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   9                         <h1>Dscho's Git log</h1>
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  11                         <table width=400px bgcolor=#e0e0e0 border=1>
  12                         <tr><th>Table of contents:</th></tr>
  13                         <tr><td>
  14                         <p><ul>
  15                         <li><a href=#1239975597>17 Apr 2009 No time for Git</a>
  16                         <li><a href=#1238970571>06 Apr 2009 How to recover from a hackathon</a>
  17                         <li><a href=#1236554268>09 Mar 2009 So, what is missing from my <i>rebase-i-p</i> branch?</a>
  18                         <li><a href=#1236479389>08 Mar 2009 New Git for Windows version</a>
  19                         <li><a href=#1235092615>20 Feb 2009 Code reviews</a>
  20                         <li><a href=#1234409395>12 Feb 2009 Interactive <i>rebase</i> just learnt a new command: <i>topic</i></a>
  21                         <li><a href=#1234320806>11 Feb 2009 Thunderbird, oh Thunderbird, you always make my small brain hurt</a>
  22                         <li><a href=#1234141489>09 Feb 2009 <i>format-patch --thread</i> and Alpine</a>
  23                         <li><a href=#1234140696>09 Feb 2009 <i>rebase</i> updates</a>
  24                         <li><a href=#1234040744>07 Feb 2009 The infamous <i>mark</i> command in the <i>rebase</i> command</a>
  25                         </ul></p>
  26                         <a href=dscho.git?a=blob_plain;hb=4efb9dfc1f5b0ebdb59ceb849e602b0d598ef61c;f=index.html>Older posts</a>
  27                         </td></tr></table>
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  36                         <table width=400px bgcolor=#e0e0e0 border=1>
  37                         <tr><th>About this blog:</th></tr>
  38                         <tr><td>
  39                         <p>It is an active <a href=http://repo.or.cz/w/git/dscho.git?a=blob_plain;f=index.html;hb=5f002cab57a837125a8f901bcd1f3c1477bc3119>abuse</a> of <a href=http://repo.or.cz/>repo.or.cz</a>,
  40                         letting gitweb unpack the objects in the current tip of the branch <i>blog</i>,
  41                         including the images and the RSS feed.
  42                         </p><p>
  43                         Publishing means running a script that collects the posts, turns them into
  44                         HTML, makes sure all the images are checked in, and pushes the result.
  45                         </p><p>
  46                         This blog also serves to grace the world with Dscho's random thoughts on and
  47                         around Git.
  48                         </p>
  49                         </td></tr></table>
  50                         <br>
  51                         <table width=400px bgcolor=#e0e0e0 border=1>
  52                         <tr><th>Links:</th></tr>
  53                         <tr><td>
  54                         <ul>
  55                         <li> <a href=http://git-scm.com/>Git's homepage</a>
  56                         <li> <a href=http://gitster.livejournal.com/>Junio's blog</a>
  57                         <li> <a href=http://www.spearce.org/>Shawn's blog</a> seems to be sitting
  58                               idle ever since he started working for Google...
  59                         <li> <a href=http://torvalds-family.blogspot.com/>Linus' blog</a> does not
  60                               talk much about Git...
  61                         <li> Scott Chacon's <a href=http://whygitisbetterthanx.com/>Why Git is better
  62                              than X</a> site
  63                         <li> <a href=http://vilain.net/>The blog of mugwump</a>
  64                         <li> <a href=http://merlyn.vox.com/>Merlyn's blog</a>
  65                         <li> <a href=http://blogs.gnome.org/newren/>Elijah Newren</a> chose the
  66                               same path as Cogito, offering an alternative porcelain (an approach
  67                               that is doomed in my opinion)
  68                         <li> <a href=http://msysgit.googlecode.com/>The msysGit project</a>, a (mostly)
  69                               failed experiment to lure the many Windows developers out there to
  70                               contribute to Open Source for a change.
  71                         </ul>
  72                         </td></tr></table>
  73                         <br>
  74                         <table width=400px bgcolor=#e0e0e0 border=1>
  75                         <tr><th>Google Ads:</th></tr>
  76                         <tr><td>
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  86                         src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
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  88                         </td></tr></table>
  89                         </div>
  90                         <h6>Friday, 17th of April, Anno Domini MMIX, at the hour of the Monkey</h6>
  91                         <a name=1239975597>
  92                         <h2>No time for Git</h2>
  93
  94                         <p>
  95                         </p><p>
  96                         It is a shame, but most of my Git time budget is taken by msysGit these
  97                         days.
  98                         </p><p>
  99                         But at least msysGit is moving again; I'll probably write a Herald about
 100                         it.
