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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=#1238970571>06 Apr 2009 How to recover from a hackathon</a>
  16                         <li><a href=#1236554268>09 Mar 2009 So, what is missing from my <i>rebase-i-p</i> branch?</a>
  17                         <li><a href=#1236479389>08 Mar 2009 New Git for Windows version</a>
  18                         <li><a href=#1235092615>20 Feb 2009 Code reviews</a>
  19                         <li><a href=#1234409395>12 Feb 2009 Interactive <i>rebase</i> just learnt a new command: <i>topic</i></a>
  20                         <li><a href=#1234320806>11 Feb 2009 Thunderbird, oh Thunderbird, you always make my small brain hurt</a>
  21                         <li><a href=#1234141489>09 Feb 2009 <i>format-patch --thread</i> and Alpine</a>
  22                         <li><a href=#1234140696>09 Feb 2009 <i>rebase</i> updates</a>
  23                         <li><a href=#1234040744>07 Feb 2009 The infamous <i>mark</i> command in the <i>rebase</i> command</a>
  24                         <li><a href=#1233707628>04 Feb 2009 New valgrind series</a>
  25                         </ul></p>
  26                         <a href=dscho.git?a=blob_plain;hb=2b3b3c28ace47f7d23df486052e6a7aa26a05e14;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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  89                         </div>
  90                         <h6>Monday, 6th of April, Anno Domini MMIX, at the hour of the Rat</h6>
  91                         <a name=1238970571>
  92                         <h2>How to recover from a hackathon</h2>
  93
  94                         <p>
  95                         </p><p>
  96                         Phew, 2 crazy and fantastic weeks are behind me.  But it takes its toll:
  97                         a weekend I was more offline than online.
  98                         </p><p>
  99                         Things that are important now: relax. sleep. take a walk. learn to sleep
 100                         more than 4 hours a night again. learn to watch a movie without thinking
 101                         about code. go for a run.
 102                         </p><p>
 103                         And after recovering, back to the rebase-i-p branch!
 104                         </p>
 105                         <h6>Monday, 9th of March, Anno Domini MMIX, at the hour of the Rat</h6>
 106                         <a name=1236554268>
 107                         <h2>So, what is missing from my <i>rebase-i-p</i> branch?</h2>
 108
 109                         <p>
 110                         </p><p>
 111                         I regularly use <i>rebase -i -p</i> these days, to update my personal Git
 112                         tree (which used to be <i>my-next</i>).
 113                         </p><p>
 114                         There are a few things missing before I can start assembling a patch
 115                         series for submission:
 116                         </p><p>
 117                         <ul>
 118                         <li>I need to handle the commit parents which are outside of the rebased
 119                         ones properly.  In other words, when a commit is picked whose parent is
 120                         not rebased, it needs to be rebased onto $ONTO.
 121                         <li>The patch which uses patch-id to generate DROPPED directly also tries to
 122                         consolidate the handling of DROPPED commits by putting them into REWRITTEN
 123                         instead of DROPPED, but that breaks the tests.  So, this patch needs to be
 124                         split.
 125                         <li>I want to introduce one more command, <i>rephrase</i>, which allows you to
 126                         modify the commit message, and nothing more, and <i>halt</i>, which does the
 127                         same as <i>edit</i> without <i>pick</i>.  Then there needs to be a new test script
 128                         for those commands, and this will be an early patch series.
 129                         <li>Time.  I need time, desperately.  If my day job was not as exciting as it
 130                         is, I would have more time for Git.  As it is, I have to budget my time so
 131                         that I get anything done at all.
 132                         </ul>
 133                         </p><p>
 134                         These issues have been postponed due to Steffen taking a well-deserved
 135                         vacation, which means that I have to act as msysGit maintainer again.
 136                         </p><p>
 137                         And this coming week, I will have other things to do in all likeliness, so
 138                         that I expect to be able to submit a <i>rebase -i -p</i> patch series only next
 139                         week.  If not then, due to a heavy workload, it will be postponed to early
 140                         April.
 141                         </p><p>
 142                         Oh well, the joys of being excited by several competing projects! &#x263a;
 143                         </p>
 144                         <h6>Sunday, 8th of March, Anno Domini MMIX, at the hour of the Tiger</h6>
 145                         <a name=1236479389>
 146                         <h2>New Git for Windows version</h2>
 147
 148                         <p>
 149                         </p><p>
 150                         Phew.  That was quite a day, almost exclusively spent on finishing that
 151                         installer.  The worst part: updating GCC seemed not to be such a good idea
 152                         after all...
