technical/shallow.html

   1 <!DOCTYPE html>
   2 <html xmlns="http://www.w3.org/1999/xhtml" lang="en">
   3 <head>
   4 <meta charset="UTF-8"/>
   5 <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
   6 <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
   7 <meta name="generator" content="Asciidoctor 2.0.20"/>
   8 <title>Shallow commits</title>
   9 <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700"/>
  10 <style>
  11 /*! Asciidoctor default stylesheet | MIT License | https://asciidoctor.org */
  12 /* Uncomment the following line when using as a custom stylesheet */
  13 /* @import "https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700"; */
  14 html{font-family:sans-serif;-webkit-text-size-adjust:100%}
  15 a{background:none}
  16 a:focus{outline:thin dotted}
  17 a:active,a:hover{outline:0}
  18 h1{font-size:2em;margin:.67em 0}
  19 b,strong{font-weight:bold}
  20 abbr{font-size:.9em}
  21 abbr[title]{cursor:help;border-bottom:1px dotted #dddddf;text-decoration:none}
  22 dfn{font-style:italic}
  23 hr{height:0}
  24 mark{background:#ff0;color:#000}
  25 code,kbd,pre,samp{font-family:monospace;font-size:1em}
  26 pre{white-space:pre-wrap}
  27 q{quotes:"\201C" "\201D" "\2018" "\2019"}
  28 small{font-size:80%}
  29 sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}
  30 sup{top:-.5em}
  31 sub{bottom:-.25em}
  32 img{border:0}
  33 svg:not(:root){overflow:hidden}
  34 figure{margin:0}
  35 audio,video{display:inline-block}
  36 audio:not([controls]){display:none;height:0}
  37 fieldset{border:1px solid silver;margin:0 2px;padding:.35em .625em .75em}
  38 legend{border:0;padding:0}
  39 button,input,select,textarea{font-family:inherit;font-size:100%;margin:0}
  40 button,input{line-height:normal}
  41 button,select{text-transform:none}
  42 button,html input[type=button],input[type=reset],input[type=submit]{-webkit-appearance:button;cursor:pointer}
  43 button[disabled],html input[disabled]{cursor:default}
  44 input[type=checkbox],input[type=radio]{padding:0}
  45 button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
  46 textarea{overflow:auto;vertical-align:top}
  47 table{border-collapse:collapse;border-spacing:0}
  48 *,::before,::after{box-sizing:border-box}
  49 html,body{font-size:100%}
  50 body{background:#fff;color:rgba(0,0,0,.8);padding:0;margin:0;font-family:"Noto Serif","DejaVu Serif",serif;line-height:1;position:relative;cursor:auto;-moz-tab-size:4;-o-tab-size:4;tab-size:4;word-wrap:anywhere;-moz-osx-font-smoothing:grayscale;-webkit-font-smoothing:antialiased}
  51 a:hover{cursor:pointer}
  52 img,object,embed{max-width:100%;height:auto}
  53 object,embed{height:100%}
  54 img{-ms-interpolation-mode:bicubic}
  55 .left{float:left!important}
  56 .right{float:right!important}
  57 .text-left{text-align:left!important}
  58 .text-right{text-align:right!important}
  59 .text-center{text-align:center!important}
  60 .text-justify{text-align:justify!important}
  61 .hide{display:none}
  62 img,object,svg{display:inline-block;vertical-align:middle}
  63 textarea{height:auto;min-height:50px}
  64 select{width:100%}
  65 .subheader,.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{line-height:1.45;color:#7a2518;font-weight:400;margin-top:0;margin-bottom:.25em}
  66 div,dl,dt,dd,ul,ol,li,h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6,pre,form,p,blockquote,th,td{margin:0;padding:0}
  67 a{color:#2156a5;text-decoration:underline;line-height:inherit}
  68 a:hover,a:focus{color:#1d4b8f}
  69 a img{border:0}
  70 p{line-height:1.6;margin-bottom:1.25em;text-rendering:optimizeLegibility}
  71 p aside{font-size:.875em;line-height:1.35;font-style:italic}
  72 h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{font-family:"Open Sans","DejaVu Sans",sans-serif;font-weight:300;font-style:normal;color:#ba3925;text-rendering:optimizeLegibility;margin-top:1em;margin-bottom:.5em;line-height:1.0125em}
  73 h1 small,h2 small,h3 small,#toctitle small,.sidebarblock>.content>.title small,h4 small,h5 small,h6 small{font-size:60%;color:#e99b8f;line-height:0}
  74 h1{font-size:2.125em}
  75 h2{font-size:1.6875em}
  76 h3,#toctitle,.sidebarblock>.content>.title{font-size:1.375em}
  77 h4,h5{font-size:1.125em}
  78 h6{font-size:1em}
  79 hr{border:solid #dddddf;border-width:1px 0 0;clear:both;margin:1.25em 0 1.1875em}