 101                         </p>
 102                         <h6>Monday, 6th of April, Anno Domini MMIX, at the hour of the Rat</h6>
 103                         <a name=1238970571>
 104                         <h2>How to recover from a hackathon</h2>
 105
 106                         <p>
 107                         </p><p>
 108                         Phew, 2 crazy and fantastic weeks are behind me.  But it takes its toll:
 109                         a weekend I was more offline than online.
 110                         </p><p>
 111                         Things that are important now: relax. sleep. take a walk. learn to sleep
 112                         more than 4 hours a night again. learn to watch a movie without thinking
 113                         about code. go for a run.
 114                         </p><p>
 115                         And after recovering, back to the rebase-i-p branch!
 116                         </p>
 117                         <h6>Monday, 9th of March, Anno Domini MMIX, at the hour of the Rat</h6>
 118                         <a name=1236554268>
 119                         <h2>So, what is missing from my <i>rebase-i-p</i> branch?</h2>
 120
 121                         <p>
 122                         </p><p>
 123                         I regularly use <i>rebase -i -p</i> these days, to update my personal Git
 124                         tree (which used to be <i>my-next</i>).
 125                         </p><p>
 126                         There are a few things missing before I can start assembling a patch
 127                         series for submission:
 128                         </p><p>
 129                         <ul>
 130                         <li>I need to handle the commit parents which are outside of the rebased
 131                         ones properly.  In other words, when a commit is picked whose parent is
 132                         not rebased, it needs to be rebased onto $ONTO.
 133                         <li>The patch which uses patch-id to generate DROPPED directly also tries to
 134                         consolidate the handling of DROPPED commits by putting them into REWRITTEN
 135                         instead of DROPPED, but that breaks the tests.  So, this patch needs to be
 136                         split.
 137                         <li>I want to introduce one more command, <i>rephrase</i>, which allows you to
 138                         modify the commit message, and nothing more, and <i>halt</i>, which does the
 139                         same as <i>edit</i> without <i>pick</i>.  Then there needs to be a new test script
 140                         for those commands, and this will be an early patch series.
 141                         <li>Time.  I need time, desperately.  If my day job was not as exciting as it
 142                         is, I would have more time for Git.  As it is, I have to budget my time so
 143                         that I get anything done at all.
 144                         </ul>
 145                         </p><p>
 146                         These issues have been postponed due to Steffen taking a well-deserved
 147                         vacation, which means that I have to act as msysGit maintainer again.
 148                         </p><p>
 149                         And this coming week, I will have other things to do in all likeliness, so
 150                         that I expect to be able to submit a <i>rebase -i -p</i> patch series only next
 151                         week.  If not then, due to a heavy workload, it will be postponed to early
 152                         April.
 153                         </p><p>
 154                         Oh well, the joys of being excited by several competing projects! &#x263a;
 155                         </p>
 156                         <h6>Sunday, 8th of March, Anno Domini MMIX, at the hour of the Tiger</h6>
 157                         <a name=1236479389>
 158                         <h2>New Git for Windows version</h2>
 159
 160                         <p>
 161                         </p><p>
 162                         Phew.  That was quite a day, almost exclusively spent on finishing that
 163                         installer.  The worst part: updating GCC seemed not to be such a good idea
 164                         after all...
 165                         </p><p>
 166                         For Windows, we need to use the printf format <i>%I64u</i> (which is
 167                         non-standard, in the common way of Microsoft) if you want to print 64-bit
 168                         wide unsigned numbers.  The rest of the world accepts the standard <i>%llu</i>.
 169                         </p><p>
 170                         After upgrading to the new GCC, a lot of warnings appeared, complaining
 171                         about <i>%I64u</i>.  The warnings went away when I replaced the format with
 172                         <i>%llu</i>.
 173                         </p><p>
 174                         Being the naive I am, I mistook that for a sign that we could finally go
 175                         more standards-compliant.
 176                         </p><p>
 177                         However, it only means that we have to live with the warnings for now, as
 178                         the C runtime provided on Windows still strongly disagrees with standards
 179                         (and it has to continue to do so, lest it break existing programs).
 180                         </p><p>
 181                         Sigh.
 182                         </p><p>
 183                         At least I have the feeling that I caught the most important bugs before
 184                         releasing.
 185                         </p>
 186                         <h6>Friday, 20th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 187                         <a name=1235092615>
 188                         <h2>Code reviews</h2>
 189
 190                         <p>
 191                         </p><p>
 192                         It has been said that reviewing patches is a most thankless job.  As I really
 193                         like the elegance of Git's source code, and care a lot about it, I did not
 194                         think that it was thankless, just a little bit tedious (especially when the
 195                         patch authors mistake criticism for personal attacks).
 196                         </p><p>
 197                         Usually, I am pretty good at ignoring insults as responses to my comments;
 198                         after all, I have a lot more enjoyable things to do than to spend time talking
 199                         to a guy who shows how wise he is when he thinks that I criticize him
 200                         <u>personally</u> when I just try to enhance his work, by offering a little bit of
 201                         my knowledge.
