fix: issue-5850 - Settle override conflicts between edges and propagate changes

workspaces/arborist/lib/dep-valid.js

@@ -101,7 +101,7 @@ const depValid = (child, requested, requestor) => {
       })
     }
 
-    default: // unpossible, just being cautious
+    default: // impossible, just being cautious
       break
   }
 

workspaces/arborist/lib/edge.js

@@ -4,6 +4,7 @@
 const util = require('node:util')
 const npa = require('npm-package-arg')
 const depValid = require('./dep-valid.js')
+const OverrideSet = require('./override-set.js')
 
 class ArboristEdge {
   constructor (edge) {
@@ -103,7 +104,7 @@ class Edge {
   }
 
   satisfiedBy (node) {
-    if (node.name !== this.#name) {
+    if (node.name !== this.#name || !this.#from) {
       return false
     }
 
@@ -112,7 +113,31 @@ class Edge {
     if (node.hasShrinkwrap || node.inShrinkwrap || node.inBundle) {
       return depValid(node, this.rawSpec, this.#accept, this.#from)
     }
-    return depValid(node, this.spec, this.#accept, this.#from)
+
+    // If there's no override we just use the spec.
+    if (!this.overrides?.keySpec) {
+      return depValid(node, this.spec, this.#accept, this.#from)
+    }
+    // There's some override. If the target node satisfies the overriding spec
+    // then it's okay.
+    if (depValid(node, this.spec, this.#accept, this.#from)) {
+      return true
+    }
+    // If it doesn't, then it should at least satisfy the original spec.
+    if (!depValid(node, this.rawSpec, this.#accept, this.#from)) {
+      return false
+    }
+    // It satisfies the original spec, not the overriding spec. We need to make
+    // sure it doesn't use the overridden spec.
+    // For example:
+    //   we might have an ^8.0.0 rawSpec, and an override that makes
+    //   keySpec=8.23.0 and the override value spec=9.0.0.
+    //   If the node is 9.0.0, then it's okay because it's consistent with spec.
+    //   If the node is 8.24.0, then it's okay because it's consistent with the rawSpec.
+    //   If the node is 8.23.0, then it's not okay because even though it's consistent
+    //   with the rawSpec, it's also consistent with the keySpec.
+    //   So we're looking for ^8.0.0 or 9.0.0 and not 8.23.0.
+    return !depValid(node, this.overrides.keySpec, this.#accept, this.#from)
   }
 
   // return the edge data, and an explanation of how that edge came to be here
@@ -181,11 +206,9 @@ class Edge {
     if (this.overrides?.value && this.overrides.value !== '*' && this.overrides.name === this.#name) {
       if (this.overrides.value.startsWith('$')) {
         const ref = this.overrides.value.slice(1)
-        // we may be a virtual root, if we are we want to resolve reference overrides
-        // from the real root, not the virtual one
-        const pkg = this.#from.sourceReference
-          ? this.#from.sourceReference.root.package
-          : this.#from.root.package
+        const pkg = this.#from?.sourceReference
+          ? this.#from?.sourceReference.root.package
+          : this.#from?.root?.package
         if (pkg.devDependencies?.[ref]) {
           return pkg.devDependencies[ref]
         }
@@ -234,10 +257,15 @@ class Edge {
         } else {
           this.#error = 'MISSING'
         }
-      } else if (this.peer && this.#from === this.#to.parent && !this.#from.isTop) {
+      } else if (this.peer && this.#from === this.#to.parent && !this.#from?.isTop) {
         this.#error = 'PEER LOCAL'
       } else if (!this.satisfiedBy(this.#to)) {
         this.#error = 'INVALID'
+      } else if (this.overrides && this.#to.edgesOut.size && OverrideSet.doOverrideSetsConflict(this.overrides, this.#to.overrides)) {
+        // Any inconsistency between the edge's override set and the target's override set is potentially problematic.
+        // But we only say the edge is in error if the override sets are plainly conflicting.
+        // Note that if the target doesn't have any dependencies of their own, then this inconsistency is irrelevant.
+        this.#error = 'INVALID'
       } else {
         this.#error = 'OK'
       }
@@ -250,15 +278,26 @@ class Edge {
 
