory></pre>
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203 <p>where <directory> is a common parent directory for all your changes, and
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204 <commit-message> is the name of the file containing the commit message. </p>
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205 <p>Shortly afterwards, you'll get some mail from the relevant mailing list saying which
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206 files changed, and giving the commit message. For a multiple-file change, you should still
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207 get only *one* message.</p>
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210 <h2><a NAME="update"></a><b>Updating Your Source Tree</b></h2>
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212 <p>It can be tempting to cvs update just part of a source tree to bring in some changes
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213 that someone else has made, or before committing your own changes. This is NOT
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214 RECOMMENDED! Quite often changes in one part of the tree are dependent on changes in
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215 another part of the tree (the <tt>mk/*.mk</tt> files are a good example where problems
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216 crop up quite often). Having an inconsistent tree is a major cause of headaches. </p>
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218 <p>So, to avoid a lot of hassle, follow this recipe for updating your tree: </p>
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221 $ cvs update -Pd 2>&1 | tee log</pre>
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223 <p>Look at the log file, and fix any conflicts (denoted by a 'C' in the first column). If
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224 you're using multiple build trees, then for every build tree you have pointing at this
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225 source tree, you need to update the links in case any new files have appeared: </p>
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227 <pre>$ cd <build-tree>
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228 $ lndir <source-tree></pre>
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230 <p>Some files might have been removed, so you need to remove the links pointing to these
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231 non-existent files: </p>
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233 <pre>$ find . -xtype l -exec rm '{}' \;</pre>
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235 <p>And finally, re-configure to take into accound any changes in mk/config.mk.in. </p>
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237 <pre>$ ./configure</pre>
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239 <p>To be *really* safe, you should do </p>
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241 <pre>$ gmake boot && gmake all</pre>
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243 <p>from the top-level, to update the dependencies and build any changed files. </p>
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245 <h2><a NAME="tags"></a><b>GHC Tag Policy</b></h2>
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247 If you want to check out a particular version of GHC, you'll need to
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248 know how we tag versions in the repository. The policy (as of 4.04)
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252 <li> The tree is branched before every major release. The branch
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253 tag is <tt>ghc-x-xx-branch</tt>, where <tt>x-xx</tt> is the version
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254 number of the release with the <tt>'.'</tt> replaced by a
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255 <tt>'-'</tt>. For example, the 4.04 release lives on
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256 <tt>ghc-4-04-branch</tt>.</li>
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258 <li> The release itself is tagged with <tt>ghc-x-xx</tt> (on the
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259 branch). eg. 4.06 is called <tt>ghc-4-06</tt>.</li>
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261 <li> We didn't always follow these guidelines, so to see what tags
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262 there are for previous versions, do <tt>cvs log</tt> on a file
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263 that's been around for a while (like <tt>fptools/ghc/README</tt>).
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266 So, to check out a fresh GHC 4.06 tree you would do:
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269 $ cvs co -r ghc-4-06 fpconfig
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271 $ cvs co -r ghc-4-06 ghc hslibs
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275 <h2><a NAME="hints"></a><b>General Hints</b></h2>
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278 <li>As a general rule: commit changes in small units, preferably addressing one issue or
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279 implementing a single feature. Provide a descriptive log message so that the repository
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280 records exactly which changes were required to implement a given feature/fix a bug. I've
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281 found this *very* useful in the past for finding out when a particular bug was introduced:
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282 you can just wind back the CVS tree until the bug disappears.</li>
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283 <li>Keep the sources at least *buildable* at any given time. No doubt bugs will creep in,
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284 but it's quite easy to ensure that any change made at least leaves the tree in a buildable
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285 state. We do nightly builds of GHC to keep an eye on what things work/don't work each day
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286 and how we're doing in relation to previous verions. This idea is truely wrecked if the
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287 compiler won't build in the first place!</li>
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288 <li>To check out extra bits into an already-checked-out tree, use the following procedure.
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289 Suppose you have a checked-out fptools tree containing just ghc, and you want to add nofib
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291 <pre> cd fptools
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292 cvs checkout nofib</pre>
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294 <pre> cd fptools
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295 cvs update -d nofib</pre>
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296 <p>(the -d flag tells update to create a new directory). If you just want part of the
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297 nofib suite, you can do </p>
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298 <pre> cd fptools
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299 cvs checkout nofib/spectral</pre>
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300 <p>This works because <tt>nofib</tt> is a module in its own right, and spectral is a
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301 subdirectory of the nofib module. The path argument to checkout must always start with a
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302 module name. There's no equivalent form of this command using <tt>update</tt>.</p>
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305 <h2>Reporting Bugs in the CVS sources</h2>
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307 <p> If you are reporting a bug or infelicity in the CVS version of
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308 GHC, please send your message to </p>
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310 <table align="center">
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312 <a href="mailto:cvs-ghc@haskell.org">cvs-ghc@haskell.org</a><td></td>
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315 <a href="mailto:cvs-hslibs@haskell.org">cvs-hslibs@haskell.org</a>
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316 <td>(for hslibs/ stuff)</td>
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319 <a href="mailto:cvs-nofib@haskell.org">cvs-nofib@haskell.org</a>
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320 <td>(for nofib/ stuff)</td>
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324 <p>(not to glasgow-haskell-bugs). Two reasons:</p>
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327 <li> Readers of glasgow-haskell-bugs will get less junk mail</li>
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329 <li> I'm a little worried that ghc-bugs readers are beginning to think
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330 "is ghc really this unreliable?"! The checked-in-last-night version
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331 of GHC just isn't going to be solid. No one expects it to be. But
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332 a casual reader might not distinguish.</li>
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335 <p>Please don't stop sending bug reports though. They are really useful.</p>
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339 <p>Ok, that'll do for now. If there's anything else you'd like to see
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340 in this file, just let us know. </p>
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344 <td><a HREF="mailto:jlewis@cse.ogi.edu">Jeff Lewis</a> </td>
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347 <td><a HREF="mailto:simonm@dcs.gla.ac.uk">Simon Marlow</a> </td>
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projects / ghc-hetmet.git / blob