Autogenerated HTML docs for v1.7.7-rc2-4-g5ec82
[git/jnareb-git.git] / howto / using-merge-subtree.html
blob97ec363f83dbb7ed4af2b96b15483d979630ddda
1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
2 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
4 <head>
5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
6 <meta name="generator" content="AsciiDoc 8.5.2" />
7 <title>How to use the subtree merge strategy</title>
8 <style type="text/css">
9 /* Debug borders */
10 p, li, dt, dd, div, pre, h1, h2, h3, h4, h5, h6 {
12 border: 1px solid red;
16 body {
17 margin: 1em 5% 1em 5%;
20 a {
21 color: blue;
22 text-decoration: underline;
24 a:visited {
25 color: fuchsia;
28 em {
29 font-style: italic;
30 color: navy;
33 strong {
34 font-weight: bold;
35 color: #083194;
38 tt {
39 color: navy;
42 h1, h2, h3, h4, h5, h6 {
43 color: #527bbd;
44 font-family: sans-serif;
45 margin-top: 1.2em;
46 margin-bottom: 0.5em;
47 line-height: 1.3;
50 h1, h2, h3 {
51 border-bottom: 2px solid silver;
53 h2 {
54 padding-top: 0.5em;
56 h3 {
57 float: left;
59 h3 + * {
60 clear: left;
63 div.sectionbody {
64 font-family: serif;
65 margin-left: 0;
68 hr {
69 border: 1px solid silver;
72 p {
73 margin-top: 0.5em;
74 margin-bottom: 0.5em;
77 ul, ol, li > p {
78 margin-top: 0;
81 pre {
82 padding: 0;
83 margin: 0;
86 span#author {
87 color: #527bbd;
88 font-family: sans-serif;
89 font-weight: bold;
90 font-size: 1.1em;
92 span#email {
94 span#revnumber, span#revdate, span#revremark {
95 font-family: sans-serif;
98 div#footer {
99 font-family: sans-serif;
100 font-size: small;
101 border-top: 2px solid silver;
102 padding-top: 0.5em;
103 margin-top: 4.0em;
105 div#footer-text {
106 float: left;
107 padding-bottom: 0.5em;
109 div#footer-badges {
110 float: right;
111 padding-bottom: 0.5em;
114 div#preamble {
115 margin-top: 1.5em;
116 margin-bottom: 1.5em;
118 div.tableblock, div.imageblock, div.exampleblock, div.verseblock,
119 div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
120 div.admonitionblock {
121 margin-top: 1.0em;
122 margin-bottom: 1.5em;
124 div.admonitionblock {
125 margin-top: 2.0em;
126 margin-bottom: 2.0em;
127 margin-right: 10%;
128 color: #606060;
131 div.content { /* Block element content. */
132 padding: 0;
135 /* Block element titles. */
136 div.title, caption.title {
137 color: #527bbd;
138 font-family: sans-serif;
139 font-weight: bold;
140 text-align: left;
141 margin-top: 1.0em;
142 margin-bottom: 0.5em;
144 div.title + * {
145 margin-top: 0;
148 td div.title:first-child {
149 margin-top: 0.0em;
151 div.content div.title:first-child {
152 margin-top: 0.0em;
154 div.content + div.title {
155 margin-top: 0.0em;
158 div.sidebarblock > div.content {
159 background: #ffffee;
160 border: 1px solid silver;
161 padding: 0.5em;
164 div.listingblock > div.content {
165 border: 1px solid silver;
166 background: #f4f4f4;
167 padding: 0.5em;
170 div.quoteblock, div.verseblock {
171 padding-left: 1.0em;
172 margin-left: 1.0em;
173 margin-right: 10%;
174 border-left: 5px solid #dddddd;
175 color: #777777;
178 div.quoteblock > div.attribution {
179 padding-top: 0.5em;
180 text-align: right;
183 div.verseblock > div.content {
184 white-space: pre;
186 div.verseblock > div.attribution {
187 padding-top: 0.75em;
188 text-align: left;
190 /* DEPRECATED: Pre version 8.2.7 verse style literal block. */
191 div.verseblock + div.attribution {
192 text-align: left;
195 div.admonitionblock .icon {
196 vertical-align: top;
197 font-size: 1.1em;
198 font-weight: bold;
199 text-decoration: underline;
200 color: #527bbd;
201 padding-right: 0.5em;
203 div.admonitionblock td.content {
204 padding-left: 0.5em;
205 border-left: 3px solid #dddddd;
208 div.exampleblock > div.content {
209 border-left: 3px solid #dddddd;
210 padding-left: 0.5em;
