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   9                         <h1>Dscho's Git log</h1>
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  11                         <table width=400px bgcolor=#e0e0e0 border=0>
  12                         <tr><th>Table of contents:</th></tr>
  13                         <tr><td>
  14                         <p><ul>
  15                         <li><a href=#1245419588>19 Jun 2009 The GraphGUI project</a>
  16                         <li><a href=#1242408298>15 May 2009 Wasting way too much time on msysGit</a>
  17                         <li><a href=#1241995759>11 May 2009 Working on jgit diff</a>
  18                         <li><a href=#1239975597>17 Apr 2009 No time for Git</a>
  19                         <li><a href=#1238970571>06 Apr 2009 How to recover from a hackathon</a>
  20                         <li><a href=#1236554268>09 Mar 2009 So, what is missing from my <i>rebase-i-p</i> branch?</a>
  21                         <li><a href=#1236479389>08 Mar 2009 New Git for Windows version</a>
  22                         <li><a href=#1235092615>20 Feb 2009 Code reviews</a>
  23                         <li><a href=#1234409395>12 Feb 2009 Interactive <i>rebase</i> just learnt a new command: <i>topic</i></a>
  24                         <li><a href=#1234320806>11 Feb 2009 Thunderbird, oh Thunderbird, you always make my small brain hurt</a>
  25                         </ul></p>
  26                         <a href=dscho.git?a=blob_plain;hb=24c89f93817dce2de43bbcaa631c3d7367699778;f=index.html>Older posts</a>
  27                         </td></tr></table>
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  30                         <a href="dscho.git?a=blob_plain;hb=blog;f=blog.rss"
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  36                         <table width=400px bgcolor=#e0e0e0 border=0>
  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=0>
  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=0>
  75                         <tr><th>Google Ads:</th></tr>
  76                         <tr><td>
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  88                         </td></tr></table>
  89                         </div>
  90                         <h6>Friday, 19th of June, Anno Domini MMIX, at the hour of the Monkey</h6>
  91                         <a name=1245419588>
  92                         <h2>The GraphGUI project</h2>
  93
  94                         <p>
  95                         </p><p>
  96                         After a few unfortunate delays (and some fortunate ones, just not for us), the
  97                         GraphGUI project finally takes off.  A quick first glance:
  98                         </p><p>
  99                         <center><img src=dscho.git?a=blob_plain;hb=c33212b23b2b3e45c14403efe82cabb1cd53f6e3;f=basic-gui.jpg basic-gui.jpg></center>
 100                         </p><p>
 101                         The delays were a bit unnerving, but the student is really bright and still
 102                         has the chance to pull the project off.
 103                         </p><p>
 104                         Next plans are to show text, too, to invent a rudimentary layout engine that
 105                         can be adjusted manually (this is in contrast to <i>gitk</i> or <i>log --graph</i>).
 106                         </p><p>
 107                         After that, integration into JGit (this probably triggered the eGit/JGit
 108                         split).
 109                         </p><p>
 110                         And then we'll go wild!
 111                         </p>
 112                         <h6>Friday, 15th of May, Anno Domini MMIX, at the hour of the Dog</h6>
 113                         <a name=1242408298>
 114                         <h2>Wasting way too much time on msysGit</h2>
 115
 116                         <p>
 117                         </p><p>
 118                         I recently got into the bad habit of spending a large amount of my waking
 119                         hours working on msysGit, more than is really healthy for me.
 120                         </p><p>
 121                         For example, I spent the whole morning -- when I should have worked on a
 122                         very important day-job project -- on trying to fix issue 258, where
 123                         <i>git web--browse</i> does not work as expected because of quoting issues
 124                         with cmd.exe.
 125                         </p><p>
 126                         This is reducing my Git time budget to negative numbers, so much so that I
 127                         cannot even work on Git projects that I actually like, such as <i>jgit diff</i>
 128                         or <i>git rebase -i -p</i>, or at least projects I felt obliged to continue
 129                         to work on, such as <i>git notes</i>.
 130                         </p><p>
 131                         Now, some people who tried to teach me some time management strongly
 132                         criticized me for ignoring their lessons, and unfortunately, I have to agree.
