2014-08-27 16:41:09 +00:00
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="sec-debug-build">
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<title>Debugging Build Failures</title>
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2014-12-14 00:39:32 +00:00
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<para>At the beginning of each phase of the build (such as unpacking,
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building or installing), the set of all shell variables is written to
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the file <filename>env-vars</filename> at the top-level build
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directory. This is useful for debugging: it allows you to recreate
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the environment in which a build was performed. For instance, if a
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build fails, then assuming you used the <option>-K</option> flag, you
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can go to the output directory and <quote>switch</quote> to the
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environment of the builder:
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2014-08-27 16:41:09 +00:00
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<screen>
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$ nix-build -K ./foo.nix
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... fails, keeping build directory `/tmp/nix-1234-0'
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$ cd /tmp/nix-1234-0
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$ source env-vars
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<lineannotation>(edit some files...)</lineannotation>
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$ make
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<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen>
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</para>
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2014-12-14 00:39:32 +00:00
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</section>
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