213 div.imageblock div.content { padding-left: 0; }
214 span.image img { border-style: none; }
215 a.image:visited { color: white; }
217 dl {
218 margin-top: 0.8em;
219 margin-bottom: 0.8em;
221 dt {
222 margin-top: 0.5em;
223 margin-bottom: 0;
224 font-style: normal;
225 color: navy;
227 dd > *:first-child {
228 margin-top: 0.1em;
231 ul, ol {
232 list-style-position: outside;
234 ol.arabic {
235 list-style-type: decimal;
237 ol.loweralpha {
238 list-style-type: lower-alpha;
240 ol.upperalpha {
241 list-style-type: upper-alpha;
243 ol.lowerroman {
244 list-style-type: lower-roman;
246 ol.upperroman {
247 list-style-type: upper-roman;
250 div.compact ul, div.compact ol,
251 div.compact p, div.compact p,
252 div.compact div, div.compact div {
253 margin-top: 0.1em;
254 margin-bottom: 0.1em;
257 div.tableblock > table {
258 border: 3px solid #527bbd;
260 thead, p.table.header {
261 font-family: sans-serif;
262 font-weight: bold;
264 tfoot {
265 font-weight: bold;
267 td > div.verse {
268 white-space: pre;
270 p.table {
271 margin-top: 0;
273 /* Because the table frame attribute is overriden by CSS in most browsers. */
274 div.tableblock > table[frame="void"] {
275 border-style: none;
277 div.tableblock > table[frame="hsides"] {
278 border-left-style: none;
279 border-right-style: none;
281 div.tableblock > table[frame="vsides"] {
282 border-top-style: none;
283 border-bottom-style: none;
287 div.hdlist {
288 margin-top: 0.8em;
289 margin-bottom: 0.8em;
291 div.hdlist tr {
292 padding-bottom: 15px;
294 dt.hdlist1.strong, td.hdlist1.strong {
295 font-weight: bold;
297 td.hdlist1 {
298 vertical-align: top;
299 font-style: normal;
300 padding-right: 0.8em;
301 color: navy;
303 td.hdlist2 {
304 vertical-align: top;
306 div.hdlist.compact tr {
307 margin: 0;
308 padding-bottom: 0;
311 .comment {
312 background: yellow;
315 .footnote, .footnoteref {
316 font-size: 0.8em;
319 span.footnote, span.footnoteref {
320 vertical-align: super;
323 #footnotes {
324 margin: 20px 0 20px 0;
325 padding: 7px 0 0 0;
328 #footnotes div.footnote {
329 margin: 0 0 5px 0;
332 #footnotes hr {
333 border: none;
334 border-top: 1px solid silver;
335 height: 1px;
336 text-align: left;
337 margin-left: 0;
338 width: 20%;
339 min-width: 100px;
343 @media print {
344 div#footer-badges { display: none; }
347 div#toc {
348 margin-bottom: 2.5em;
351 div#toctitle {
352 color: #527bbd;
353 font-family: sans-serif;
354 font-size: 1.1em;
355 font-weight: bold;
356 margin-top: 1.0em;
357 margin-bottom: 0.1em;
360 div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
361 margin-top: 0;
362 margin-bottom: 0;
364 div.toclevel2 {
365 margin-left: 2em;
366 font-size: 0.9em;
368 div.toclevel3 {
369 margin-left: 4em;
370 font-size: 0.9em;
372 div.toclevel4 {
373 margin-left: 6em;
374 font-size: 0.9em;
376 /* Workarounds for IE6's broken and incomplete CSS2. */
378 div.sidebar-content {
379 background: #ffffee;
380 border: 1px solid silver;
381 padding: 0.5em;
383 div.sidebar-title, div.image-title {
384 color: #527bbd;
385 font-family: sans-serif;
386 font-weight: bold;
387 margin-top: 0.0em;
388 margin-bottom: 0.5em;
391 div.listingblock div.content {
392 border: 1px solid silver;
393 background: #f4f4f4;
394 padding: 0.5em;
397 div.quoteblock-attribution {
398 padding-top: 0.5em;
399 text-align: right;
402 div.verseblock-content {
403 white-space: pre;
405 div.verseblock-attribution {
406 padding-top: 0.75em;
407 text-align: left;
410 div.exampleblock-content {
411 border-left: 3px solid #dddddd;
412 padding-left: 0.5em;
415 /* IE6 sets dynamically generated links as visited. */
416 div#toc a:visited { color: blue; }
417 </style>
418 <script type="text/javascript">
419 /*<![CDATA[*/
420 window.onload = function(){asciidoc.footnotes();}
421 var asciidoc = { // Namespace.