 153                         </p><p>
 154                         For Windows, we need to use the printf format <i>%I64u</i> (which is
 155                         non-standard, in the common way of Microsoft) if you want to print 64-bit
 156                         wide unsigned numbers.  The rest of the world accepts the standard <i>%llu</i>.
 157                         </p><p>
 158                         After upgrading to the new GCC, a lot of warnings appeared, complaining
 159                         about <i>%I64u</i>.  The warnings went away when I replaced the format with
 160                         <i>%llu</i>.
 161                         </p><p>
 162                         Being the naive I am, I mistook that for a sign that we could finally go
 163                         more standards-compliant.
 164                         </p><p>
 165                         However, it only means that we have to live with the warnings for now, as
 166                         the C runtime provided on Windows still strongly disagrees with standards
 167                         (and it has to continue to do so, lest it break existing programs).
 168                         </p><p>
 169                         Sigh.
 170                         </p><p>
 171                         At least I have the feeling that I caught the most important bugs before
 172                         releasing.
 173                         </p>
 174                         <h6>Friday, 20th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 175                         <a name=1235092615>
 176                         <h2>Code reviews</h2>
 177
 178                         <p>
 179                         </p><p>
 180                         It has been said that reviewing patches is a most thankless job.  As I really
 181                         like the elegance of Git's source code, and care a lot about it, I did not
 182                         think that it was thankless, just a little bit tedious (especially when the
 183                         patch authors mistake criticism for personal attacks).
 184                         </p><p>
 185                         Usually, I am pretty good at ignoring insults as responses to my comments;
 186                         after all, I have a lot more enjoyable things to do than to spend time talking
 187                         to a guy who shows how wise he is when he thinks that I criticize him
 188                         <u>personally</u> when I just try to enhance his work, by offering a little bit of
 189                         my knowledge.
 190                         </p><p>
 191                         However, in the last days, three people really seemed to want to insult me,
 192                         to make me go away, to stop the fun I have with Git.
 193                         </p><p>
 194                         And they almost succeeded.
 195                         </p><p>
 196                         So I guess it is time to reassess my priorities, and maybe stop reviewing
 197                         Git patches altogether.
 198                         </p>
 199                         <h6>Thursday, 12th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 200                         <a name=1234409395>
 201                         <h2>Interactive <i>rebase</i> just learnt a new command: <i>topic</i></h2>
 202
 203                         <p>
 204                         </p><p>
 205                         Today I am pretty pleased with myself.  Two projects at my day job got a real
 206                         boost, and I implemented a shortcut that avoids the ugly 'bookmark' statement
 207                         in rebase scripts most of the time.
 208                         </p><p>
 209                         A typical rebase script, generated by <i>git rebase -i -p $COMMIT</i> will look
 210                         something like this:
 211                         </p><p>
 212                         <table
 213                                                         border=1 bgcolor=black>
 214                                                 <tr><td bgcolor=lightblue colspan=3>
 215                                 <pre>                                                                                </pre>
 216                         </td></tr>
 217                         <tr><td>
 218                                 <table cellspacing=5 border=0
 219                                          style="color:white;">
 220                                 <tr><td>
 221                                         <pre>
 222 pick 1234567 My first commit
 223 topic begin super-cool-feature
 224 pick 2345678 The super cool feature
 225 pick 3456789 Documentation for the super cool feature
 226 topic end super-cool-feature
 227 </pre>
 228                                                         </td></tr>
 229                                                         </table>
 230                                                 </td></tr>
 231                                                 </table>
 232                         </p><p>
 233                         The result will be a merge commit at the HEAD whose first parent is
 234                         "My first commit", whose second parent is "Documentation for the super
 235                         cool feature" and whose commit message is "Merge branch 'super-cool-feature'".
 236                         </p><p>
 237                         Side note: internally, <i>topic begin $NAME [at $COMMIT]</i> will be handled as if
 238                         you wrote <i>bookmark merge-parent-of-$NAME; goto $COMMIT</i>, and
 239                         <i>topic end $NAME [$MESSAGE]</i> will be handled as if you wrote
 240                         <i>bookmark $NAME; goto merge-parent-of-$NAME; merge parents $NAME [original $MARK Merge branch '$NAME']</i>.