 133                         </p><p>
 134                         The problem is that I would <u>hate</u> to see msysGit fall to the same state it
 135                         was after I stopped working on it last year.  I started it, and I would like
 136                         it to grow, but too few people took care of the issue tracker, too few tried
 137                         to debug their problems themselves, too few submitted fixes.
 138                         </p><p>
 139                         I note, though, that there is a positive trend.  But being the impatient person
 140                         I am ("2 seconds is my attention span") I tend to want the trend to be more
 141                         impressive.
 142                         </p><p>
 143                         Anyway, no work on msysGit for at least 4 days, that's what the doctor (me)
 144                         said...
 145                         </p>
 146                         <h6>Monday, 11th of May, Anno Domini MMIX, at the hour of the Rat</h6>
 147                         <a name=1241995759>
 148                         <h2>Working on jgit diff</h2>
 149
 150                         <p>
 151                         </p><p>
 152                         Shawn did so many useful things that I use on a daily basis that I felt really
 153                         awful when I realized just how <u>long</u> I had promised to clean up that diff
 154                         implementation I wrote for JGit.
 155                         </p><p>
 156                         Alas, it appears that the thing turned out to be almost a complete rewrite, as
 157                         the original implementation walked the edit graph in a rather inefficient way.
 158                         </p><p>
 159                         A little background: Myers' algorithm to generate "an edit script" works on
 160                         the <i>edit graph</i>: imagine you have all lines of file <i>A</i> as columns and
 161                         all lines of file <i>B</i> as rows, then the <i>edit graph</i> is a connection of
 162                         the upper left corner to the lower right corner, containing only horizontal,
 163                         vertical or diagonal elements, where diagonal elements are only allowed when
 164                         the lines of both files agree at that point:
 165                         </p><p>
 166 <pre>
 167  H E L L O , W O R L D
 168  ----
 169 L    \
 170       ---
 171 O        \
 172           ---
 173 W            \
 174               --------
 175 </pre>
 176                         </p><p>
 177                         The <i>shortest</i> edit path minimizes the number of non-diagonal elements.
 178                         </p><p>
 179                         Myers' idea is to develop forward and backward paths at the same time
 180                         (increasing the number of non-diagonal elements uniformly), storing
 181                         only the latest end points.  Once the paths meet, divide and conquer.
 182                         </p><p>
 183                         In theory, it would be quicker to store <u>all</u> end points and then just
 184                         reconstruct the shortest paths, alas, this takes way too much memory.
 185                         </p><p>
 186                         My first implementation did not remember start or end of the non-diagonal
 187                         parts, and had to recurse way more often than really necessary (in the end,
 188                         we will order the non-diagonal parts into horizontal and vertical parts
 189                         anyway, so start and end are sufficient).
 190                         </p><p>
 191                         The current progress can be seen <a href=http://repo.or.cz/w/egit/dscho.git/>
 192                         here</a>.
 193                         </p>
 194                         <h6>Friday, 17th of April, Anno Domini MMIX, at the hour of the Monkey</h6>
 195                         <a name=1239975597>
 196                         <h2>No time for Git</h2>
 197
 198                         <p>
 199                         </p><p>
 200                         It is a shame, but most of my Git time budget is taken by msysGit these
 201                         days.
 202                         </p><p>
 203                         But at least msysGit is moving again; I'll probably write a Herald about
 204                         it.
 205                         </p>
 206                         <h6>Monday, 6th of April, Anno Domini MMIX, at the hour of the Rat</h6>
 207                         <a name=1238970571>
 208                         <h2>How to recover from a hackathon</h2>
 209
 210                         <p>
 211                         </p><p>
 212                         Phew, 2 crazy and fantastic weeks are behind me.  But it takes its toll:
 213                         a weekend I was more offline than online.
 214                         </p><p>
 215                         Things that are important now: relax. sleep. take a walk. learn to sleep
 216                         more than 4 hours a night again. learn to watch a movie without thinking
 217                         about code. go for a run.