423 /////////////////////////////////////////////////////////////////////
424 // Table Of Contents generator
425 /////////////////////////////////////////////////////////////////////
427 /* Author: Mihai Bazon, September 2002
428 * http://students.infoiasi.ro/~mishoo
430 * Table Of Content generator
431 * Version: 0.4
433 * Feel free to use this script under the terms of the GNU General Public
434 * License, as long as you do not remove or alter this notice.
437 /* modified by Troy D. Hanson, September 2006. License: GPL */
438 /* modified by Stuart Rackham, 2006, 2009. License: GPL */
440 // toclevels = 1..4.
441 toc: function (toclevels) {
443 function getText(el) {
444 var text = "";
445 for (var i = el.firstChild; i != null; i = i.nextSibling) {
446 if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
447 text += i.data;
448 else if (i.firstChild != null)
449 text += getText(i);
451 return text;
454 function TocEntry(el, text, toclevel) {
455 this.element = el;
456 this.text = text;
457 this.toclevel = toclevel;
460 function tocEntries(el, toclevels) {
461 var result = new Array;
462 var re = new RegExp('[hH]([2-'+(toclevels+1)+'])');
463 // Function that scans the DOM tree for header elements (the DOM2
464 // nodeIterator API would be a better technique but not supported by all
465 // browsers).
466 var iterate = function (el) {
467 for (var i = el.firstChild; i != null; i = i.nextSibling) {
468 if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
469 var mo = re.exec(i.tagName);
470 if (mo && (i.getAttribute("class") || i.getAttribute("className")) != "float") {
471 result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
473 iterate(i);
477 iterate(el);
478 return result;
481 var toc = document.getElementById("toc");
482 var entries = tocEntries(document.getElementById("content"), toclevels);
483 for (var i = 0; i < entries.length; ++i) {
484 var entry = entries[i];
485 if (entry.element.id == "")
486 entry.element.id = "_toc_" + i;
487 var a = document.createElement("a");
488 a.href = "#" + entry.element.id;
489 a.appendChild(document.createTextNode(entry.text));
490 var div = document.createElement("div");
491 div.appendChild(a);
492 div.className = "toclevel" + entry.toclevel;
493 toc.appendChild(div);
495 if (entries.length == 0)
496 toc.parentNode.removeChild(toc);
500 /////////////////////////////////////////////////////////////////////
501 // Footnotes generator
502 /////////////////////////////////////////////////////////////////////
504 /* Based on footnote generation code from:
505 * http://www.brandspankingnew.net/archive/2005/07/format_footnote.html
508 footnotes: function () {
509 var cont = document.getElementById("content");
510 var noteholder = document.getElementById("footnotes");
511 var spans = cont.getElementsByTagName("span");
512 var refs = {};
513 var n = 0;
514 for (i=0; i<spans.length; i++) {
515 if (spans[i].className == "footnote") {
516 n++;
517 // Use [\s\S] in place of . so multi-line matches work.
518 // Because JavaScript has no s (dotall) regex flag.
519 note = spans[i].innerHTML.match(/\s*\[([\s\S]*)]\s*/)[1];
520 noteholder.innerHTML +=
521 "<div class='footnote' id='_footnote_" + n + "'>" +
522 "<a href='#_footnoteref_" + n + "' title='Return to text'>" +
523 n + "</a>. " + note + "</div>";
524 spans[i].innerHTML =
525 "[<a id='_footnoteref_" + n + "' href='#_footnote_" + n +
526 "' title='View footnote' class='footnote'>" + n + "</a>]";
527 var id =spans[i].getAttribute("id");
528 if (id != null) refs["#"+id] = n;
531 if (n == 0)
532 noteholder.parentNode.removeChild(noteholder);
533 else {
534 // Process footnoterefs.
535 for (i=0; i<spans.length; i++) {
536 if (spans[i].className == "footnoteref") {
537 var href = spans[i].getElementsByTagName("a")[0].getAttribute("href");
538 href = href.match(/#.*/)[0]; // Because IE return full URL.