  80 em,i{font-style:italic;line-height:inherit}
  81 strong,b{font-weight:bold;line-height:inherit}
  82 small{font-size:60%;line-height:inherit}
  83 code{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;color:rgba(0,0,0,.9)}
  84 ul,ol,dl{line-height:1.6;margin-bottom:1.25em;list-style-position:outside;font-family:inherit}
  85 ul,ol{margin-left:1.5em}
  86 ul li ul,ul li ol{margin-left:1.25em;margin-bottom:0}
  87 ul.circle{list-style-type:circle}
  88 ul.disc{list-style-type:disc}
  89 ul.square{list-style-type:square}
  90 ul.circle ul:not([class]),ul.disc ul:not([class]),ul.square ul:not([class]){list-style:inherit}
  91 ol li ul,ol li ol{margin-left:1.25em;margin-bottom:0}
  92 dl dt{margin-bottom:.3125em;font-weight:bold}
  93 dl dd{margin-bottom:1.25em}
  94 blockquote{margin:0 0 1.25em;padding:.5625em 1.25em 0 1.1875em;border-left:1px solid #ddd}
  95 blockquote,blockquote p{line-height:1.6;color:rgba(0,0,0,.85)}
  96 @media screen and (min-width:768px){h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2}
  97 h1{font-size:2.75em}
  98 h2{font-size:2.3125em}
  99 h3,#toctitle,.sidebarblock>.content>.title{font-size:1.6875em}
 100 h4{font-size:1.4375em}}
 101 table{background:#fff;margin-bottom:1.25em;border:1px solid #dedede;word-wrap:normal}
 102 table thead,table tfoot{background:#f7f8f7}
 103 table thead tr th,table thead tr td,table tfoot tr th,table tfoot tr td{padding:.5em .625em .625em;font-size:inherit;color:rgba(0,0,0,.8);text-align:left}
 104 table tr th,table tr td{padding:.5625em .625em;font-size:inherit;color:rgba(0,0,0,.8)}
 105 table tr.even,table tr.alt{background:#f8f8f7}
 106 table thead tr th,table tfoot tr th,table tbody tr td,table tr td,table tfoot tr td{line-height:1.6}
 107 h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2;word-spacing:-.05em}
 108 h1 strong,h2 strong,h3 strong,#toctitle strong,.sidebarblock>.content>.title strong,h4 strong,h5 strong,h6 strong{font-weight:400}
 109 .center{margin-left:auto;margin-right:auto}
 110 .stretch{width:100%}
 111 .clearfix::before,.clearfix::after,.float-group::before,.float-group::after{content:" ";display:table}
 112 .clearfix::after,.float-group::after{clear:both}
 113 :not(pre).nobreak{word-wrap:normal}
 114 :not(pre).nowrap{white-space:nowrap}
 115 :not(pre).pre-wrap{white-space:pre-wrap}
 116 :not(pre):not([class^=L])>code{font-size:.9375em;font-style:normal!important;letter-spacing:0;padding:.1em .5ex;word-spacing:-.15em;background:#f7f7f8;border-radius:4px;line-height:1.45;text-rendering:optimizeSpeed}
 117 pre{color:rgba(0,0,0,.9);font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;line-height:1.45;text-rendering:optimizeSpeed}
 118 pre code,pre pre{color:inherit;font-size:inherit;line-height:inherit}
 119 pre>code{display:block}
 120 pre.nowrap,pre.nowrap pre{white-space:pre;word-wrap:normal}
 121 em em{font-style:normal}
 122 strong strong{font-weight:400}
 123 .keyseq{color:rgba(51,51,51,.8)}
 124 kbd{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;display:inline-block;color:rgba(0,0,0,.8);font-size:.65em;line-height:1.45;background:#f7f7f7;border:1px solid #ccc;border-radius:3px;box-shadow:0 1px 0 rgba(0,0,0,.2),inset 0 0 0 .1em #fff;margin:0 .15em;padding:.2em .5em;vertical-align:middle;position:relative;top:-.1em;white-space:nowrap}
 125 .keyseq kbd:first-child{margin-left:0}
 126 .keyseq kbd:last-child{margin-right:0}
 127 .menuseq,.menuref{color:#000}
 128 .menuseq b:not(.caret),.menuref{font-weight:inherit}
 129 .menuseq{word-spacing:-.02em}
 130 .menuseq b.caret{font-size:1.25em;line-height:.8}
 131 .menuseq i.caret{font-weight:bold;text-align:center;width:.45em}
 132 b.button::before,b.button::after{position:relative;top:-1px;font-weight:400}
 133 b.button::before{content:"[";padding:0 3px 0 2px}
 134 b.button::after{content:"]";padding:0 2px 0 3px}
 135 p a>code:hover{color:rgba(0,0,0,.9)}
 136 #header,#content,#footnotes,#footer{width:100%;margin:0 auto;max-width:62.5em;*zoom:1;position:relative;padding-left:.9375em;padding-right:.9375em}
 137 #header::before,#header::after,#content::before,#content::after,#footnotes::before,#footnotes::after,#footer::before,#footer::after{content:" ";display:table}
 138 #header::after,#content::after,#footnotes::after,#footer::after{clear:both}
