func parentsRemoved(parents []dag.Node, record *db.BuildRecord) bool {
parentset := make(map[string]bool)
for _, parent := range parents {
parentset[parent.Name()] = true
}
for _, name := range record.Parents() {
if !parentset[name] {
return true
}
}
return false
}
// Inspect node and its parents to see if we need to build it. Return
// build=true if we should build it, tainted=true if we should skip
// building this node due to upstream failure. Return non-nil err if
// there were unexpected node errors (error checking existence or
// change status).
func (self *BuildState) considerNode(node dag.Node) (
build bool, tainted bool, err error) {
var exists, changed bool
exists, err = node.Exists() // obvious rebuild (unless tainted)
if err != nil {
return
}
missing := !exists
var record *db.BuildRecord
if !missing {
// skip DB lookup for missing nodes: the only thing that will
// stop us from rebuilding them is a failed parent, and that
// check comes later
record, err = self.db.LookupNode(node.Name())
if err != nil {
return
}
if record != nil {
log.Debug(log.BUILD, "old parents of %s:", node)
log.DebugDump(log.BUILD, record)
}
}
build = missing
parents := self.graph.ParentNodes(node)
// Check if any of node's former parents have been removed.
if !build && record != nil {
build = parentsRemoved(parents, record)
}
for _, parent := range parents {
pstate := parent.State()
if pstate == dag.FAILED || pstate == dag.TAINTED {
build = false
tainted = true
return // no further inspection required
}
var oldsig []byte
if record != nil {
oldsig = record.SourceSignature(parent.Name())
}
if oldsig == nil {
// New parent for this node: rebuild unless another
// parent is failed/tainted.
build = true
}
if build {
continue
}
changed, err = self.parentChanged(parent, pstate, oldsig)
if err != nil {
return
}
if changed {
// Do NOT return here: we need to continue inspecting
// parents to make sure they don't taint this node with
// upstream failure.
build = true
}
}
return
}