   reload (hard = false) {
     this.#explanation = null
-    if (this.#from.overrides) {
-      this.overrides = this.#from.overrides.getEdgeRule(this)
+
+    let needToUpdateOverrideSet = false
+    let newOverrideSet
+    let oldOverrideSet
+    if (this.#from?.overrides) {
+      newOverrideSet = this.#from.overrides.getEdgeRule(this)
+      if (newOverrideSet && !newOverrideSet.isEqual(this.overrides)) {
+        // If there's a new different override set we need to propagate it to the nodes.
+        // If we're deleting the override set then there's no point propagating it right now since it will be filled with another value later.
+        needToUpdateOverrideSet = true
+        oldOverrideSet = this.overrides
+        this.overrides = newOverrideSet
+      }
     } else {
       delete this.overrides
     }
-    const newTo = this.#from.resolve(this.#name)
+    const newTo = this.#from?.resolve(this.#name)
     if (newTo !== this.#to) {
       if (this.#to) {
-        this.#to.edgesIn.delete(this)
+        this.#to.deleteEdgeIn(this)
       }
       this.#to = newTo
       this.#error = null
@@ -267,15 +306,19 @@ class Edge {
       }
     } else if (hard) {
       this.#error = null
+    } else if (needToUpdateOverrideSet && this.#to) {
+      // Propagate the new override set to the target node.
+      this.#to.updateOverridesEdgeInRemoved(oldOverrideSet)
+      this.#to.updateOverridesEdgeInAdded(newOverrideSet)
     }
   }
 
   detach () {
     this.#explanation = null
     if (this.#to) {
-      this.#to.edgesIn.delete(this)
+      this.#to.deleteEdgeIn(this)
     }
-    this.#from.edgesOut.delete(this.#name)
+    this.#from?.edgesOut.delete(this.#name)
     this.#to = null
     this.#error = 'DETACHED'
     this.#from = null

workspaces/arborist/lib/node.js

@@ -40,6 +40,7 @@ const debug = require('./debug.js')
 const gatherDepSet = require('./gather-dep-set.js')
 const treeCheck = require('./tree-check.js')
 const { walkUp } = require('walk-up-path')
+const { log } = require('proc-log')
 
 const { resolve, relative, dirname, basename } = require('node:path')
 const util = require('node:util')
@@ -344,7 +345,28 @@ class Node {
   }
 
   get overridden () {
-    return !!(this.overrides && this.overrides.value && this.overrides.name === this.name)
+    if (!this.overrides) {
+      return false
+    }
+    if (!this.overrides.value) {
+      return false
+    }
+    if (this.overrides.name !== this.name) {
+      return false
+    }
+
+    // The overrides rule is for a package with this name, but some override rules only apply to specific
+    // versions. To make sure this package was actually overridden, we check whether any edge going in
+    // had the rule applied to it, in which case its overrides set is different than its source node.
+    for (const edge of this.edgesIn) {
+      if (edge.overrides && edge.overrides.name === this.name && edge.overrides.value === this.version) {
+        if (!edge.overrides.isEqual(edge.from.overrides)) {
+          return true
+        }
+      }
+    }
+
+    return false
   }
 
   get package () {
@@ -822,9 +844,6 @@ class Node {
       target.root = root
     }
 
-    if (!this.overrides && this.parent && this.parent.overrides) {
-      this.overrides = this.parent.overrides.getNodeRule(this)
-    }
     // tree should always be valid upon root setter completion.
     treeCheck(this)
     if (this !== root) {
@@ -1006,10 +1025,21 @@ class Node {
       return false
     }
 
-    // XXX need to check for two root nodes?
-    if (node.overrides !== this.overrides) {
-      return false
+    // If this node has no dependencies, then it's irrelevant to check the override
+    // rules of the replacement node.
+    if (this.edgesOut.size) {
+      // XXX need to check for two root nodes?
+      if (node.overrides) {
+        if (!node.overrides.isEqual(this.overrides)) {
+          return false
+        }
+      } else {
+        if (this.overrides) {
+          return false
+        }
+      }
     }
+
     ignorePeers = new Set(ignorePeers)
 
     // gather up all the deps of this node and that are only depended
@@ -1077,8 +1107,13 @@ class Node {
       return false
     }
 