 139 #content{margin-top:1.25em}
 140 #content::before{content:none}
 141 #header>h1:first-child{color:rgba(0,0,0,.85);margin-top:2.25rem;margin-bottom:0}
 142 #header>h1:first-child+#toc{margin-top:8px;border-top:1px solid #dddddf}
 143 #header>h1:only-child,body.toc2 #header>h1:nth-last-child(2){border-bottom:1px solid #dddddf;padding-bottom:8px}
 144 #header .details{border-bottom:1px solid #dddddf;line-height:1.45;padding-top:.25em;padding-bottom:.25em;padding-left:.25em;color:rgba(0,0,0,.6);display:flex;flex-flow:row wrap}
 145 #header .details span:first-child{margin-left:-.125em}
 146 #header .details span.email a{color:rgba(0,0,0,.85)}
 147 #header .details br{display:none}
 148 #header .details br+span::before{content:"\00a0\2013\00a0"}
 149 #header .details br+span.author::before{content:"\00a0\22c5\00a0";color:rgba(0,0,0,.85)}
 150 #header .details br+span#revremark::before{content:"\00a0|\00a0"}
 151 #header #revnumber{text-transform:capitalize}
 152 #header #revnumber::after{content:"\00a0"}
 153 #content>h1:first-child:not([class]){color:rgba(0,0,0,.85);border-bottom:1px solid #dddddf;padding-bottom:8px;margin-top:0;padding-top:1rem;margin-bottom:1.25rem}
 154 #toc{border-bottom:1px solid #e7e7e9;padding-bottom:.5em}
 155 #toc>ul{margin-left:.125em}
 156 #toc ul.sectlevel0>li>a{font-style:italic}
 157 #toc ul.sectlevel0 ul.sectlevel1{margin:.5em 0}
 158 #toc ul{font-family:"Open Sans","DejaVu Sans",sans-serif;list-style-type:none}
 159 #toc li{line-height:1.3334;margin-top:.3334em}
 160 #toc a{text-decoration:none}
 161 #toc a:active{text-decoration:underline}
 162 #toctitle{color:#7a2518;font-size:1.2em}
 163 @media screen and (min-width:768px){#toctitle{font-size:1.375em}
 164 body.toc2{padding-left:15em;padding-right:0}
 165 #toc.toc2{margin-top:0!important;background:#f8f8f7;position:fixed;width:15em;left:0;top:0;border-right:1px solid #e7e7e9;border-top-width:0!important;border-bottom-width:0!important;z-index:1000;padding:1.25em 1em;height:100%;overflow:auto}
 166 #toc.toc2 #toctitle{margin-top:0;margin-bottom:.8rem;font-size:1.2em}
 167 #toc.toc2>ul{font-size:.9em;margin-bottom:0}
 168 #toc.toc2 ul ul{margin-left:0;padding-left:1em}
 169 #toc.toc2 ul.sectlevel0 ul.sectlevel1{padding-left:0;margin-top:.5em;margin-bottom:.5em}
 170 body.toc2.toc-right{padding-left:0;padding-right:15em}
 171 body.toc2.toc-right #toc.toc2{border-right-width:0;border-left:1px solid #e7e7e9;left:auto;right:0}}
 172 @media screen and (min-width:1280px){body.toc2{padding-left:20em;padding-right:0}
 173 #toc.toc2{width:20em}
 174 #toc.toc2 #toctitle{font-size:1.375em}
 175 #toc.toc2>ul{font-size:.95em}
 176 #toc.toc2 ul ul{padding-left:1.25em}
 177 body.toc2.toc-right{padding-left:0;padding-right:20em}}
 178 #content #toc{border:1px solid #e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;border-radius:4px}
 179 #content #toc>:first-child{margin-top:0}
 180 #content #toc>:last-child{margin-bottom:0}
 181 #footer{max-width:none;background:rgba(0,0,0,.8);padding:1.25em}
 182 #footer-text{color:hsla(0,0%,100%,.8);line-height:1.44}
 183 #content{margin-bottom:.625em}
 184 .sect1{padding-bottom:.625em}
 185 @media screen and (min-width:768px){#content{margin-bottom:1.25em}
 186 .sect1{padding-bottom:1.25em}}
 187 .sect1:last-child{padding-bottom:0}
 188 .sect1+.sect1{border-top:1px solid #e7e7e9}
 189 #content h1>a.anchor,h2>a.anchor,h3>a.anchor,#toctitle>a.anchor,.sidebarblock>.content>.title>a.anchor,h4>a.anchor,h5>a.anchor,h6>a.anchor{position:absolute;z-index:1001;width:1.5ex;margin-left:-1.5ex;display:block;text-decoration:none!important;visibility:hidden;text-align:center;font-weight:400}
 190 #content h1>a.anchor::before,h2>a.anchor::before,h3>a.anchor::before,#toctitle>a.anchor::before,.sidebarblock>.content>.title>a.anchor::before,h4>a.anchor::before,h5>a.anchor::before,h6>a.anchor::before{content:"\00A7";font-size:.85em;display:block;padding-top:.1em}
 191 #content h1:hover>a.anchor,#content h1>a.anchor:hover,h2:hover>a.anchor,h2>a.anchor:hover,h3:hover>a.anchor,#toctitle:hover>a.anchor,.sidebarblock>.content>.title:hover>a.anchor,h3>a.anchor:hover,#toctitle>a.anchor:hover,.sidebarblock>.content>.title>a.anchor:hover,h4:hover>a.anchor,h4>a.anchor:hover,h5:hover>a.anchor,h5>a.anchor:hover,h6:hover>a.anchor,h6>a.anchor:hover{visibility:visible}
