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Use $<attr>Path instead of $<attr> for passAsFile

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This commit is contained in:
Eelco Dolstra 2015-02-17 16:42:54 +01:00
parent a70d275f3d
commit bd91064150
3 changed files with 13 additions and 7 deletions
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16
doc/manual/expressions/advanced-attributes.xml
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@ -254,11 +254,17 @@ big = "a very long string";
</programlisting> </programlisting>
then when the builder runs, the environment variable then when the builder runs, the environment variable
<envar>big</envar> will contain the absolute path to a temporary <envar>bigPath</envar> will contain the absolute path to a
file containing <literal>a very long string</literal>. This is temporary file containing <literal>a very long
useful when you need to pass large strings to a builder, since string</literal>. That is, for any attribute
most operating systems impose a limit on the size of the <replaceable>x</replaceable> listed in
environment (typically, a few hundred kilobyte).</para></listitem> <varname>passAsFile</varname>, Nix will pass an environment
variable <envar><replaceable>x</replaceable>Path</envar> holding
the path of the file containing the value of attribute
<replaceable>x</replaceable>. This is useful when you need to pass
large strings to a builder, since most operating systems impose a
limit on the size of the environment (typically, a few hundred
kilobyte).</para></listitem>
</varlistentry> </varlistentry>

2
src/libstore/build.cc
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@ -1662,7 +1662,7 @@ void DerivationGoal::startBuilder()
} else { } else {
Path p = tmpDir + "/.attr-" + int2String(fileNr++); Path p = tmpDir + "/.attr-" + int2String(fileNr++);
writeFile(p, i.second); writeFile(p, i.second);
env[i.first] = p; env[i.first + "Path"] = p;
} }
} }

2
tests/pass-as-file.sh
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@ -10,7 +10,7 @@ mkDerivation {
passAsFile = [ \"foo\" ]; passAsFile = [ \"foo\" ];
foo = [ \"xyzzy\" ]; foo = [ \"xyzzy\" ];
builder = builtins.toFile \"builder.sh\" '' builder = builtins.toFile \"builder.sh\" ''
[ \"\$(cat \$foo)\" = xyzzy ] [ \"\$(cat \$fooPath)\" = xyzzy ]
touch \$out touch \$out
''; '';
} }