Autogenerated HTML docs for v2.45.0-rc0-48-g10f128
[git-htmldocs.git] / howto / new-command.html
blob5a5e6c7fc619c1b2363090e6a884f1da5cf9e627
1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
3 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
4 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
5 <head>
6 <meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
7 <meta name="generator" content="AsciiDoc 10.2.0" />
8 <title>How to integrate new subcommands</title>
9 <style type="text/css">
10 /* Shared CSS for AsciiDoc xhtml11 and html5 backends */
12 /* Default font. */
13 body {
14 font-family: Georgia,serif;
17 /* Title font. */
18 h1, h2, h3, h4, h5, h6,
19 div.title, caption.title,
20 thead, p.table.header,
21 #toctitle,
22 #author, #revnumber, #revdate, #revremark,
23 #footer {
24 font-family: Arial,Helvetica,sans-serif;
27 body {
28 margin: 1em 5% 1em 5%;
31 a {
32 color: blue;
33 text-decoration: underline;
35 a:visited {
36 color: fuchsia;
39 em {
40 font-style: italic;
41 color: navy;
44 strong {
45 font-weight: bold;
46 color: #083194;
49 h1, h2, h3, h4, h5, h6 {
50 color: #527bbd;
51 margin-top: 1.2em;
52 margin-bottom: 0.5em;
53 line-height: 1.3;
56 h1, h2, h3 {
57 border-bottom: 2px solid silver;
59 h2 {
60 padding-top: 0.5em;
62 h3 {
63 float: left;
65 h3 + * {
66 clear: left;
68 h5 {
69 font-size: 1.0em;
72 div.sectionbody {
73 margin-left: 0;
76 hr {
77 border: 1px solid silver;
80 p {
81 margin-top: 0.5em;
82 margin-bottom: 0.5em;
85 ul, ol, li > p {
86 margin-top: 0;
88 ul > li { color: #aaa; }
89 ul > li > * { color: black; }
91 .monospaced, code, pre {
92 font-family: "Courier New", Courier, monospace;
93 font-size: inherit;
94 color: navy;
95 padding: 0;
96 margin: 0;
98 pre {
99 white-space: pre-wrap;
102 #author {
103 color: #527bbd;
104 font-weight: bold;
105 font-size: 1.1em;
107 #email {
109 #revnumber, #revdate, #revremark {
112 #footer {
113 font-size: small;
114 border-top: 2px solid silver;
115 padding-top: 0.5em;
116 margin-top: 4.0em;
118 #footer-text {
119 float: left;
120 padding-bottom: 0.5em;
122 #footer-badges {
123 float: right;
124 padding-bottom: 0.5em;
127 #preamble {
128 margin-top: 1.5em;
129 margin-bottom: 1.5em;
131 div.imageblock, div.exampleblock, div.verseblock,
132 div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
133 div.admonitionblock {
134 margin-top: 1.0em;
135 margin-bottom: 1.5em;
137 div.admonitionblock {
138 margin-top: 2.0em;
139 margin-bottom: 2.0em;
140 margin-right: 10%;
141 color: #606060;
144 div.content { /* Block element content. */
145 padding: 0;
148 /* Block element titles. */
149 div.title, caption.title {
150 color: #527bbd;
151 font-weight: bold;
152 text-align: left;
153 margin-top: 1.0em;
154 margin-bottom: 0.5em;
156 div.title + * {
157 margin-top: 0;
160 td div.title:first-child {
161 margin-top: 0.0em;
163 div.content div.title:first-child {
164 margin-top: 0.0em;
166 div.content + div.title {
167 margin-top: 0.0em;
170 div.sidebarblock > div.content {
171 background: #ffffee;
172 border: 1px solid #dddddd;
173 border-left: 4px solid #f0f0f0;
174 padding: 0.5em;
177 div.listingblock > div.content {
178 border: 1px solid #dddddd;
179 border-left: 5px solid #f0f0f0;
180 background: #f8f8f8;
181 padding: 0.5em;
184 div.quoteblock, div.verseblock {
185 padding-left: 1.0em;
186 margin-left: 1.0em;
187 margin-right: 10%;
188 border-left: 5px solid #f0f0f0;
189 color: #888;
192 div.quoteblock > div.attribution {
193 padding-top: 0.5em;
194 text-align: right;
