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-rw-r--r--nix/libstore/build.cc61
1 files changed, 51 insertions, 10 deletions
diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 64678a5594..e19c32b1c9 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -785,10 +785,16 @@ private:
temporary paths. */
PathSet redirectedBadOutputs;
- /* Set of inodes seen during calls to canonicalisePathMetaData()
- for this build's outputs. This needs to be shared between
- outputs to allow hard links between outputs. */
- InodesSeen inodesSeen;
+ /* The current round, if we're building multiple times. */
+ unsigned int curRound = 1;
+
+ unsigned int nrRounds;
+
+ /* Path registration info from the previous round, if we're
+ building multiple times. Since this contains the hash, it
+ allows us to compare whether two rounds produced the same
+ result. */
+ ValidPathInfos prevInfos;
public:
DerivationGoal(const Path & drvPath, const StringSet & wantedOutputs, Worker & worker, BuildMode buildMode = bmNormal);
@@ -1194,8 +1200,12 @@ void DerivationGoal::inputsRealised()
/* Is this a fixed-output derivation? */
fixedOutput = true;
- foreach (DerivationOutputs::iterator, i, drv.outputs)
- if (i->second.hash == "") fixedOutput = false;
+ for (auto & i : drv.outputs)
+ if (i.second.hash == "") fixedOutput = false;
+
+ /* Don't repeat fixed-output derivations since they're already
+ verified by their output hash.*/
+ nrRounds = fixedOutput ? 1 : settings.get("build-repeat", 0) + 1;
/* Okay, try to build. Note that here we don't wait for a build
slot to become available, since we don't need one if there is a
@@ -1371,6 +1381,9 @@ void replaceValidPath(const Path & storePath, const Path tmpPath)
}
+MakeError(NotDeterministic, BuildError)
+
+
void DerivationGoal::buildDone()
{
trace("build done");
@@ -1470,6 +1483,15 @@ void DerivationGoal::buildDone()
deleteTmpDir(true);
+ /* Repeat the build if necessary. */
+ if (curRound++ < nrRounds) {
+ outputLocks.unlock();
+ buildUser.release();
+ state = &DerivationGoal::tryToBuild;
+ worker.wakeUp(shared_from_this());
+ return;
+ }
+
/* It is now safe to delete the lock files, since all future
lockers will see that the output paths are valid; they will
not create new lock files with the same names as the old
@@ -1623,10 +1645,13 @@ int childEntry(void * arg)
void DerivationGoal::startBuilder()
{
- startNest(nest, lvlInfo, format(
- buildMode == bmRepair ? "repairing path(s) %1%" :
- buildMode == bmCheck ? "checking path(s) %1%" :
- "building path(s) %1%") % showPaths(missingPaths));
+ auto f = format(
+ buildMode == bmRepair ? "repairing path(s) %1%" :
+ buildMode == bmCheck ? "checking path(s) %1%" :
+ nrRounds > 1 ? "building path(s) %1% (round %2%/%3%)" :
+ "building path(s) %1%");
+ f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
+ startNest(nest, lvlInfo, f % showPaths(missingPaths) % curRound % nrRounds);
/* Right platform? */
if (!canBuildLocally(drv.platform)) {
@@ -1638,6 +1663,7 @@ void DerivationGoal::startBuilder()
}
/* Construct the environment passed to the builder. */
+ env.clear();
/* Most shells initialise PATH to some default (/bin:/usr/bin:...) when
PATH is not set. We don't want this, so we fill it in with some dummy
@@ -2267,6 +2293,11 @@ void DerivationGoal::registerOutputs()
ValidPathInfos infos;
+ /* Set of inodes seen during calls to canonicalisePathMetaData()
+ for this build's outputs. This needs to be shared between
+ outputs to allow hard links between outputs. */
+ InodesSeen inodesSeen;
+
/* Check whether the output paths were created, and grep each
output path to determine what other paths it references. Also make all
output paths read-only. */
@@ -2438,6 +2469,16 @@ void DerivationGoal::registerOutputs()
if (buildMode == bmCheck) return;
+ if (curRound > 1 && prevInfos != infos)
+ throw NotDeterministic(
+ format("result of ‘%1%’ differs from previous round; rejecting as non-deterministic")
+ % drvPath);
+
+ if (curRound < nrRounds) {
+ prevInfos = infos;
+ return;
+ }
+
/* Register each output path as valid, and register the sets of
paths referenced by each of them. If there are cycles in the
outputs, this will fail. */