 192 #content h1>a.link,h2>a.link,h3>a.link,#toctitle>a.link,.sidebarblock>.content>.title>a.link,h4>a.link,h5>a.link,h6>a.link{color:#ba3925;text-decoration:none}
 193 #content h1>a.link:hover,h2>a.link:hover,h3>a.link:hover,#toctitle>a.link:hover,.sidebarblock>.content>.title>a.link:hover,h4>a.link:hover,h5>a.link:hover,h6>a.link:hover{color:#a53221}
 194 details,.audioblock,.imageblock,.literalblock,.listingblock,.stemblock,.videoblock{margin-bottom:1.25em}
 195 details{margin-left:1.25rem}
 196 details>summary{cursor:pointer;display:block;position:relative;line-height:1.6;margin-bottom:.625rem;outline:none;-webkit-tap-highlight-color:transparent}
 197 details>summary::-webkit-details-marker{display:none}
 198 details>summary::before{content:"";border:solid transparent;border-left:solid;border-width:.3em 0 .3em .5em;position:absolute;top:.5em;left:-1.25rem;transform:translateX(15%)}
 199 details[open]>summary::before{border:solid transparent;border-top:solid;border-width:.5em .3em 0;transform:translateY(15%)}
 200 details>summary::after{content:"";width:1.25rem;height:1em;position:absolute;top:.3em;left:-1.25rem}
 201 .admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{text-rendering:optimizeLegibility;text-align:left;font-family:"Noto Serif","DejaVu Serif",serif;font-size:1rem;font-style:italic}
 202 table.tableblock.fit-content>caption.title{white-space:nowrap;width:0}
 203 .paragraph.lead>p,#preamble>.sectionbody>[class=paragraph]:first-of-type p{font-size:1.21875em;line-height:1.6;color:rgba(0,0,0,.85)}
 204 .admonitionblock>table{border-collapse:separate;border:0;background:none;width:100%}
 205 .admonitionblock>table td.icon{text-align:center;width:80px}
 206 .admonitionblock>table td.icon img{max-width:none}
 207 .admonitionblock>table td.icon .title{font-weight:bold;font-family:"Open Sans","DejaVu Sans",sans-serif;text-transform:uppercase}
 208 .admonitionblock>table td.content{padding-left:1.125em;padding-right:1.25em;border-left:1px solid #dddddf;color:rgba(0,0,0,.6);word-wrap:anywhere}
 209 .admonitionblock>table td.content>:last-child>:last-child{margin-bottom:0}
 210 .exampleblock>.content{border:1px solid #e6e6e6;margin-bottom:1.25em;padding:1.25em;background:#fff;border-radius:4px}
 211 .sidebarblock{border:1px solid #dbdbd6;margin-bottom:1.25em;padding:1.25em;background:#f3f3f2;border-radius:4px}
 212 .sidebarblock>.content>.title{color:#7a2518;margin-top:0;text-align:center}
 213 .exampleblock>.content>:first-child,.sidebarblock>.content>:first-child{margin-top:0}
 214 .exampleblock>.content>:last-child,.exampleblock>.content>:last-child>:last-child,.exampleblock>.content .olist>ol>li:last-child>:last-child,.exampleblock>.content .ulist>ul>li:last-child>:last-child,.exampleblock>.content .qlist>ol>li:last-child>:last-child,.sidebarblock>.content>:last-child,.sidebarblock>.content>:last-child>:last-child,.sidebarblock>.content .olist>ol>li:last-child>:last-child,.sidebarblock>.content .ulist>ul>li:last-child>:last-child,.sidebarblock>.content .qlist>ol>li:last-child>:last-child{margin-bottom:0}
 215 .literalblock pre,.listingblock>.content>pre{border-radius:4px;overflow-x:auto;padding:1em;font-size:.8125em}
 216 @media screen and (min-width:768px){.literalblock pre,.listingblock>.content>pre{font-size:.90625em}}
 217 @media screen and (min-width:1280px){.literalblock pre,.listingblock>.content>pre{font-size:1em}}
 218 .literalblock pre,.listingblock>.content>pre:not(.highlight),.listingblock>.content>pre[class=highlight],.listingblock>.content>pre[class^="highlight "]{background:#f7f7f8}
 219 .literalblock.output pre{color:#f7f7f8;background:rgba(0,0,0,.9)}
 220 .listingblock>.content{position:relative}
 221 .listingblock code[data-lang]::before{display:none;content:attr(data-lang);position:absolute;font-size:.75em;top:.425rem;right:.5rem;line-height:1;text-transform:uppercase;color:inherit;opacity:.5}
 222 .listingblock:hover code[data-lang]::before{display:block}
 223 .listingblock.terminal pre .command::before{content:attr(data-prompt);padding-right:.5em;color:inherit;opacity:.5}
 224 .listingblock.terminal pre .command:not([data-prompt])::before{content:"$"}
 225 .listingblock pre.highlightjs{padding:0}
 226 .listingblock pre.highlightjs>code{padding:1em;border-radius:4px}