197 div.verseblock > pre.content {
198 font-family: inherit;
199 font-size: inherit;
201 div.verseblock > div.attribution {
202 padding-top: 0.75em;
203 text-align: left;
205 /* DEPRECATED: Pre version 8.2.7 verse style literal block. */
206 div.verseblock + div.attribution {
207 text-align: left;
210 div.admonitionblock .icon {
211 vertical-align: top;
212 font-size: 1.1em;
213 font-weight: bold;
214 text-decoration: underline;
215 color: #527bbd;
216 padding-right: 0.5em;
218 div.admonitionblock td.content {
219 padding-left: 0.5em;
220 border-left: 3px solid #dddddd;
223 div.exampleblock > div.content {
224 border-left: 3px solid #dddddd;
225 padding-left: 0.5em;
228 div.imageblock div.content { padding-left: 0; }
229 span.image img { border-style: none; vertical-align: text-bottom; }
230 a.image:visited { color: white; }
232 dl {
233 margin-top: 0.8em;
234 margin-bottom: 0.8em;
236 dt {
237 margin-top: 0.5em;
238 margin-bottom: 0;
239 font-style: normal;
240 color: navy;
242 dd > *:first-child {
243 margin-top: 0.1em;
246 ul, ol {
247 list-style-position: outside;
249 ol.arabic {
250 list-style-type: decimal;
252 ol.loweralpha {
253 list-style-type: lower-alpha;
255 ol.upperalpha {
256 list-style-type: upper-alpha;
258 ol.lowerroman {
259 list-style-type: lower-roman;
261 ol.upperroman {
262 list-style-type: upper-roman;
265 div.compact ul, div.compact ol,
266 div.compact p, div.compact p,
267 div.compact div, div.compact div {
268 margin-top: 0.1em;
269 margin-bottom: 0.1em;
272 tfoot {
273 font-weight: bold;
275 td > div.verse {
276 white-space: pre;
279 div.hdlist {
280 margin-top: 0.8em;
281 margin-bottom: 0.8em;
283 div.hdlist tr {
284 padding-bottom: 15px;
286 dt.hdlist1.strong, td.hdlist1.strong {
287 font-weight: bold;
289 td.hdlist1 {
290 vertical-align: top;
291 font-style: normal;
292 padding-right: 0.8em;
293 color: navy;
295 td.hdlist2 {
296 vertical-align: top;
298 div.hdlist.compact tr {
299 margin: 0;
300 padding-bottom: 0;
303 .comment {
304 background: yellow;
307 .footnote, .footnoteref {
308 font-size: 0.8em;
311 span.footnote, span.footnoteref {
312 vertical-align: super;
315 #footnotes {
316 margin: 20px 0 20px 0;
317 padding: 7px 0 0 0;
320 #footnotes div.footnote {
321 margin: 0 0 5px 0;
324 #footnotes hr {
325 border: none;
326 border-top: 1px solid silver;
327 height: 1px;
328 text-align: left;
329 margin-left: 0;
330 width: 20%;
331 min-width: 100px;
334 div.colist td {
335 padding-right: 0.5em;
336 padding-bottom: 0.3em;
337 vertical-align: top;
339 div.colist td img {
340 margin-top: 0.3em;
343 @media print {
344 #footer-badges { display: none; }
347 #toc {
348 margin-bottom: 2.5em;
351 #toctitle {
352 color: #527bbd;
353 font-size: 1.1em;
354 font-weight: bold;
355 margin-top: 1.0em;
356 margin-bottom: 0.1em;
359 div.toclevel0, div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
360 margin-top: 0;
361 margin-bottom: 0;
363 div.toclevel2 {
364 margin-left: 2em;
365 font-size: 0.9em;
367 div.toclevel3 {
368 margin-left: 4em;
369 font-size: 0.9em;
371 div.toclevel4 {
372 margin-left: 6em;
373 font-size: 0.9em;
376 span.aqua { color: aqua; }
377 span.black { color: black; }
378 span.blue { color: blue; }
379 span.fuchsia { color: fuchsia; }
380 span.gray { color: gray; }
381 span.green { color: green; }
382 span.lime { color: lime; }
383 span.maroon { color: maroon; }
384 span.navy { color: navy; }
385 span.olive { color: olive; }
386 span.purple { color: purple; }
387 span.red { color: red; }
388 span.silver { color: silver; }