-    // if we prefer dedupe, or if the version is greater/equal, take the other
-    if (preferDedupe || semver.gte(other.version, this.version)) {
+    // if we prefer dedupe, or if the version is equal, take the other
+    if (preferDedupe || semver.eq(other.version, this.version)) {
+      return true
+    }
+
+    // if our current version isn't the result of an override, then prefer to take the greater version
+    if (!this.overridden && semver.gt(other.version, this.version)) {
       return true
     }
 
@@ -1249,10 +1284,6 @@ class Node {
       this[_changePath](newPath)
     }
 
-    if (parent.overrides) {
-      this.overrides = parent.overrides.getNodeRule(this)
-    }
-
     // clobbers anything at that path, resets all appropriate references
     this.root = parent.root
   }
@@ -1346,9 +1377,87 @@ class Node {
     this.edgesOut.set(edge.name, edge)
   }
 
-  addEdgeIn (edge) {
+  recalculateOutEdgesOverrides () {
+    // For each edge out propogate the new overrides through.
+    for (const edge of this.edgesOut.values()) {
+      edge.reload(true)
+      if (edge.to) {
+        edge.to.updateOverridesEdgeInAdded(edge.overrides)
+      }
+    }
+  }
+
+  updateOverridesEdgeInRemoved (otherOverrideSet) {
+    // If this edge's overrides isn't equal to this node's overrides, then removing it won't change newOverrideSet later.
+    if (!this.overrides || !this.overrides.isEqual(otherOverrideSet)) {
+      return false
+    }
+    let newOverrideSet
+    for (const edge of this.edgesIn) {
+      if (newOverrideSet && edge.overrides) {
+        newOverrideSet = OverrideSet.findSpecificOverrideSet(edge.overrides, newOverrideSet)
+      } else {
+        newOverrideSet = edge.overrides
+      }
+    }
+    if (this.overrides.isEqual(newOverrideSet)) {
+      return false
+    }
+    this.overrides = newOverrideSet
+    if (this.overrides) {
+      // Optimization: if there's any override set at all, then no non-extraneous node has an empty override set. So if we temporarily have no
+      // override set (for example, we removed all the edges in), there's no use updating all the edges out right now. Let's just wait until
+      // we have an actual override set later.
+      this.recalculateOutEdgesOverrides()
+    }
+    return true
+  }
+
+  // This logic isn't perfect either. When we have two edges in that have different override sets, then we have to decide which set is correct.
+  // This function assumes the more specific override set is applicable, so if we have dependencies A->B->C and A->C
+  // and an override set that specifies what happens for C under A->B, this will work even if the new A->C edge comes along and tries to change
+  // the override set.
+  // The strictly correct logic is not to allow two edges with different overrides to point to the same node, because even if this node can satisfy
+  // both, one of its dependencies might need to be different depending on the edge leading to it.
+  // However, this might cause a lot of duplication, because the conflict in the dependencies might never actually happen.
+  updateOverridesEdgeInAdded (otherOverrideSet) {
+    if (!otherOverrideSet) {
+      // Assuming there are any overrides at all, the overrides field is never undefined for any node at the end state of the tree.
+      // So if the new edge's overrides is undefined it will be updated later. So we can wait with updating the node's overrides field.
+      return false
+    }
+    if (!this.overrides) {
+      this.overrides = otherOverrideSet
+      this.recalculateOutEdgesOverrides()
+      return true
+    }
+    if (this.overrides.isEqual(otherOverrideSet)) {
+      return false
+    }
+    const newOverrideSet = OverrideSet.findSpecificOverrideSet(this.overrides, otherOverrideSet)
+    if (newOverrideSet) {
+      if (!this.overrides.isEqual(newOverrideSet)) {
+        this.overrides = newOverrideSet
+        this.recalculateOutEdgesOverrides()
+        return true
+      }
+      return false
+    }
+    // This is an error condition. We can only get here if the new override set is in conflict with the existing.
+    log.silly('Conflicting override sets', this.name)
+  }
+
+  deleteEdgeIn (edge) {
+    this.edgesIn.delete(edge)
     if (edge.overrides) {
-      this.overrides = edge.overrides
+      this.updateOverridesEdgeInRemoved(edge.overrides)
+    }
+  }
+
+  addEdgeIn (edge) {
+    // We need to handle the case where the new edge in has an overrides field which is different from the current value.
+    if (!this.overrides || !this.overrides.isEqual(edge.overrides)) {
+      this.updateOverridesEdgeInAdded(edge.overrides)
     }
 
     this.edgesIn.add(edge)