 218                         </p><p>
 219                         And after recovering, back to the rebase-i-p branch!
 220                         </p>
 221                         <h6>Monday, 9th of March, Anno Domini MMIX, at the hour of the Rat</h6>
 222                         <a name=1236554268>
 223                         <h2>So, what is missing from my <i>rebase-i-p</i> branch?</h2>
 224
 225                         <p>
 226                         </p><p>
 227                         I regularly use <i>rebase -i -p</i> these days, to update my personal Git
 228                         tree (which used to be <i>my-next</i>).
 229                         </p><p>
 230                         There are a few things missing before I can start assembling a patch
 231                         series for submission:
 232                         </p><p>
 233                         <ul>
 234                         <li>I need to handle the commit parents which are outside of the rebased
 235                         ones properly.  In other words, when a commit is picked whose parent is
 236                         not rebased, it needs to be rebased onto $ONTO.
 237                         <li>The patch which uses patch-id to generate DROPPED directly also tries to
 238                         consolidate the handling of DROPPED commits by putting them into REWRITTEN
 239                         instead of DROPPED, but that breaks the tests.  So, this patch needs to be
 240                         split.
 241                         <li>I want to introduce one more command, <i>rephrase</i>, which allows you to
 242                         modify the commit message, and nothing more, and <i>halt</i>, which does the
 243                         same as <i>edit</i> without <i>pick</i>.  Then there needs to be a new test script
 244                         for those commands, and this will be an early patch series.
 245                         <li>Time.  I need time, desperately.  If my day job was not as exciting as it
 246                         is, I would have more time for Git.  As it is, I have to budget my time so
 247                         that I get anything done at all.
 248                         </ul>
 249                         </p><p>
 250                         These issues have been postponed due to Steffen taking a well-deserved
 251                         vacation, which means that I have to act as msysGit maintainer again.
 252                         </p><p>
 253                         And this coming week, I will have other things to do in all likeliness, so
 254                         that I expect to be able to submit a <i>rebase -i -p</i> patch series only next
 255                         week.  If not then, due to a heavy workload, it will be postponed to early
 256                         April.
 257                         </p><p>
 258                         Oh well, the joys of being excited by several competing projects! &#x263a;
 259                         </p>
 260                         <h6>Sunday, 8th of March, Anno Domini MMIX, at the hour of the Tiger</h6>
 261                         <a name=1236479389>
 262                         <h2>New Git for Windows version</h2>
 263
 264                         <p>
 265                         </p><p>
 266                         Phew.  That was quite a day, almost exclusively spent on finishing that
 267                         installer.  The worst part: updating GCC seemed not to be such a good idea
 268                         after all...
 269                         </p><p>
 270                         For Windows, we need to use the printf format <i>%I64u</i> (which is
 271                         non-standard, in the common way of Microsoft) if you want to print 64-bit
 272                         wide unsigned numbers.  The rest of the world accepts the standard <i>%llu</i>.
 273                         </p><p>
 274                         After upgrading to the new GCC, a lot of warnings appeared, complaining
 275                         about <i>%I64u</i>.  The warnings went away when I replaced the format with
 276                         <i>%llu</i>.
 277                         </p><p>
 278                         Being the naive I am, I mistook that for a sign that we could finally go
 279                         more standards-compliant.
 280                         </p><p>
 281                         However, it only means that we have to live with the warnings for now, as
 282                         the C runtime provided on Windows still strongly disagrees with standards
 283                         (and it has to continue to do so, lest it break existing programs).
 284                         </p><p>
 285                         Sigh.
 286                         </p><p>
 287                         At least I have the feeling that I caught the most important bugs before
 288                         releasing.
 289                         </p>
 290                         <h6>Friday, 20th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 291                         <a name=1235092615>
 292                         <h2>Code reviews</h2>
 293
 294                         <p>
 295                         </p><p>
 296                         It has been said that reviewing patches is a most thankless job.  As I really
 297                         like the elegance of Git's source code, and care a lot about it, I did not
 298                         think that it was thankless, just a little bit tedious (especially when the
 299                         patch authors mistake criticism for personal attacks).
 300                         </p><p>
 301                         Usually, I am pretty good at ignoring insults as responses to my comments;
 302                         after all, I have a lot more enjoyable things to do than to spend time talking
 303                         to a guy who shows how wise he is when he thinks that I criticize him
 304                         <u>personally</u> when I just try to enhance his work, by offering a little bit of
 305                         my knowledge.
