hgweb: display blamed revision once per block in annotate view

hgweb: display blamed revision once per block in annotate view

I.e. when a revision blames a block of source lines, only display the
revision link on the first line of the block (this is identified by the
"blockhead" key in annotate context).

This addresses item "Visual grouping of changesets" of the blame improvements
plan (https://www.mercurial-scm.org/wiki/BlamePlan) which states: "Typically
there are block of lines all attributed to the same revision. Instead of
rendering the revision/changeset for every line, we could only render it once
per block."

--- a/mercurial/hgweb/webcommands.py	Thu Jun 02 16:26:50 2016 +0200
+++ b/mercurial/hgweb/webcommands.py	Tue Jun 07 12:10:01 2016 +0200
@@ -872,14 +872,19 @@
         else:
             lines = enumerate(fctx.annotate(follow=True, linenumber=True,
                                             diffopts=diffopts))
+        previousrev = None
         for lineno, ((f, targetline), l) in lines:
+            rev = f.rev()
+            blockhead = rev != previousrev or None
+            previousrev = rev
             yield {"parity": next(parity),
                    "node": f.hex(),
-                   "rev": f.rev(),
+                   "rev": rev,
                    "author": f.user(),
                    "desc": f.description(),
                    "extra": f.extra(),
                    "file": f.path(),
+                   "blockhead": blockhead,
                    "targetline": targetline,
                    "line": l,
                    "lineno": lineno + 1,

--- a/mercurial/templates/gitweb/map	Thu Jun 02 16:26:50 2016 +0200
+++ b/mercurial/templates/gitweb/map	Tue Jun 07 12:10:01 2016 +0200
@@ -97,8 +97,10 @@
 annotateline = '
   <tr id="{lineid}" style="font-family:monospace" class="parity{parity}{ifeq(node, originalnode, ' thisrev')}">
     <td class="linenr" style="text-align: right;">
-      <a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
-         title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>
+      {if(blockhead,
+          '<a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
+              title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>',
+          '')}
     </td>
     <td><pre><a class="linenr" href="#{lineid}">{linenumber}</a></pre></td>
     <td><pre>{line|escape}</pre></td>

--- a/mercurial/templates/monoblue/map	Thu Jun 02 16:26:50 2016 +0200
+++ b/mercurial/templates/monoblue/map	Tue Jun 07 12:10:01 2016 +0200
@@ -93,8 +93,10 @@
 annotateline = '
   <tr id="{lineid}" class="parity{parity}{ifeq(node, originalnode, ' thisrev')}">
     <td class="linenr">
-      <a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
-         title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>
+      {if(blockhead,
+          '<a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
+              title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>',
+          '')}
     </td>
     <td class="lineno">
       <a href="#{lineid}">{linenumber}</a>

--- a/mercurial/templates/paper/map	Thu Jun 02 16:26:50 2016 +0200
+++ b/mercurial/templates/paper/map	Tue Jun 07 12:10:01 2016 +0200
@@ -78,8 +78,10 @@
 annotateline = '
   <tr id="{lineid}"{ifeq(node, originalnode, ' class="thisrev"')}>
     <td class="annotate">
-      <a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
-         title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>
+      {if(blockhead,
+          '<a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
+              title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>',
+          '')}
     </td>
     <td class="source"><a href="#{lineid}">{linenumber}</a> {line|escape}</td>
   </tr>'

--- a/mercurial/templates/spartan/map	Thu Jun 02 16:26:50 2016 +0200
+++ b/mercurial/templates/spartan/map	Tue Jun 07 12:10:01 2016 +0200
@@ -56,8 +56,10 @@
 annotateline = '
   <tr class="parity{parity}{ifeq(node, originalnode, ' thisrev')}">
     <td class="annotate">
-      <a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
-         title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>
+      {if(blockhead,
+          '<a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}#l{targetline}"
+              title="{node|short}: {desc|escape|firstline}">{author|user}@{rev}</a>',
+          '')}
     </td>
     <td>
       <a class="lineno" href="#{lineid}" id="{lineid}">{linenumber}</a>