 227 .listingblock pre.prettyprint{border-width:0}
 228 .prettyprint{background:#f7f7f8}
 229 pre.prettyprint .linenums{line-height:1.45;margin-left:2em}
 230 pre.prettyprint li{background:none;list-style-type:inherit;padding-left:0}
 231 pre.prettyprint li code[data-lang]::before{opacity:1}
 232 pre.prettyprint li:not(:first-child) code[data-lang]::before{display:none}
 233 table.linenotable{border-collapse:separate;border:0;margin-bottom:0;background:none}
 234 table.linenotable td[class]{color:inherit;vertical-align:top;padding:0;line-height:inherit;white-space:normal}
 235 table.linenotable td.code{padding-left:.75em}
 236 table.linenotable td.linenos,pre.pygments .linenos{border-right:1px solid;opacity:.35;padding-right:.5em;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none}
 237 pre.pygments span.linenos{display:inline-block;margin-right:.75em}
 238 .quoteblock{margin:0 1em 1.25em 1.5em;display:table}
 239 .quoteblock:not(.excerpt)>.title{margin-left:-1.5em;margin-bottom:.75em}
 240 .quoteblock blockquote,.quoteblock p{color:rgba(0,0,0,.85);font-size:1.15rem;line-height:1.75;word-spacing:.1em;letter-spacing:0;font-style:italic;text-align:justify}
 241 .quoteblock blockquote{margin:0;padding:0;border:0}
 242 .quoteblock blockquote::before{content:"\201c";float:left;font-size:2.75em;font-weight:bold;line-height:.6em;margin-left:-.6em;color:#7a2518;text-shadow:0 1px 2px rgba(0,0,0,.1)}
 243 .quoteblock blockquote>.paragraph:last-child p{margin-bottom:0}
 244 .quoteblock .attribution{margin-top:.75em;margin-right:.5ex;text-align:right}
 245 .verseblock{margin:0 1em 1.25em}
 246 .verseblock pre{font-family:"Open Sans","DejaVu Sans",sans-serif;font-size:1.15rem;color:rgba(0,0,0,.85);font-weight:300;text-rendering:optimizeLegibility}
 247 .verseblock pre strong{font-weight:400}
 248 .verseblock .attribution{margin-top:1.25rem;margin-left:.5ex}
 249 .quoteblock .attribution,.verseblock .attribution{font-size:.9375em;line-height:1.45;font-style:italic}
 250 .quoteblock .attribution br,.verseblock .attribution br{display:none}
 251 .quoteblock .attribution cite,.verseblock .attribution cite{display:block;letter-spacing:-.025em;color:rgba(0,0,0,.6)}
 252 .quoteblock.abstract blockquote::before,.quoteblock.excerpt blockquote::before,.quoteblock .quoteblock blockquote::before{display:none}
 253 .quoteblock.abstract blockquote,.quoteblock.abstract p,.quoteblock.excerpt blockquote,.quoteblock.excerpt p,.quoteblock .quoteblock blockquote,.quoteblock .quoteblock p{line-height:1.6;word-spacing:0}
 254 .quoteblock.abstract{margin:0 1em 1.25em;display:block}
 255 .quoteblock.abstract>.title{margin:0 0 .375em;font-size:1.15em;text-align:center}
 256 .quoteblock.excerpt>blockquote,.quoteblock .quoteblock{padding:0 0 .25em 1em;border-left:.25em solid #dddddf}
 257 .quoteblock.excerpt,.quoteblock .quoteblock{margin-left:0}
 258 .quoteblock.excerpt blockquote,.quoteblock.excerpt p,.quoteblock .quoteblock blockquote,.quoteblock .quoteblock p{color:inherit;font-size:1.0625rem}
 259 .quoteblock.excerpt .attribution,.quoteblock .quoteblock .attribution{color:inherit;font-size:.85rem;text-align:left;margin-right:0}
 260 p.tableblock:last-child{margin-bottom:0}
 261 td.tableblock>.content{margin-bottom:1.25em;word-wrap:anywhere}
 262 td.tableblock>.content>:last-child{margin-bottom:-1.25em}
 263 table.tableblock,th.tableblock,td.tableblock{border:0 solid #dedede}
 264 table.grid-all>*>tr>*{border-width:1px}
 265 table.grid-cols>*>tr>*{border-width:0 1px}
 266 table.grid-rows>*>tr>*{border-width:1px 0}
 267 table.frame-all{border-width:1px}
 268 table.frame-ends{border-width:1px 0}
 269 table.frame-sides{border-width:0 1px}
 270 table.frame-none>colgroup+*>:first-child>*,table.frame-sides>colgroup+*>:first-child>*{border-top-width:0}
 271 table.frame-none>:last-child>:last-child>*,table.frame-sides>:last-child>:last-child>*{border-bottom-width:0}
 272 table.frame-none>*>tr>:first-child,table.frame-ends>*>tr>:first-child{border-left-width:0}
 273 table.frame-none>*>tr>:last-child,table.frame-ends>*>tr>:last-child{border-right-width:0}
 274 table.stripes-all>*>tr,table.stripes-odd>*>tr:nth-of-type(odd),table.stripes-even>*>tr:nth-of-type(even),table.stripes-hover>*>tr:hover{background:#f8f8f7}
 275 th.halign-left,td.halign-left{text-align:left}