389 span.teal { color: teal; }
390 span.white { color: white; }
391 span.yellow { color: yellow; }
393 span.aqua-background { background: aqua; }
394 span.black-background { background: black; }
395 span.blue-background { background: blue; }
396 span.fuchsia-background { background: fuchsia; }
397 span.gray-background { background: gray; }
398 span.green-background { background: green; }
399 span.lime-background { background: lime; }
400 span.maroon-background { background: maroon; }
401 span.navy-background { background: navy; }
402 span.olive-background { background: olive; }
403 span.purple-background { background: purple; }
404 span.red-background { background: red; }
405 span.silver-background { background: silver; }
406 span.teal-background { background: teal; }
407 span.white-background { background: white; }
408 span.yellow-background { background: yellow; }
410 span.big { font-size: 2em; }
411 span.small { font-size: 0.6em; }
413 span.underline { text-decoration: underline; }
414 span.overline { text-decoration: overline; }
415 span.line-through { text-decoration: line-through; }
417 div.unbreakable { page-break-inside: avoid; }
421 * xhtml11 specific
423 * */
425 div.tableblock {
426 margin-top: 1.0em;
427 margin-bottom: 1.5em;
429 div.tableblock > table {
430 border: 3px solid #527bbd;
432 thead, p.table.header {
433 font-weight: bold;
434 color: #527bbd;
436 p.table {
437 margin-top: 0;
439 /* Because the table frame attribute is overridden by CSS in most browsers. */
440 div.tableblock > table[frame="void"] {
441 border-style: none;
443 div.tableblock > table[frame="hsides"] {
444 border-left-style: none;
445 border-right-style: none;
447 div.tableblock > table[frame="vsides"] {
448 border-top-style: none;
449 border-bottom-style: none;
454 * html5 specific
456 * */
458 table.tableblock {
459 margin-top: 1.0em;
460 margin-bottom: 1.5em;
462 thead, p.tableblock.header {
463 font-weight: bold;
464 color: #527bbd;
466 p.tableblock {
467 margin-top: 0;
469 table.tableblock {
470 border-width: 3px;
471 border-spacing: 0px;
472 border-style: solid;
473 border-color: #527bbd;
474 border-collapse: collapse;
476 th.tableblock, td.tableblock {
477 border-width: 1px;
478 padding: 4px;
479 border-style: solid;
480 border-color: #527bbd;
483 table.tableblock.frame-topbot {
484 border-left-style: hidden;
485 border-right-style: hidden;
487 table.tableblock.frame-sides {
488 border-top-style: hidden;
489 border-bottom-style: hidden;
491 table.tableblock.frame-none {
492 border-style: hidden;
495 th.tableblock.halign-left, td.tableblock.halign-left {
496 text-align: left;
498 th.tableblock.halign-center, td.tableblock.halign-center {
499 text-align: center;
501 th.tableblock.halign-right, td.tableblock.halign-right {
502 text-align: right;
505 th.tableblock.valign-top, td.tableblock.valign-top {
506 vertical-align: top;
508 th.tableblock.valign-middle, td.tableblock.valign-middle {
509 vertical-align: middle;
511 th.tableblock.valign-bottom, td.tableblock.valign-bottom {
512 vertical-align: bottom;
517 * manpage specific
519 * */
521 body.manpage h1 {
522 padding-top: 0.5em;
523 padding-bottom: 0.5em;
524 border-top: 2px solid silver;
525 border-bottom: 2px solid silver;
527 body.manpage h2 {
528 border-style: none;
530 body.manpage div.sectionbody {
531 margin-left: 3em;
534 @media print {
535 body.manpage div#toc { display: none; }
539 </style>
540 <script type="text/javascript">
541 /*<![CDATA[*/
542 var asciidoc = { // Namespace.