--- a/tests/test-highlight.t	Thu Jun 02 16:26:50 2016 +0200
+++ b/tests/test-highlight.t	Tue Jun 07 12:10:01 2016 +0200
@@ -297,225 +297,193 @@
   </tr>
   <tr id="l2" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l2"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l2">     2</a> </td>
   </tr>
   <tr id="l3" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l3"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l3">     3</a> <span class="sd">&quot;&quot;&quot;Fun with generators. Corresponding Haskell implementation:</span></td>
   </tr>
   <tr id="l4" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l4"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l4">     4</a> </td>
   </tr>
   <tr id="l5" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l5"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l5">     5</a> <span class="sd">primes = 2 : sieve [3, 5..]</span></td>
   </tr>
   <tr id="l6" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l6"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l6">     6</a> <span class="sd">    where sieve (p:ns) = p : sieve [n | n &lt;- ns, mod n p /= 0]</span></td>
   </tr>
   <tr id="l7" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l7"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l7">     7</a> <span class="sd">&quot;&quot;&quot;</span></td>
   </tr>
   <tr id="l8" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l8"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l8">     8</a> </td>
   </tr>
   <tr id="l9" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l9"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l9">     9</a> <span class="kn">from</span> <span class="nn">itertools</span> <span class="kn">import</span> <span class="n">dropwhile</span><span class="p">,</span> <span class="n">ifilter</span><span class="p">,</span> <span class="n">islice</span><span class="p">,</span> <span class="n">count</span><span class="p">,</span> <span class="n">chain</span></td>
   </tr>
   <tr id="l10" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l10"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l10">    10</a> </td>
   </tr>
   <tr id="l11" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l11"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l11">    11</a> <span class="kn">def</span> <span class="nf">primes</span><span class="p">():</span></td>
   </tr>
   <tr id="l12" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l12"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l12">    12</a>     <span class="sd">&quot;&quot;&quot;Generate all primes.&quot;&quot;&quot;</span></td>
   </tr>
   <tr id="l13" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l13"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l13">    13</a>     <span class="kn">def</span> <span class="nf">sieve</span><span class="p">(</span><span class="n">ns</span><span class="p">):</span></td>
   </tr>
   <tr id="l14" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l14"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l14">    14</a>         <span class="n">p</span> <span class="o">=</span> <span class="n">ns</span><span class="o">.</span><span class="n">next</span><span class="p">()</span></td>
   </tr>
   <tr id="l15" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l15"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l15">    15</a>         <span class="c"># It is important to yield *here* in order to stop the</span></td>
   </tr>
   <tr id="l16" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l16"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l16">    16</a>         <span class="c"># infinite recursion.</span></td>
   </tr>
   <tr id="l17" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l17"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l17">    17</a>         <span class="kn">yield</span> <span class="n">p</span></td>
   </tr>
   <tr id="l18" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l18"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l18">    18</a>         <span class="n">ns</span> <span class="o">=</span> <span class="n">ifilter</span><span class="p">(</span><span class="kn">lambda</span> <span class="n">n</span><span class="p">:</span> <span class="n">n</span> <span class="o">%</span> <span class="n">p</span> <span class="o">!=</span> <span class="mi">0</span><span class="p">,</span> <span class="n">ns</span><span class="p">)</span></td>
   </tr>
   <tr id="l19" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l19"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l19">    19</a>         <span class="kn">for</span> <span class="n">n</span> <span class="ow">in</span> <span class="n">sieve</span><span class="p">(</span><span class="n">ns</span><span class="p">):</span></td>
   </tr>
   <tr id="l20" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l20"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l20">    20</a>             <span class="kn">yield</span> <span class="n">n</span></td>
   </tr>
   <tr id="l21" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l21"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l21">    21</a> </td>
   </tr>
   <tr id="l22" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l22"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l22">    22</a>     <span class="n">odds</span> <span class="o">=</span> <span class="n">ifilter</span><span class="p">(</span><span class="kn">lambda</span> <span class="n">i</span><span class="p">:</span> <span class="n">i</span> <span class="o">%</span> <span class="mi">2</span> <span class="o">==</span> <span class="mi">1</span><span class="p">,</span> <span class="n">count</span><span class="p">())</span></td>
   </tr>
   <tr id="l23" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l23"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l23">    23</a>     <span class="kn">return</span> <span class="n">chain</span><span class="p">([</span><span class="mi">2</span><span class="p">],</span> <span class="n">sieve</span><span class="p">(</span><span class="n">dropwhile</span><span class="p">(</span><span class="kn">lambda</span> <span class="n">n</span><span class="p">:</span> <span class="n">n</span> <span class="o">&lt;</span> <span class="mi">3</span><span class="p">,</span> <span class="n">odds</span><span class="p">)))</span></td>
   </tr>
   <tr id="l24" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l24"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l24">    24</a> </td>
   </tr>
   <tr id="l25" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l25"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l25">    25</a> <span class="kn">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">&quot;__main__&quot;</span><span class="p">:</span></td>
   </tr>
   <tr id="l26" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l26"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l26">    26</a>     <span class="kn">import</span> <span class="nn">sys</span></td>
   </tr>
   <tr id="l27" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l27"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l27">    27</a>     <span class="kn">try</span><span class="p">:</span></td>
   </tr>
   <tr id="l28" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l28"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l28">    28</a>         <span class="n">n</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">sys</span><span class="o">.</span><span class="n">argv</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span></td>
   </tr>
   <tr id="l29" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l29"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l29">    29</a>     <span class="kn">except</span> <span class="p">(</span><span class="ne">ValueError</span><span class="p">,</span> <span class="ne">IndexError</span><span class="p">):</span></td>
   </tr>
   <tr id="l30" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l30"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l30">    30</a>         <span class="n">n</span> <span class="o">=</span> <span class="mi">10</span></td>
   </tr>
   <tr id="l31" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l31"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l31">    31</a>     <span class="n">p</span> <span class="o">=</span> <span class="n">primes</span><span class="p">()</span></td>
   </tr>
   <tr id="l32" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l32"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l32">    32</a>     <span class="kn">print</span> <span class="s">&quot;The first </span><span class="si">%d</span><span class="s"> primes: </span><span class="si">%s</span><span class="s">&quot;</span> <span class="o">%</span> <span class="p">(</span><span class="n">n</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">islice</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="n">n</span><span class="p">)))</span></td>
   </tr>
   <tr id="l33" class="thisrev">
   <td class="annotate">
-  <a href="/annotate/06824edf55d0/primes.py#l33"
-  title="06824edf55d0: a">test@0</a>
+  
   </td>
   <td class="source"><a href="#l33">    33</a> </td>
   </tr>