 306                         </p><p>
 307                         However, in the last days, three people really seemed to want to insult me,
 308                         to make me go away, to stop the fun I have with Git.
 309                         </p><p>
 310                         And they almost succeeded.
 311                         </p><p>
 312                         So I guess it is time to reassess my priorities, and maybe stop reviewing
 313                         Git patches altogether.
 314                         </p>
 315                         <h6>Thursday, 12th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 316                         <a name=1234409395>
 317                         <h2>Interactive <i>rebase</i> just learnt a new command: <i>topic</i></h2>
 318
 319                         <p>
 320                         </p><p>
 321                         Today I am pretty pleased with myself.  Two projects at my day job got a real
 322                         boost, and I implemented a shortcut that avoids the ugly 'bookmark' statement
 323                         in rebase scripts most of the time.
 324                         </p><p>
 325                         A typical rebase script, generated by <i>git rebase -i -p $COMMIT</i> will look
 326                         something like this:
 327                         </p><p>
 328                         <table
 329                                                         border=1 bgcolor=black>
 330                                                 <tr><td bgcolor=lightblue colspan=3>
 331                                 <pre>                                                                                </pre>
 332                         </td></tr>
 333                         <tr><td>
 334                                 <table cellspacing=5 border=0
 335                                          style="color:white;">
 336                                 <tr><td>
 337                                         <pre>
 338 pick 1234567 My first commit
 339 topic begin super-cool-feature
 340 pick 2345678 The super cool feature
 341 pick 3456789 Documentation for the super cool feature
 342 topic end super-cool-feature
 343 </pre>
 344                                                         </td></tr>
 345                                                         </table>
 346                                                 </td></tr>
 347                                                 </table>
 348                         </p><p>
 349                         The result will be a merge commit at the HEAD whose first parent is
 350                         "My first commit", whose second parent is "Documentation for the super
 351                         cool feature" and whose commit message is "Merge branch 'super-cool-feature'".
 352                         </p><p>
 353                         Side note: internally, <i>topic begin $NAME [at $COMMIT]</i> will be handled as if
 354                         you wrote <i>bookmark merge-parent-of-$NAME; goto $COMMIT</i>, and
 355                         <i>topic end $NAME [$MESSAGE]</i> will be handled as if you wrote
 356                         <i>bookmark $NAME; goto merge-parent-of-$NAME; merge parents $NAME [original $MARK Merge branch '$NAME']</i>.
 357                         </p><p>
 358                         Of course, being more concise, the 'topic' statement is not only nicer to the
 359                         eye, but also less error-prone.
 360                         </p><p>
 361                         And hopefully many people will agree with me that this rebase script is pretty
 362                         intuitive.
 363                         </p>
 364                         <h6>Wednesday, 11th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 365                         <a name=1234320806>
 366                         <h2>Thunderbird, oh Thunderbird, you always make my small brain hurt</h2>
 367
 368                         <p>
 369                         </p><p>
 370                         There was a lengthy discussion on the Git mailing list about using Thunderbird,
 371                         a not quite unpopular mailing program, to send inline patches.
 372                         </p><p>
 373                         It is really kind of sad that the Thunderbird developers do not see how
 374                         stubbornly they offend quite a number of people and scare them away from their
 375                         program.  After all, you should try to be liberal in what you accept and strict
 376                         in what you emit.  No, that does not mean that you should force others to
 377                         switch their mailers because you strictly adher to your philosophy in what you
 378                         emit, ignoring the rest of the world.
 379                         </p><p>
 380                         In any case, I am not affected (as long as I do not get mails from a poor soul
 381                         stuck with Thunderbird).
 382                         </p><p>
 383                         But I was a bit mean to that Thunderbird guy I dragged into the discussion, and
 384                         he seems really offended.
 385                         </p><p>
 386                         So I thought I'd give him a real reason to feel offended: I'll just do his work:
 387                         </p><p>
 388                         http://repo.or.cz/w/UnFlowedThunderbird.git
 389                         </p><p>
 390                         It took my free time of two days, being not a Thunderbird developer myself.
 391                         Hopefully it works, and hopefully some people will feel really ashamed now.
 392                         </p>
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