544 /////////////////////////////////////////////////////////////////////
545 // Table Of Contents generator
546 /////////////////////////////////////////////////////////////////////
548 /* Author: Mihai Bazon, September 2002
549 * http://students.infoiasi.ro/~mishoo
551 * Table Of Content generator
552 * Version: 0.4
554 * Feel free to use this script under the terms of the GNU General Public
555 * License, as long as you do not remove or alter this notice.
558 /* modified by Troy D. Hanson, September 2006. License: GPL */
559 /* modified by Stuart Rackham, 2006, 2009. License: GPL */
561 // toclevels = 1..4.
562 toc: function (toclevels) {
564 function getText(el) {
565 var text = "";
566 for (var i = el.firstChild; i != null; i = i.nextSibling) {
567 if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
568 text += i.data;
569 else if (i.firstChild != null)
570 text += getText(i);
572 return text;
575 function TocEntry(el, text, toclevel) {
576 this.element = el;
577 this.text = text;
578 this.toclevel = toclevel;
581 function tocEntries(el, toclevels) {
582 var result = new Array;
583 var re = new RegExp('[hH]([1-'+(toclevels+1)+'])');
584 // Function that scans the DOM tree for header elements (the DOM2
585 // nodeIterator API would be a better technique but not supported by all
586 // browsers).
587 var iterate = function (el) {
588 for (var i = el.firstChild; i != null; i = i.nextSibling) {
589 if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
590 var mo = re.exec(i.tagName);
591 if (mo && (i.getAttribute("class") || i.getAttribute("className")) != "float") {
592 result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
594 iterate(i);
598 iterate(el);
599 return result;
602 var toc = document.getElementById("toc");
603 if (!toc) {
604 return;
607 // Delete existing TOC entries in case we're reloading the TOC.
608 var tocEntriesToRemove = [];
609 var i;
610 for (i = 0; i < toc.childNodes.length; i++) {
611 var entry = toc.childNodes[i];
612 if (entry.nodeName.toLowerCase() == 'div'
613 && entry.getAttribute("class")
614 && entry.getAttribute("class").match(/^toclevel/))
615 tocEntriesToRemove.push(entry);
617 for (i = 0; i < tocEntriesToRemove.length; i++) {
618 toc.removeChild(tocEntriesToRemove[i]);
621 // Rebuild TOC entries.
622 var entries = tocEntries(document.getElementById("content"), toclevels);
623 for (var i = 0; i < entries.length; ++i) {
624 var entry = entries[i];
625 if (entry.element.id == "")
626 entry.element.id = "_toc_" + i;
627 var a = document.createElement("a");
628 a.href = "#" + entry.element.id;
629 a.appendChild(document.createTextNode(entry.text));
630 var div = document.createElement("div");
631 div.appendChild(a);
632 div.className = "toclevel" + entry.toclevel;
633 toc.appendChild(div);
635 if (entries.length == 0)
636 toc.parentNode.removeChild(toc);
640 /////////////////////////////////////////////////////////////////////
641 // Footnotes generator
642 /////////////////////////////////////////////////////////////////////
644 /* Based on footnote generation code from:
645 * http://www.brandspankingnew.net/archive/2005/07/format_footnote.html
648 footnotes: function () {
649 // Delete existing footnote entries in case we're reloading the footnodes.
650 var i;
651 var noteholder = document.getElementById("footnotes");
652 if (!noteholder) {
653 return;
655 var entriesToRemove = [];
656 for (i = 0; i < noteholder.childNodes.length; i++) {
657 var entry = noteholder.childNodes[i];
658 if (entry.nodeName.toLowerCase() == 'div' && entry.getAttribute("class") == "footnote")
659 entriesToRemove.push(entry);
661 for (i = 0; i < entriesToRemove.length; i++) {
662 noteholder.removeChild(entriesToRemove[i]);
665 // Rebuild footnote entries.