 202                         </p><p>
 203                         However, in the last days, three people really seemed to want to insult me,
 204                         to make me go away, to stop the fun I have with Git.
 205                         </p><p>
 206                         And they almost succeeded.
 207                         </p><p>
 208                         So I guess it is time to reassess my priorities, and maybe stop reviewing
 209                         Git patches altogether.
 210                         </p>
 211                         <h6>Thursday, 12th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 212                         <a name=1234409395>
 213                         <h2>Interactive <i>rebase</i> just learnt a new command: <i>topic</i></h2>
 214
 215                         <p>
 216                         </p><p>
 217                         Today I am pretty pleased with myself.  Two projects at my day job got a real
 218                         boost, and I implemented a shortcut that avoids the ugly 'bookmark' statement
 219                         in rebase scripts most of the time.
 220                         </p><p>
 221                         A typical rebase script, generated by <i>git rebase -i -p $COMMIT</i> will look
 222                         something like this:
 223                         </p><p>
 224                         <table
 225                                                         border=1 bgcolor=black>
 226                                                 <tr><td bgcolor=lightblue colspan=3>
 227                                 <pre>                                                                                </pre>
 228                         </td></tr>
 229                         <tr><td>
 230                                 <table cellspacing=5 border=0
 231                                          style="color:white;">
 232                                 <tr><td>
 233                                         <pre>
 234 pick 1234567 My first commit
 235 topic begin super-cool-feature
 236 pick 2345678 The super cool feature
 237 pick 3456789 Documentation for the super cool feature
 238 topic end super-cool-feature
 239 </pre>
 240                                                         </td></tr>
 241                                                         </table>
 242                                                 </td></tr>
 243                                                 </table>
 244                         </p><p>
 245                         The result will be a merge commit at the HEAD whose first parent is
 246                         "My first commit", whose second parent is "Documentation for the super
 247                         cool feature" and whose commit message is "Merge branch 'super-cool-feature'".
 248                         </p><p>
 249                         Side note: internally, <i>topic begin $NAME [at $COMMIT]</i> will be handled as if
 250                         you wrote <i>bookmark merge-parent-of-$NAME; goto $COMMIT</i>, and
 251                         <i>topic end $NAME [$MESSAGE]</i> will be handled as if you wrote
 252                         <i>bookmark $NAME; goto merge-parent-of-$NAME; merge parents $NAME [original $MARK Merge branch '$NAME']</i>.
 253                         </p><p>
 254                         Of course, being more concise, the 'topic' statement is not only nicer to the
 255                         eye, but also less error-prone.
 256                         </p><p>
 257                         And hopefully many people will agree with me that this rebase script is pretty
 258                         intuitive.
 259                         </p>
 260                         <h6>Wednesday, 11th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 261                         <a name=1234320806>
 262                         <h2>Thunderbird, oh Thunderbird, you always make my small brain hurt</h2>
 263
 264                         <p>
 265                         </p><p>
 266                         There was a lengthy discussion on the Git mailing list about using Thunderbird,
 267                         a not quite unpopular mailing program, to send inline patches.
 268                         </p><p>
 269                         It is really kind of sad that the Thunderbird developers do not see how
 270                         stubbornly they offend quite a number of people and scare them away from their
 271                         program.  After all, you should try to be liberal in what you accept and strict
 272                         in what you emit.  No, that does not mean that you should force others to
 273                         switch their mailers because you strictly adher to your philosophy in what you
 274                         emit, ignoring the rest of the world.
 275                         </p><p>
 276                         In any case, I am not affected (as long as I do not get mails from a poor soul
 277                         stuck with Thunderbird).
 278                         </p><p>
 279                         But I was a bit mean to that Thunderbird guy I dragged into the discussion, and
 280                         he seems really offended.
 281                         </p><p>
 282                         So I thought I'd give him a real reason to feel offended: I'll just do his work:
 283                         </p><p>
 284                         http://<a href=http://repo.or.cz>repo.or.cz</a>/w/UnFlowedThunderbird.git
 285                         </p><p>
 286                         It took my free time of two days, being not a Thunderbird developer myself.
 287                         Hopefully it works, and hopefully some people will feel really ashamed now.
 288                         </p>
 289                         <h6>Monday, 9th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 290                         <a name=1234141489>
 291                         <h2><i>format-patch --thread</i> and Alpine</h2>
 292
 293                         <p>
 294                         </p><p>
 295                         I started recently to pipe the output of
 296                         <i>git format-patch --cover-letter --stdout ...</i> directly into the
 297                         <i>postponed-msgs</i> folder Alpine uses, instead of pasting files into the
 298                         mailer.