 276 th.halign-right,td.halign-right{text-align:right}
 277 th.halign-center,td.halign-center{text-align:center}
 278 th.valign-top,td.valign-top{vertical-align:top}
 279 th.valign-bottom,td.valign-bottom{vertical-align:bottom}
 280 th.valign-middle,td.valign-middle{vertical-align:middle}
 281 table thead th,table tfoot th{font-weight:bold}
 282 tbody tr th{background:#f7f8f7}
 283 tbody tr th,tbody tr th p,tfoot tr th,tfoot tr th p{color:rgba(0,0,0,.8);font-weight:bold}
 284 p.tableblock>code:only-child{background:none;padding:0}
 285 p.tableblock{font-size:1em}
 286 ol{margin-left:1.75em}
 287 ul li ol{margin-left:1.5em}
 288 dl dd{margin-left:1.125em}
 289 dl dd:last-child,dl dd:last-child>:last-child{margin-bottom:0}
 290 li p,ul dd,ol dd,.olist .olist,.ulist .ulist,.ulist .olist,.olist .ulist{margin-bottom:.625em}
 291 ul.checklist,ul.none,ol.none,ul.no-bullet,ol.no-bullet,ol.unnumbered,ul.unstyled,ol.unstyled{list-style-type:none}
 292 ul.no-bullet,ol.no-bullet,ol.unnumbered{margin-left:.625em}
 293 ul.unstyled,ol.unstyled{margin-left:0}
 294 li>p:empty:only-child::before{content:"";display:inline-block}
 295 ul.checklist>li>p:first-child{margin-left:-1em}
 296 ul.checklist>li>p:first-child>.fa-square-o:first-child,ul.checklist>li>p:first-child>.fa-check-square-o:first-child{width:1.25em;font-size:.8em;position:relative;bottom:.125em}
 297 ul.checklist>li>p:first-child>input[type=checkbox]:first-child{margin-right:.25em}
 298 ul.inline{display:flex;flex-flow:row wrap;list-style:none;margin:0 0 .625em -1.25em}
 299 ul.inline>li{margin-left:1.25em}
 300 .unstyled dl dt{font-weight:400;font-style:normal}
 301 ol.arabic{list-style-type:decimal}
 302 ol.decimal{list-style-type:decimal-leading-zero}
 303 ol.loweralpha{list-style-type:lower-alpha}
 304 ol.upperalpha{list-style-type:upper-alpha}
 305 ol.lowerroman{list-style-type:lower-roman}
 306 ol.upperroman{list-style-type:upper-roman}
 307 ol.lowergreek{list-style-type:lower-greek}
 308 .hdlist>table,.colist>table{border:0;background:none}
 309 .hdlist>table>tbody>tr,.colist>table>tbody>tr{background:none}
 310 td.hdlist1,td.hdlist2{vertical-align:top;padding:0 .625em}
 311 td.hdlist1{font-weight:bold;padding-bottom:1.25em}
 312 td.hdlist2{word-wrap:anywhere}
 313 .literalblock+.colist,.listingblock+.colist{margin-top:-.5em}
 314 .colist td:not([class]):first-child{padding:.4em .75em 0;line-height:1;vertical-align:top}
 315 .colist td:not([class]):first-child img{max-width:none}
 316 .colist td:not([class]):last-child{padding:.25em 0}
 317 .thumb,.th{line-height:0;display:inline-block;border:4px solid #fff;box-shadow:0 0 0 1px #ddd}
 318 .imageblock.left{margin:.25em .625em 1.25em 0}
 319 .imageblock.right{margin:.25em 0 1.25em .625em}
 320 .imageblock>.title{margin-bottom:0}
 321 .imageblock.thumb,.imageblock.th{border-width:6px}
 322 .imageblock.thumb>.title,.imageblock.th>.title{padding:0 .125em}
 323 .image.left,.image.right{margin-top:.25em;margin-bottom:.25em;display:inline-block;line-height:0}
 324 .image.left{margin-right:.625em}
 325 .image.right{margin-left:.625em}
 326 a.image{text-decoration:none;display:inline-block}
 327 a.image object{pointer-events:none}
 328 sup.footnote,sup.footnoteref{font-size:.875em;position:static;vertical-align:super}
 329 sup.footnote a,sup.footnoteref a{text-decoration:none}
 330 sup.footnote a:active,sup.footnoteref a:active{text-decoration:underline}
 331 #footnotes{padding-top:.75em;padding-bottom:.75em;margin-bottom:.625em}
 332 #footnotes hr{width:20%;min-width:6.25em;margin:-.25em 0 .75em;border-width:1px 0 0}
 333 #footnotes .footnote{padding:0 .375em 0 .225em;line-height:1.3334;font-size:.875em;margin-left:1.2em;margin-bottom:.2em}
 334 #footnotes .footnote a:first-of-type{font-weight:bold;text-decoration:none;margin-left:-1.05em}
 335 #footnotes .footnote:last-of-type{margin-bottom:0}
 336 #content #footnotes{margin-top:-.625em;margin-bottom:0;padding:.75em 0}
 337 div.unbreakable{page-break-inside:avoid}
 338 .big{font-size:larger}
 339 .small{font-size:smaller}
 340 .underline{text-decoration:underline}
 341 .overline{text-decoration:overline}
 342 .line-through{text-decoration:line-through}
 343 .aqua{color:#00bfbf}
 344 .aqua-background{background:#00fafa}
 345 .black{color:#000}
 346 .black-background{background:#000}
 347 .blue{color:#0000bf}