666 var cont = document.getElementById("content");
667 var spans = cont.getElementsByTagName("span");
668 var refs = {};
669 var n = 0;
670 for (i=0; i<spans.length; i++) {
671 if (spans[i].className == "footnote") {
672 n++;
673 var note = spans[i].getAttribute("data-note");
674 if (!note) {
675 // Use [\s\S] in place of . so multi-line matches work.
676 // Because JavaScript has no s (dotall) regex flag.
677 note = spans[i].innerHTML.match(/\s*\[([\s\S]*)]\s*/)[1];
678 spans[i].innerHTML =
679 "[<a id='_footnoteref_" + n + "' href='#_footnote_" + n +
680 "' title='View footnote' class='footnote'>" + n + "</a>]";
681 spans[i].setAttribute("data-note", note);
683 noteholder.innerHTML +=
684 "<div class='footnote' id='_footnote_" + n + "'>" +
685 "<a href='#_footnoteref_" + n + "' title='Return to text'>" +
686 n + "</a>. " + note + "</div>";
687 var id =spans[i].getAttribute("id");
688 if (id != null) refs["#"+id] = n;
691 if (n == 0)
692 noteholder.parentNode.removeChild(noteholder);
693 else {
694 // Process footnoterefs.
695 for (i=0; i<spans.length; i++) {
696 if (spans[i].className == "footnoteref") {
697 var href = spans[i].getElementsByTagName("a")[0].getAttribute("href");
698 href = href.match(/#.*/)[0]; // Because IE return full URL.
699 n = refs[href];
700 spans[i].innerHTML =
701 "[<a href='#_footnote_" + n +
702 "' title='View footnote' class='footnote'>" + n + "</a>]";
708 install: function(toclevels) {
709 var timerId;
711 function reinstall() {
712 asciidoc.footnotes();
713 if (toclevels) {
714 asciidoc.toc(toclevels);
718 function reinstallAndRemoveTimer() {
719 clearInterval(timerId);
720 reinstall();
723 timerId = setInterval(reinstall, 500);
724 if (document.addEventListener)
725 document.addEventListener("DOMContentLoaded", reinstallAndRemoveTimer, false);
726 else
727 window.onload = reinstallAndRemoveTimer;
731 asciidoc.install();
732 /*]]>*/
733 </script>
734 </head>
735 <body class="article">
736 <div id="header">
737 <h1>How to integrate new subcommands</h1>
738 <span id="revdate">2024-04-23</span>
739 </div>
740 <div id="content">
741 <div id="preamble">
742 <div class="sectionbody">
743 <div class="paragraph"><p>This is how-to documentation for people who want to add extension
744 commands to Git. It should be read alongside builtin.h.</p></div>
745 </div>
746 </div>
747 <div class="sect1">
748 <h2 id="_runtime_environment">Runtime environment</h2>
749 <div class="sectionbody">
750 <div class="paragraph"><p>Git subcommands are standalone executables that live in the Git exec
751 path, normally /usr/lib/git-core. The git executable itself is a
752 thin wrapper that knows where the subcommands live, and runs them by
753 passing command-line arguments to them.</p></div>
754 <div class="paragraph"><p>(If "git foo" is not found in the Git exec path, the wrapper
755 will look in the rest of your $PATH for it. Thus, it&#8217;s possible
756 to write local Git extensions that don&#8217;t live in system space.)</p></div>
757 </div>
758 </div>
759 <div class="sect1">
760 <h2 id="_implementation_languages">Implementation languages</h2>
761 <div class="sectionbody">
762 <div class="paragraph"><p>Most subcommands are written in C or shell. A few are written in
763 Perl.</p></div>
764 <div class="paragraph"><p>While we strongly encourage coding in portable C for portability,
765 these specific scripting languages are also acceptable. We won&#8217;t
766 accept more without a very strong technical case, as we don&#8217;t want
767 to broaden the Git suite&#8217;s required dependencies. Import utilities,
768 surgical tools, remote helpers and other code at the edges of the
769 Git suite are more lenient and we allow Python (and even Tcl/tk),
770 but they should not be used for core functions.</p></div>
771 <div class="paragraph"><p>This may change in the future. Especially Python is not allowed in
772 core because we need better Python integration in the Git Windows