 299                         </p><p>
 300                         The idea is to pretend that I continue a postponed mail, but in reality I
 301                         never wrote it, <i>format-patch</i> did.
 302                         </p><p>
 303                         However, I had problems with the <i>--thread</i> option that is implied by
 304                         <i>--cover-letter</i>.  Alpine always generated new message IDs without adjusting
 305                         the <i>In-reply-to:</i> and <i>References:</i> headers of the other mails.
 306                         </p><p>
 307                         Now I found out that the reason is that the <i>Fcc:</i> headers were missing in
 308                         the mails, and Alpine generated them, making up new message IDs in the process.
 309                         </p><p>
 310                         Therefore I have an alias now which sets not only the <i>Fcc:</i> header, but also
 311                         the <i>To:</i> headers by rewriting the stream using <i>sed</i>.  This is slightly
 312                         ugly, but so is the handling of headers in <i>format-patch</i>: if you thought
 313                         you could specify arbitrary headers using the command line, you are mistaken:
 314                         you can do that only by editing the config.
 315                         </p><p>
 316                         While at it, I also noticed a bug whereby <i>--thread --in-reply-to=...</i> simply
 317                         forgets the <i>--thread</i>.  Maybe this week I will find time to address this bug.
 318                         </p>
 319                         <h6>Monday, 9th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 320                         <a name=1234140696>
 321                         <h2><i>rebase</i> updates</h2>
 322
 323                         <p>
 324                         </p><p>
 325                         Phew.  The last few days, I was mainly chasing bugs I introduced due to being
 326                         too tired to work on the merge-preserving, interactive <i>rebase</i>.
 327                         </p><p>
 328                         But finally I have something I can start working with.  After my failed
 329                         experiment to use git-blame to split topic branches, I will sort the commits
 330                         in my <i>my-next</i> branch into topic branches manually.
 331                         </p><p>
 332                         Then I will add an option to <i>rebase -i -p</i> to rewrite refs which point to
 333                         rewritten commits, so that I can have branches <i>rebase-i-p</i>, <i>add-e</i>, etc
 334                         and all of them are automatically updated when I <i>rebase -i -p</i> the <i>my-next</i>
 335                         branch.
 336                         </p><p>
 337                         In the process, not only have I learnt the value of the <i>bookmark</i> command,
 338                         but made quite a few-much needed cleanups (which make
 339                         <i>git-rebase--interactive.sh</i> longer, but much more understandable).
 340                         </p><p>
 341                         Hopefully Stephan will pick the changes in the "rebase protocol" up, and then
 342                         we can have a sequencer with which I can start to make a graphical interactive
 343                         rebase using git-gui.  Or gitk.
 344                         </p><p>
 345                         Maybe.
 346                         </p>
 347                         <h6>Saturday, 7th of February, Anno Domini MMIX, at the hour of the Pig</h6>
 348                         <a name=1234040744>
 349                         <h2>The infamous <i>mark</i> command in the <i>rebase</i> command</h2>
 350
 351                         <p>
 352                         </p><p>
 353                         I realized today how easy it is to lose commits with the "merge preserving"
 354                         mode of the interactive rebase.  In my case, it was when I tried to move a
 355                         bunch of commits from the tip of my branch into a topic branch.
 356                         </p><p>
 357                         But after moving the commits, I forgot to update the parent of the merge
 358                         commit.  Possibly a mark command could have helped.  The very same command
 359                         I called a nightmare for usability.
 360                         </p><p>
 361                         So I was wrong.  Big news.  &#x263a;
 362                         </p><p>
 363                         However, I think that the syntax "mark :1" is something best left for
 364                         machine consumption, not for human beings.
 365                         </p><p>
 366                         But I have an idea: we could use some garbled commit subject, or in case of
 367                         merge parents, the merge subject as some human readable title of the mark.
 368                         </p><p>
 369                         The rebase script would then look something like this:
 370                         </p><p>
 371                         <table
 372                                                         border=1 bgcolor=black>
 373                                                 <tr><td bgcolor=lightblue colspan=3>
 374                                 <pre>                                                                                </pre>
 375                         </td></tr>
 376                         <tr><td>
 377                                 <table cellspacing=5 border=0
 378                                          style="color:white;">
 379                                 <tr><td>
 380                                         <pre>
 381 pick abcdefg Some ultra cool commit
 382 bookmark ultra-cool
 383 goto upstream
 384 pick hijklmn Some other cool commit
 385 merge parent ultra-cool Merge 'ultra-cool' into master
 386 </pre>
 387                                                         </td></tr>
 388                                                         </table>
 389                                                 </td></tr>
 390                                                 </table>
 391                         </p><p>
 392                         The good news is: I added code that refuses to finish a rebase when there
 393                         are commits that were rewritten, but not part of the new HEAD's ancestry.
 394                         </p>
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