 348 .blue-background{background:#0000fa}
 349 .fuchsia{color:#bf00bf}
 350 .fuchsia-background{background:#fa00fa}
 351 .gray{color:#606060}
 352 .gray-background{background:#7d7d7d}
 353 .green{color:#006000}
 354 .green-background{background:#007d00}
 355 .lime{color:#00bf00}
 356 .lime-background{background:#00fa00}
 357 .maroon{color:#600000}
 358 .maroon-background{background:#7d0000}
 359 .navy{color:#000060}
 360 .navy-background{background:#00007d}
 361 .olive{color:#606000}
 362 .olive-background{background:#7d7d00}
 363 .purple{color:#600060}
 364 .purple-background{background:#7d007d}
 365 .red{color:#bf0000}
 366 .red-background{background:#fa0000}
 367 .silver{color:#909090}
 368 .silver-background{background:#bcbcbc}
 369 .teal{color:#006060}
 370 .teal-background{background:#007d7d}
 371 .white{color:#bfbfbf}
 372 .white-background{background:#fafafa}
 373 .yellow{color:#bfbf00}
 374 .yellow-background{background:#fafa00}
 375 span.icon>.fa{cursor:default}
 376 a span.icon>.fa{cursor:inherit}
 377 .admonitionblock td.icon [class^="fa icon-"]{font-size:2.5em;text-shadow:1px 1px 2px rgba(0,0,0,.5);cursor:default}
 378 .admonitionblock td.icon .icon-note::before{content:"\f05a";color:#19407c}
 379 .admonitionblock td.icon .icon-tip::before{content:"\f0eb";text-shadow:1px 1px 2px rgba(155,155,0,.8);color:#111}
 380 .admonitionblock td.icon .icon-warning::before{content:"\f071";color:#bf6900}
 381 .admonitionblock td.icon .icon-caution::before{content:"\f06d";color:#bf3400}
 382 .admonitionblock td.icon .icon-important::before{content:"\f06a";color:#bf0000}
 383 .conum[data-value]{display:inline-block;color:#fff!important;background:rgba(0,0,0,.8);border-radius:50%;text-align:center;font-size:.75em;width:1.67em;height:1.67em;line-height:1.67em;font-family:"Open Sans","DejaVu Sans",sans-serif;font-style:normal;font-weight:bold}
 384 .conum[data-value] *{color:#fff!important}
 385 .conum[data-value]+b{display:none}
 386 .conum[data-value]::after{content:attr(data-value)}
 387 pre .conum[data-value]{position:relative;top:-.125em}
 388 b.conum *{color:inherit!important}
 389 .conum:not([data-value]):empty{display:none}
 390 dt,th.tableblock,td.content,div.footnote{text-rendering:optimizeLegibility}
 391 h1,h2,p,td.content,span.alt,summary{letter-spacing:-.01em}
 392 p strong,td.content strong,div.footnote strong{letter-spacing:-.005em}
 393 p,blockquote,dt,td.content,td.hdlist1,span.alt,summary{font-size:1.0625rem}
 394 p{margin-bottom:1.25rem}
 395 .sidebarblock p,.sidebarblock dt,.sidebarblock td.content,p.tableblock{font-size:1em}
 396 .exampleblock>.content{background:#fffef7;border-color:#e0e0dc;box-shadow:0 1px 4px #e0e0dc}
 397 .print-only{display:none!important}
 398 @page{margin:1.25cm .75cm}
 399 @media print{*{box-shadow:none!important;text-shadow:none!important}
 400 html{font-size:80%}
 401 a{color:inherit!important;text-decoration:underline!important}
 402 a.bare,a[href^="#"],a[href^="mailto:"]{text-decoration:none!important}
 403 a[href^="http:"]:not(.bare)::after,a[href^="https:"]:not(.bare)::after{content:"(" attr(href) ")";display:inline-block;font-size:.875em;padding-left:.25em}
 404 abbr[title]{border-bottom:1px dotted}
 405 abbr[title]::after{content:" (" attr(title) ")"}
 406 pre,blockquote,tr,img,object,svg{page-break-inside:avoid}
 407 thead{display:table-header-group}
 408 svg{max-width:100%}
 409 p,blockquote,dt,td.content{font-size:1em;orphans:3;widows:3}
 410 h2,h3,#toctitle,.sidebarblock>.content>.title{page-break-after:avoid}
 411 #header,#content,#footnotes,#footer{max-width:none}
 412 #toc,.sidebarblock,.exampleblock>.content{background:none!important}
 413 #toc{border-bottom:1px solid #dddddf!important;padding-bottom:0!important}
 414 body.book #header{text-align:center}
 415 body.book #header>h1:first-child{border:0!important;margin:2.5em 0 1em}
 416 body.book #header .details{border:0!important;display:block;padding:0!important}
 417 body.book #header .details span:first-child{margin-left:0!important}
 418 body.book #header .details br{display:block}
 419 body.book #header .details br+span::before{content:none!important}
 420 body.book #toc{border:0!important;text-align:left!important;padding:0!important;margin:0!important}
 421 body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-break-before:always}
