/// <summary>
/// Some validations and operations require knowledge of whether a mount is nested under another mount.
/// </summary>
/// <returns>true if the operations were performed successfully</returns>
private bool AddAndPerformNestingOperations()
{
bool success = true;
// flip alternative roots -> mount map for easier lookup
var alternativeRoots = m_alternativeRoots.ToMultiValueDictionary(kvp => kvp.Value, kvp => kvp.Key);
// Compute the depth of each mount root so parent mounts can be visited first
List <KeyValuePair <int, IMount> > mountsByRootDepth = new List <KeyValuePair <int, IMount> >();
foreach (IMount mount in m_mountMapBuilder.Values)
{
int depth = 0;
AbsolutePath path = mount.Path;
while (path.IsValid)
{
path = path.GetParent(m_context.PathTable);
depth++;
}
mountsByRootDepth.Add(new KeyValuePair <int, IMount>(depth, mount));
}
mountsByRootDepth.Sort((depthAndMount1, depthAndMount2) => depthAndMount1.Key.CompareTo(depthAndMount2.Key));
foreach (var mountEntry in mountsByRootDepth)
{
var childMount = mountEntry.Value;
var parentMountInfo = MountPathExpander.GetSemanticPathInfo(childMount.Path);
if (parentMountInfo.IsValid)
{
IMount parentMount;
if (!m_mountMapBuilder.TryGetValue(parentMountInfo.Root, out parentMount) && m_parent != null)
{
parentMount = m_parent.m_mountMapBuilder[parentMountInfo.Root];
}
if (parentMount.IsScrubbable && !childMount.IsScrubbable)
{
LogRelatedMountError(
Logger.Log.ScrubbableMountsMayOnlyContainScrubbableMounts,
childMount: childMount,
parentMount: parentMount);
success = false;
}
}
// TODO: Does not adding on success == false change behavior
if (success)
{
MountPathExpander.Add(m_context.PathTable, childMount);
if (alternativeRoots.TryGetValue(childMount, out var additionalRoots))
{
foreach (var root in additionalRoots)
{
MountPathExpander.AddWithExistingName(
m_context.PathTable,
new SemanticPathInfo(childMount.Name, root, childMount.TrackSourceFileChanges, childMount.IsReadable, childMount.IsWritable, childMount.IsSystem, childMount.IsScrubbable, childMount.AllowCreateDirectory));
}
}
}
}
return(success);
}
/// <summary>
/// Some validations and operations require knowledge of whether a mount is nested under another mount.
/// </summary>
/// <returns>true if the operations were performed successfully</returns>
private bool AddAndPerformNestingOperations()
{
bool success = true;
// flip alternative roots -> mount map for easier lookup
var alternativeRoots = m_alternativeRoots.ToMultiValueDictionary(kvp => kvp.Value, kvp => kvp.Key);
// Collect here the mount roots of tokenizable mounts. The logic is:
// * System mounts are tokenizable.
// * Mounts that are descendants of a system mount are tokenizable
// Rationale: We don't tokenize all mounts because that can lead to incorrect fingerprinting. E.g. let's say a tool writes
// a path P in an output file, P is a descendant of a tokenized mount root M and the corresponding pip gets cached.
// If the pip is looked up on a machine where M is a different root M', then we can get a cache hit, whereas it should have been
// a miss because the tool would have produced an output file with a written path P'
// As a compromise solution, system mounts are deemed safe enough to tokenize because they tend to be stable enough and it is unlikely
// that tools embed system-related paths in produced files. Transitively, any non-system mount that has a
// system mount above should be equally safe.
var tokenizableMountRoots = new HashSet <AbsolutePath>();
// All system mount paths
var systemMounts = m_mountPathIdentifiersByMount.Keys.Where(mount => mount.IsSystem && mount.Path.IsValid).Select(mount => mount.Path).ToHashSet();
// Compute the depth of each mount root so parent mounts can be visited first
// As we go upwards, also verify if there is any parent mount that is a system one
List <KeyValuePair <int, IMount> > mountsByRootDepth = new List <KeyValuePair <int, IMount> >();
foreach (IMount mount in m_mountMapBuilder.Values)
{
int depth = 0;
AbsolutePath path = mount.Path;
while (path.IsValid)
{
// if a mount is defined in the same location of a system mount, or has a system mount somewhere above, then it is also tokenizable
if (systemMounts.Contains(path))
{
tokenizableMountRoots.Add(mount.Path);
}
path = path.GetParent(m_context.PathTable);
depth++;
}
mountsByRootDepth.Add(new KeyValuePair <int, IMount>(depth, mount));
}
mountsByRootDepth.Sort((depthAndMount1, depthAndMount2) => depthAndMount1.Key.CompareTo(depthAndMount2.Key));
foreach (var mountEntry in mountsByRootDepth)
{
var childMount = mountEntry.Value;
var parentMountInfo = MountPathExpander.GetSemanticPathInfo(childMount.Path);
if (parentMountInfo.IsValid)
{
IMount parentMount;
if (!m_mountMapBuilder.TryGetValue(parentMountInfo.Root, out parentMount) && m_parent != null)
{
parentMount = m_parent.m_mountMapBuilder[parentMountInfo.Root];
}
if (parentMount.IsScrubbable && !childMount.IsScrubbable)
{
LogRelatedMountError(
Logger.Log.ScrubbableMountsMayOnlyContainScrubbableMounts,
childMount: childMount,
parentMount: parentMount);
success = false;
}
}
// TODO: Does not adding on success == false change behavior
if (success)
{
MountPathExpander.Add(m_context.PathTable, childMount, isTokenizable: tokenizableMountRoots.Contains(childMount.Path));
if (alternativeRoots.TryGetValue(childMount, out var additionalRoots))
{
foreach (var root in additionalRoots)
{
MountPathExpander.AddWithExistingName(
m_context.PathTable,
new SemanticPathInfo(
childMount.Name,
root,
childMount.TrackSourceFileChanges,
childMount.IsReadable,
childMount.IsWritable,
childMount.IsSystem,
childMount.IsStatic,
childMount.IsScrubbable,
childMount.AllowCreateDirectory,
tokenizable: tokenizableMountRoots.Contains(root)));
}
}
}
}
return(success);
}