773 installer before we can be confident people in that environment
774 won&#8217;t experience an unacceptably large loss of capability.</p></div>
775 <div class="paragraph"><p>C commands are normally written as single modules, named after the
776 command, that link a collection of functions called libgit. Thus,
777 your command <em>git-foo</em> would normally be implemented as a single
778 "git-foo.c" (or "builtin/foo.c" if it is to be linked to the main
779 binary); this organization makes it easy for people reading the code
780 to find things.</p></div>
781 <div class="paragraph"><p>See the CodingGuidelines document for other guidance on what we consider
782 good practice in C and shell, and api-builtin.txt for the support
783 functions available to built-in commands written in C.</p></div>
784 </div>
785 </div>
786 <div class="sect1">
787 <h2 id="_what_every_extension_command_needs">What every extension command needs</h2>
788 <div class="sectionbody">
789 <div class="paragraph"><p>You must have a man page, written in asciidoc (this is what Git help
790 followed by your subcommand name will display). Be aware that there is
791 a local asciidoc configuration and macros which you should use. It&#8217;s
792 often helpful to start by cloning an existing page and replacing the
793 text content.</p></div>
794 <div class="paragraph"><p>You must have a test, written to report in TAP (Test Anything Protocol).
795 Tests are executables (usually shell scripts) that live in the <em>t</em>
796 subdirectory of the tree. Each test name begins with <em>t</em> and a sequence
797 number that controls where in the test sequence it will be executed;
798 conventionally the rest of the name stem is that of the command
799 being tested.</p></div>
800 <div class="paragraph"><p>Read the file t/README to learn more about the conventions to be used
801 in writing tests, and the test support library.</p></div>
802 </div>
803 </div>
804 <div class="sect1">
805 <h2 id="_integrating_a_command">Integrating a command</h2>
806 <div class="sectionbody">
807 <div class="paragraph"><p>Here are the things you need to do when you want to merge a new
808 subcommand into the Git tree.</p></div>
809 <div class="olist arabic"><ol class="arabic">
810 <li>
812 Don&#8217;t forget to sign off your patch!
813 </p>
814 </li>
815 <li>
817 Append your command name to one of the variables BUILTIN_OBJS,
818 EXTRA_PROGRAMS, SCRIPT_SH, SCRIPT_PERL or SCRIPT_PYTHON.
819 </p>
820 </li>
821 <li>
823 Drop its test in the t directory.
824 </p>
825 </li>
826 <li>
828 If your command is implemented in an interpreted language with a
829 p-code intermediate form, make sure .gitignore in the main directory
830 includes a pattern entry that ignores such files. Python .pyc and
831 .pyo files will already be covered.
832 </p>
833 </li>
834 <li>
836 If your command has any dependency on a particular version of
837 your language, document it in the INSTALL file.
838 </p>
839 </li>
840 <li>
842 There is a file command-list.txt in the distribution main directory
843 that categorizes commands by type, so they can be listed in appropriate
844 subsections in the documentation&#8217;s summary command list. Add an entry
845 for yours. To understand the categories, look at command-list.txt
846 in the main directory. If the new command is part of the typical Git
847 workflow and you believe it common enough to be mentioned in <em>git help</em>,
848 map this command to a common group in the column [common].
849 </p>
850 </li>
851 <li>
853 Give the maintainer one paragraph to include in the RelNotes file
854 to describe the new feature; a good place to do so is in the cover
855 letter [PATCH 0/n].
856 </p>
857 </li>
858 </ol></div>
859 <div class="paragraph"><p>That&#8217;s all there is to it.</p></div>
860 </div>
861 </div>
862 </div>
863 <div id="footnotes"><hr /></div>
864 <div id="footer">
865 <div id="footer-text">
866 Last updated
867 2024-04-23 14:40:26 PDT
868 </div>
869 </div>
870 </body>
871 </html>