internal/lsp/cache: invalidate packages with missing deps when files are

added

Add logic to invalidate any packages with missing dependencies when a
file is added.

Also fix a latent bug overwriting 'anyFileOpenenedOrClosed' for each
loop iteration.

Fixes golang/go#54073

Change-Id: I000ceb354885bd4863a1dfdda09e4d5f0e5481f3
Reviewed-on: https://go-review.googlesource.com/c/tools/+/419501
Run-TryBot: Robert Findley <[email protected]>
Reviewed-by: Suzy Mueller <[email protected]>
gopls-CI: kokoro <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

gopls/internal/regtest/watch/watch_test.go

@@ -199,14 +199,12 @@ func _() {
 }
 `
 	Run(t, missing, func(t *testing.T, env *Env) {
-		t.Skip("the initial workspace load fails and never retries")
-
 		env.Await(
 			env.DiagnosticAtRegexp("a/a.go", "\"mod.com/c\""),
 		)
 		env.WriteWorkspaceFile("c/c.go", `package c; func C() {};`)
 		env.Await(
-			EmptyDiagnostics("c/c.go"),
+			EmptyDiagnostics("a/a.go"),
 		)
 	})
 }

internal/lsp/cache/snapshot.go

@@ -1695,8 +1695,10 @@ func (s *snapshot) clone(ctx, bgCtx context.Context, changes map[span.URI]*fileC
 
 	// Compute invalidations based on file changes.
 	changedPkgFiles := map[PackageID]bool{} // packages whose file set may have changed
-	anyImportDeleted := false
-	anyFileOpenedOrClosed := false
+	anyImportDeleted := false               // import deletions can resolve cycles
+	anyFileOpenedOrClosed := false          // opened files affect workspace packages
+	anyFileAdded := false                   // adding a file can resolve missing dependencies
+
 	for uri, change := range changes {
 		// Maybe reinitialize the view if we see a change in the vendor
 		// directory.
@@ -1709,7 +1711,8 @@ func (s *snapshot) clone(ctx, bgCtx context.Context, changes map[span.URI]*fileC
 		var originalOpen, newOpen bool
 		_, originalOpen = originalFH.(*overlay)
 		_, newOpen = change.fileHandle.(*overlay)
-		anyFileOpenedOrClosed = originalOpen != newOpen
+		anyFileOpenedOrClosed = anyFileOpenedOrClosed || (originalOpen != newOpen)
+		anyFileAdded = anyFileAdded || (originalFH == nil && change.fileHandle != nil)
 
 		// If uri is a Go file, check if it has changed in a way that would
 		// invalidate metadata. Note that we can't use s.view.FileKind here,
@@ -1779,6 +1782,19 @@ func (s *snapshot) clone(ctx, bgCtx context.Context, changes map[span.URI]*fileC
 		}
 	}
 
+	// Adding a file can resolve missing dependencies from existing packages.
+	//
+	// We could be smart here and try to guess which packages may have been
+	// fixed, but until that proves necessary, just invalidate metadata for any
+	// package with missing dependencies.
+	if anyFileAdded {
+		for id, metadata := range s.meta.metadata {
+			if len(metadata.MissingDeps) > 0 {
+				directIDs[id] = true
+			}
+		}
+	}
+
 	// Invalidate reverse dependencies too.
 	// idsToInvalidate keeps track of transitive reverse dependencies.
 	// If an ID is present in the map, invalidate its types.