Pastable version of Rails migration conflict repair

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            <pre class="sunburst">namespace <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>migrations</span> <span style="color:#E28964;">do</span>
  
  desc <span style="color:#65B042;"><span style="color:#65B042;">'</span>reverts, renames and re-executes uncommitted migrations that conflict with already committed migrations<span style="color:#65B042;">'</span></span>
  task <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>repair</span> =&gt; <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>environment</span> <span style="color:#E28964;">do</span>
    uncommitted <span style="color:#E28964;">=</span> <span style="color:#65B042;"><span style="color:#65B042;">`</span>svn status<span style="color:#65B042;">`</span></span>.<span style="color:#89BDFF;">select</span> {|<span style="color:#3E87E3;">line</span>| line <span style="color:#E28964;">=~</span> <span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span><span style="color:#E9C062;">db<span style="color:#CF7D34;">\/</span>migrate<span style="color:#CF7D34;">\/</span></span><span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span>}.<span style="color:#89BDFF;">collect</span> {|<span style="color:#3E87E3;">line</span>| line.<span style="color:#89BDFF;">match</span>(<span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span><span style="color:#E9C062;"> db<span style="color:#CF7D34;">\/</span>migrate<span style="color:#CF7D34;">\/</span><span style="color:#E9C062;"><span style="color:#E9C062;">(</span>.*rb<span style="color:#E9C062;">)</span></span></span><span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span>)[<span style="color:#3387CC;">1</span>]}
    committed   <span style="color:#E28964;">=</span> <span style="color:#9B859D;">Dir</span>.<span style="color:#89BDFF;">glob</span>(<span style="color:#65B042;"><span style="color:#65B042;">'</span>db/migrate/*<span style="color:#65B042;">'</span></span>).<span style="color:#89BDFF;">collect</span> {|<span style="color:#3E87E3;">line</span>| line.<span style="color:#89BDFF;">match</span>(<span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span><span style="color:#E9C062;">db<span style="color:#CF7D34;">\/</span>migrate<span style="color:#CF7D34;">\/</span><span style="color:#E9C062;"><span style="color:#E9C062;">(</span>.*rb<span style="color:#E9C062;">)</span></span></span><span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span>)[<span style="color:#3387CC;">1</span>]} <span style="color:#E28964;">-</span> uncommitted
    
    highest_committed   <span style="color:#E28964;">=</span> committed.<span style="color:#89BDFF;">collect</span>(<span style="color:#E28964;">&amp;</span><span style="color:#3387CC;"><span style="color:#3387CC;">:</span>to_i</span>).<span style="color:#89BDFF;">max</span>
    lowest_uncommitted  <span style="color:#E28964;">=</span> uncommitted.<span style="color:#89BDFF;">collect</span>(<span style="color:#E28964;">&amp;</span><span style="color:#3387CC;"><span style="color:#3387CC;">:</span>to_i</span>).<span style="color:#89BDFF;">min</span>
    
    schema_version <span style="color:#E28964;">=</span> <span style="color:#9B859D;">ActiveRecord</span>::<span style="color:#89BDFF;">Base</span>.<span style="color:#89BDFF;">connection</span>.<span style="color:#89BDFF;">select_one</span>(<span style="color:#65B042;"><span style="color:#65B042;">&quot;</span>select version from schema_info<span style="color:#65B042;">&quot;</span></span>)[<span style="color:#65B042;"><span style="color:#65B042;">&quot;</span>version<span style="color:#65B042;">&quot;</span></span>].<span style="color:#89BDFF;">to_i</span>
    