 422 .listingblock code[data-lang]::before{display:block}
 423 #footer{padding:0 .9375em}
 424 .hide-on-print{display:none!important}
 425 .print-only{display:block!important}
 426 .hide-for-print{display:none!important}
 427 .show-for-print{display:inherit!important}}
 428 @media amzn-kf8,print{#header>h1:first-child{margin-top:1.25rem}
 429 .sect1{padding:0!important}
 430 .sect1+.sect1{border:0}
 431 #footer{background:none}
 432 #footer-text{color:rgba(0,0,0,.6);font-size:.9em}}
 433 @media amzn-kf8{#header,#content,#footnotes,#footer{padding:0}}
 434 </style>
 435 </head>
 436 <body class="article">
 437 <div id="header">
 438 <h1>Shallow commits</h1>
 439 <div class="details">
 440 <span id="revdate">2024-11-20</span>
 441 </div>
 442 </div>
 443 <div id="content">
 444 <div class="sidebarblock">
 445 <div class="content">
 446 <div class="title">Definition</div>
 447 <div class="paragraph">
 448 <p>Shallow commits do have parents, but not in the shallow
 449 repo, and therefore grafts are introduced pretending that
 450 these commits have no parents.</p>
 451 </div>
 452 </div>
 453 </div>
 454 <div class="paragraph">
 455 <p>$GIT_DIR/shallow lists commit object names and tells Git to
 456 pretend as if they are root commits (e.g. "git log" traversal
 457 stops after showing them; "git fsck" does not complain saying
 458 the commits listed on their "parent" lines do not exist).</p>
 459 </div>
 460 <div class="paragraph">
 461 <p>Each line contains exactly one object name. When read, a commit_graft
 462 will be constructed, which has nr_parent &lt; 0 to make it easier
 463 to discern from user provided grafts.</p>
 464 </div>
 465 <div class="paragraph">
 466 <p>Note that the shallow feature could not be changed easily to
 467 use replace refs: a commit containing a <code>mergetag</code> is not allowed
 468 to be replaced, not even by a root commit. Such a commit can be
 469 made shallow, though. Also, having a <code>shallow</code> file explicitly
 470 listing all the commits made shallow makes it a <strong>lot</strong> easier to
 471 do shallow-specific things such as to deepen the history.</p>
 472 </div>
 473 <div class="paragraph">
 474 <p>Since fsck-objects relies on the library to read the objects,
 475 it honours shallow commits automatically.</p>
 476 </div>
 477 <div class="paragraph">
 478 <p>There are some unfinished ends of the whole shallow business:</p>
 479 </div>
 480 <div class="ulist">
 481 <ul>
 482 <li>
 483 <p>maybe we have to force non-thin packs when fetching into a
 484 shallow repo (ATM they are forced non-thin).</p>
 485 </li>
 486 <li>
 487 <p>A special handling of a shallow upstream is needed. At some
 488 stage, upload-pack has to check if it sends a shallow commit,
 489 and it should send that information early (or fail, if the
 490 client does not support shallow repositories). There is no
 491 support at all for this in this patch series.</p>
 492 </li>
 493 <li>
 494 <p>Instead of locking $GIT_DIR/shallow at the start, just
 495 the timestamp of it is noted, and when it comes to writing it,
 496 a check is performed if the mtime is still the same, dying if
 497 it is not.</p>
 498 </li>
 499 <li>
 500 <p>It is unclear how "push into/from a shallow repo" should behave.</p>
 501 </li>
 502 <li>
 503 <p>If you deepen a history, you&#8217;d want to get the tags of the
 504 newly stored (but older!) commits. This does not work right now.</p>
 505 </li>
 506 </ul>
 507 </div>
 508 <div class="paragraph">
 509 <p>To make a shallow clone, you can call "git-clone --depth 20 repo".
 510 The result contains only commit chains with a length of at most 20.
 511 It also writes an appropriate $GIT_DIR/shallow.</p>
 512 </div>
 513 <div class="paragraph">
 514 <p>You can deepen a shallow repository with "git-fetch --depth 20
 515 repo branch", which will fetch branch from repo, but stop at depth
 516 20, updating $GIT_DIR/shallow.</p>
 517 </div>
 518 <div class="paragraph">
 519 <p>The special depth 2147483647 (or 0x7fffffff, the largest positive
 520 number a signed 32-bit integer can contain) means infinite depth.</p>
 521 </div>
 522 </div>
 523 <div id="footer">
 524 <div id="footer-text">
 525 Last updated 2020-08-20 14:10:31 +0900
 526 </div>
 527 </div>
 528 </body>
 529 </html>