 241                         </p><p>
 242                         Of course, being more concise, the 'topic' statement is not only nicer to the
 243                         eye, but also less error-prone.
 244                         </p><p>
 245                         And hopefully many people will agree with me that this rebase script is pretty
 246                         intuitive.
 247                         </p>
 248                         <h6>Wednesday, 11th of February, Anno Domini MMIX, at the hour of the Tiger</h6>
 249                         <a name=1234320806>
 250                         <h2>Thunderbird, oh Thunderbird, you always make my small brain hurt</h2>
 251
 252                         <p>
 253                         </p><p>
 254                         There was a lengthy discussion on the Git mailing list about using Thunderbird,
 255                         a not quite unpopular mailing program, to send inline patches.
 256                         </p><p>
 257                         It is really kind of sad that the Thunderbird developers do not see how
 258                         stubbornly they offend quite a number of people and scare them away from their
 259                         program.  After all, you should try to be liberal in what you accept and strict
 260                         in what you emit.  No, that does not mean that you should force others to
 261                         switch their mailers because you strictly adher to your philosophy in what you
 262                         emit, ignoring the rest of the world.
 263                         </p><p>
 264                         In any case, I am not affected (as long as I do not get mails from a poor soul
 265                         stuck with Thunderbird).
 266                         </p><p>
 267                         But I was a bit mean to that Thunderbird guy I dragged into the discussion, and
 268                         he seems really offended.
 269                         </p><p>
 270                         So I thought I'd give him a real reason to feel offended: I'll just do his work:
 271                         </p><p>
 272                         http://<a href=http://repo.or.cz>repo.or.cz</a>/w/UnFlowedThunderbird.git
 273                         </p><p>
 274                         It took my free time of two days, being not a Thunderbird developer myself.
 275                         Hopefully it works, and hopefully some people will feel really ashamed now.
 276                         </p>
 277                         <h6>Monday, 9th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 278                         <a name=1234141489>
 279                         <h2><i>format-patch --thread</i> and Alpine</h2>
 280
 281                         <p>
 282                         </p><p>
 283                         I started recently to pipe the output of
 284                         <i>git format-patch --cover-letter --stdout ...</i> directly into the
 285                         <i>postponed-msgs</i> folder Alpine uses, instead of pasting files into the
 286                         mailer.
 287                         </p><p>
 288                         The idea is to pretend that I continue a postponed mail, but in reality I
 289                         never wrote it, <i>format-patch</i> did.
 290                         </p><p>
 291                         However, I had problems with the <i>--thread</i> option that is implied by
 292                         <i>--cover-letter</i>.  Alpine always generated new message IDs without adjusting
 293                         the <i>In-reply-to:</i> and <i>References:</i> headers of the other mails.
 294                         </p><p>
 295                         Now I found out that the reason is that the <i>Fcc:</i> headers were missing in
 296                         the mails, and Alpine generated them, making up new message IDs in the process.
 297                         </p><p>
 298                         Therefore I have an alias now which sets not only the <i>Fcc:</i> header, but also
 299                         the <i>To:</i> headers by rewriting the stream using <i>sed</i>.  This is slightly
 300                         ugly, but so is the handling of headers in <i>format-patch</i>: if you thought
 301                         you could specify arbitrary headers using the command line, you are mistaken:
 302                         you can do that only by editing the config.
 303                         </p><p>
 304                         While at it, I also noticed a bug whereby <i>--thread --in-reply-to=...</i> simply
 305                         forgets the <i>--thread</i>.  Maybe this week I will find time to address this bug.
 306                         </p>
 307                         <h6>Monday, 9th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 308                         <a name=1234140696>
 309                         <h2><i>rebase</i> updates</h2>
 310
 311                         <p>
 312                         </p><p>
 313                         Phew.  The last few days, I was mainly chasing bugs I introduced due to being
 314                         too tired to work on the merge-preserving, interactive <i>rebase</i>.
 315                         </p><p>
 316                         But finally I have something I can start working with.  After my failed
 317                         experiment to use git-blame to split topic branches, I will sort the commits
 318                         in my <i>my-next</i> branch into topic branches manually.