<span style="color:#AEAEAE;font-style:italic;">    <span style="color:#AEAEAE;font-style:italic;">#</span> revert uncommitted migrations</span>
    uncommitted.<span style="color:#89BDFF;">sort_by</span>(<span style="color:#E28964;">&amp;</span><span style="color:#3387CC;"><span style="color:#3387CC;">:</span>to_i</span>).<span style="color:#89BDFF;">reverse</span>.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">migration</span>|
      version <span style="color:#E28964;">=</span> migration.<span style="color:#89BDFF;">to_i</span>
      <span style="color:#E28964;">if</span> version <span style="color:#E28964;">&lt;=</span> schema_version
        name <span style="color:#E28964;">=</span> migration.<span style="color:#89BDFF;">match</span>(<span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span><span style="color:#E9C062;"><span style="color:#E9C062;"><span style="color:#E9C062;">(</span><span style="color:#CF7D34;">\d</span>*_.*<span style="color:#E9C062;">)</span></span>.rb</span><span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span>)[<span style="color:#3387CC;">1</span>]
        class_name <span style="color:#E28964;">=</span> (<span style="color:#E28964;">require</span> <span style="color:#65B042;"><span style="color:#65B042;">'</span>db/migrate/<span style="color:#65B042;">'</span></span> <span style="color:#E28964;">+</span> name)[<span style="color:#3387CC;">0</span>]
        puts class_name.<span style="color:#89BDFF;">constantize</span>.<span style="color:#89BDFF;">down</span> 
      <span style="color:#E28964;">end</span>
    <span style="color:#E28964;">end</span>
    
<span style="color:#AEAEAE;font-style:italic;">    <span style="color:#AEAEAE;font-style:italic;">#</span>set it back to the version prior to all the uncommitted migrations - this doesn't get done automatically by calling down</span>
    <span style="color:#9B859D;">ActiveRecord</span>::<span style="color:#89BDFF;">Base</span>.<span style="color:#89BDFF;">connection</span>.<span style="color:#89BDFF;">execute</span>(<span style="color:#65B042;"><span style="color:#65B042;">&quot;</span>update schema_info set version=<span style="color:#DAEFA3;"><span style="color:#DAEFA3;">#{</span>schema_version<span style="color:#E28964;">-</span><span style="color:#DDF2A4;">1</span><span style="color:#DAEFA3;">}</span></span><span style="color:#65B042;">&quot;</span></span>)
    
    version_offset <span style="color:#E28964;">=</span> (highest_committed <span style="color:#E28964;">-</span> lowest_uncommitted) <span style="color:#E28964;">+</span> <span style="color:#3387CC;">1</span>
    
    uncommitted.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">old_name</span>|
      version  <span style="color:#E28964;">=</span> old_name.<span style="color:#89BDFF;">to_i</span> <span style="color:#E28964;">+</span> version_offset
      new_name <span style="color:#E28964;">=</span> version.<span style="color:#89BDFF;">to_s</span>.<span style="color:#89BDFF;">rjust</span>(<span style="color:#3387CC;">3</span>,<span style="color:#65B042;"><span style="color:#65B042;">'</span>0<span style="color:#65B042;">'</span></span>) <span style="color:#E28964;">+</span> old_name.<span style="color:#89BDFF;">gsub</span>(<span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span><span style="color:#E9C062;"><span style="color:#CF7D34;">\d</span></span><span style="color:#E9C062;"><span style="color:#E9C062;">/</span></span>, <span style="color:#65B042;"><span style="color:#65B042;">'</span><span style="color:#65B042;">'</span></span>)
      <span style="color:#65B042;"><span style="color:#65B042;">`</span>mv db/migrate/<span style="color:#65B042;"><span style="color:#65B042;">#{</span>old_name<span style="color:#65B042;">}</span></span> db/migrate/<span style="color:#65B042;"><span style="color:#65B042;">#{</span>new_name<span style="color:#65B042;">}</span></span><span style="color:#65B042;">`</span></span>
    <span style="color:#E28964;">end</span>
    
    puts <span style="color:#65B042;"><span style="color:#65B042;">&quot;</span>Uncommited migrations have been reversed and renamed. You can now migrate.<span style="color:#65B042;">&quot;</span></span>
  <span style="color:#E28964;">end</span>
<span style="color:#E28964;">end</span>
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