539 n = refs[href];
540 spans[i].innerHTML =
541 "[<a href='#_footnote_" + n +
542 "' title='View footnote' class='footnote'>" + n + "</a>]";
549 /*]]>*/
550 </script>
551 </head>
552 <body>
553 <div id="header">
554 <h1>How to use the subtree merge strategy</h1>
555 </div>
556 <div id="content">
557 <div id="preamble">
558 <div class="sectionbody">
559 <div class="paragraph"><p>There are situations where you want to include contents in your project
560 from an independently developed project. You can just pull from the
561 other project as long as there are no conflicting paths.</p></div>
562 <div class="paragraph"><p>The problematic case is when there are conflicting files. Potential
563 candidates are Makefiles and other standard filenames. You could merge
564 these files but probably you do not want to. A better solution for this
565 problem can be to merge the project as its own subdirectory. This is not
566 supported by the <em>recursive</em> merge strategy, so just pulling won&#8217;t work.</p></div>
567 <div class="paragraph"><p>What you want is the <em>subtree</em> merge strategy, which helps you in such a
568 situation.</p></div>
569 <div class="paragraph"><p>In this example, let&#8217;s say you have the repository at <tt>/path/to/B</tt> (but
570 it can be an URL as well, if you want). You want to merge the <em>master</em>
571 branch of that repository to the <tt>dir-B</tt> subdirectory in your current
572 branch.</p></div>
573 <div class="paragraph"><p>Here is the command sequence you need:</p></div>
574 <div class="listingblock">
575 <div class="content">
576 <pre><tt>$ git remote add -f Bproject /path/to/B <b>&lt;1&gt;</b>
577 $ git merge -s ours --no-commit Bproject/master <b>&lt;2&gt;</b>
578 $ git read-tree --prefix=dir-B/ -u Bproject/master <b>&lt;3&gt;</b>
579 $ git commit -m "Merge B project as our subdirectory" <b>&lt;4&gt;</b>
581 $ git pull -s subtree Bproject master <b>&lt;5&gt;</b></tt></pre>
582 </div></div>
583 <div class="colist arabic"><ol>
584 <li>
586 name the other project "Bproject", and fetch.
587 </p>
588 </li>
589 <li>
591 prepare for the later step to record the result as a merge.
592 </p>
593 </li>
594 <li>
596 read "master" branch of Bproject to the subdirectory "dir-B".
597 </p>
598 </li>
599 <li>
601 record the merge result.
602 </p>
603 </li>
604 <li>
606 maintain the result with subsequent merges using "subtree"
607 </p>
608 </li>
609 </ol></div>
610 <div class="paragraph"><p>The first four commands are used for the initial merge, while the last
611 one is to merge updates from <em>B project</em>.</p></div>
612 </div>
613 </div>
614 <h2 id="_comparing_em_subtree_em_merge_with_submodules">Comparing <em>subtree</em> merge with submodules</h2>
615 <div class="sectionbody">
616 <div class="ulist"><ul>
617 <li>
619 The benefit of using subtree merge is that it requires less
620 administrative burden from the users of your repository. It works with
621 older (before Git v1.5.2) clients and you have the code right after
622 clone.
623 </p>
624 </li>
625 <li>
627 However if you use submodules then you can choose not to transfer the
628 submodule objects. This may be a problem with the subtree merge.
629 </p>
630 </li>
631 <li>
633 Also, in case you make changes to the other project, it is easier to
634 submit changes if you just use submodules.
635 </p>
636 </li>
637 </ul></div>
638 </div>
639 <h2 id="_additional_tips">Additional tips</h2>
640 <div class="sectionbody">
641 <div class="ulist"><ul>
642 <li>
644 If you made changes to the other project in your repository, they may
645 want to merge from your project. This is possible using subtree&#8201;&#8212;&#8201;it
646 can shift up the paths in your tree and then they can merge only the
647 relevant parts of your tree.
648 </p>
649 </li>
650 <li>
652 Please note that if the other project merges from you, then it will
653 connect its history to yours, which can be something they don&#8217;t want
655 </p>
656 </li>
657 </ul></div>
658 </div>
659 </div>
660 <div id="footnotes"><hr /></div>
661 <div id="footer">
662 <div id="footer-text">
663 Last updated 2011-09-21 23:17:57 PDT
664 </div>
665 </div>
666 </body>
667 </html>