 319                         </p><p>
 320                         Then I will add an option to <i>rebase -i -p</i> to rewrite refs which point to
 321                         rewritten commits, so that I can have branches <i>rebase-i-p</i>, <i>add-e</i>, etc
 322                         and all of them are automatically updated when I <i>rebase -i -p</i> the <i>my-next</i>
 323                         branch.
 324                         </p><p>
 325                         In the process, not only have I learnt the value of the <i>bookmark</i> command,
 326                         but made quite a few-much needed cleanups (which make
 327                         <i>git-rebase--interactive.sh</i> longer, but much more understandable).
 328                         </p><p>
 329                         Hopefully Stephan will pick the changes in the "rebase protocol" up, and then
 330                         we can have a sequencer with which I can start to make a graphical interactive
 331                         rebase using git-gui.  Or gitk.
 332                         </p><p>
 333                         Maybe.
 334                         </p>
 335                         <h6>Saturday, 7th of February, Anno Domini MMIX, at the hour of the Pig</h6>
 336                         <a name=1234040744>
 337                         <h2>The infamous <i>mark</i> command in the <i>rebase</i> command</h2>
 338
 339                         <p>
 340                         </p><p>
 341                         I realized today how easy it is to lose commits with the "merge preserving"
 342                         mode of the interactive rebase.  In my case, it was when I tried to move a
 343                         bunch of commits from the tip of my branch into a topic branch.
 344                         </p><p>
 345                         But after moving the commits, I forgot to update the parent of the merge
 346                         commit.  Possibly a mark command could have helped.  The very same command
 347                         I called a nightmare for usability.
 348                         </p><p>
 349                         So I was wrong.  Big news.  &#x263a;
 350                         </p><p>
 351                         However, I think that the syntax "mark :1" is something best left for
 352                         machine consumption, not for human beings.
 353                         </p><p>
 354                         But I have an idea: we could use some garbled commit subject, or in case of
 355                         merge parents, the merge subject as some human readable title of the mark.
 356                         </p><p>
 357                         The rebase script would then look something like this:
 358                         </p><p>
 359                         <table
 360                                                         border=1 bgcolor=black>
 361                                                 <tr><td bgcolor=lightblue colspan=3>
 362                                 <pre>                                                                                </pre>
 363                         </td></tr>
 364                         <tr><td>
 365                                 <table cellspacing=5 border=0
 366                                          style="color:white;">
 367                                 <tr><td>
 368                                         <pre>
 369 pick abcdefg Some ultra cool commit
 370 bookmark ultra-cool
 371 goto upstream
 372 pick hijklmn Some other cool commit
 373 merge parent ultra-cool Merge 'ultra-cool' into master
 374 </pre>
 375                                                         </td></tr>
 376                                                         </table>
 377                                                 </td></tr>
 378                                                 </table>
 379                         </p><p>
 380                         The good news is: I added code that refuses to finish a rebase when there
 381                         are commits that were rewritten, but not part of the new HEAD's ancestry.
 382                         </p>
 383                         <h6>Wednesday, 4th of February, Anno Domini MMIX, at the hour of the Buffalo</h6>
 384                         <a name=1233707628>
 385                         <h2>New valgrind series</h2>
 386
 387                         <p>
 388                         </p><p>
 389                         I spent quite some time cleaning up that patch series, and feel pretty
 390                         exhausted.
 391                         </p><p>
 392                         Granted, the new <i>git rebase -i -p</i> does its job without complaint so far
 393                         (so much so that I think I'll release a version of my <i>rebase</i> series
 394                         soonish), but it <u>is</u> a hassle when you have patches that you have a hard
 395                         time to decide upon the order/commit boundaries.
 396                         </p><p>
 397                         For example, I could imagine that the patch making the location of the
 398                         templates independent of the location of the Git binaries should come
 399                         <u>before</u> my patch series, and the valgrind specific part should then
 400                         be squashed into the first valgrind commit.
 401                         </p><p>
 402                         Also, it uses two features of valgrind 3.4.0:
 403                         </p><p>
 404                         <ul>
 405                         <li><i>...</i> in the suppression file, and
 406                         <li><i>--track-origins=yes</i>
 407                         </ul>
 408                         </p><p>
 409                         The latter is actually the reason I am pretty willing to keep the
 410                         requirement of that valgrind version, as it is really, really useful.
 411                         </p><p>
 412                         I guess we will see what happens to it.
 413                         </p>
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