Fix bug when vendor is incremental and client is not (#460)

Author: David Ungar

Sources/SwiftDriver/IncrementalCompilation/ModuleDependencyGraphParts/Integrator.swift

@@ -219,8 +219,9 @@ extension ModuleDependencyGraph.Integrator {
         .contains(externalDependency)
       guard !isKnown else {return}
       if !isIncremental {
-        destination.reporter?.report("found externalDependency",
-                                     externalDependency.file)
+        // Nice for debugging, but too much otherwise:
+        // destination.reporter?.report("found externalDependency", externalDependency.file)
+        
         // no integration to do for these, so just remember them here
         destination.externalDependencies.insert(externalDependency)
       }
@@ -233,7 +234,7 @@ extension ModuleDependencyGraph.Integrator {
           aspect: .interface,
           designator: .externalDepend(externalDependency))
         let isNewUse = destination.nodeFinder.record(def: key, use: moduleUseNode)
-        if !isNewUse {
+        if isNewUse {
           destination.externalDependencies.insert(externalDependency)
           results.changedNodes.insert(moduleUseNode)
         }

Tests/SwiftDriverTests/IncrementalCompilationTests.swift

@@ -454,8 +454,6 @@ final class IncrementalCompilationTests: XCTestCase {
       checkDiagnostics: checkDiagnostics,
       expectingRemarks: [
         "Disabling incremental cross-module building",
-        "Incremental compilation: found externalDependency",
-        "Incremental compilation: found externalDependency",
         "Incremental compilation: May skip current input:  {compile: main.o <= main.swift}",
         "Incremental compilation: May skip current input:  {compile: other.o <= other.swift}",
         "Incremental compilation: Skipping input:  {compile: main.o <= main.swift}",
@@ -472,8 +470,6 @@ final class IncrementalCompilationTests: XCTestCase {
       checkDiagnostics: checkDiagnostics,
       expectingRemarks: [
         "Disabling incremental cross-module building",
-        "Incremental compilation: found externalDependency",
-        "Incremental compilation: found externalDependency",
         "Incremental compilation: May skip current input:  {compile: main.o <= main.swift}",
         "Incremental compilation: Scheduing changed input  {compile: other.o <= other.swift}",
         "Incremental compilation: Queuing (initial):  {compile: other.o <= other.swift}",
@@ -499,8 +495,6 @@ final class IncrementalCompilationTests: XCTestCase {
       checkDiagnostics: checkDiagnostics,
       expectingRemarks: [
         "Disabling incremental cross-module building",
-        "Incremental compilation: found externalDependency",
-        "Incremental compilation: found externalDependency",
         "Incremental compilation: Scheduing changed input  {compile: main.o <= main.swift}",
         "Incremental compilation: Scheduing changed input  {compile: other.o <= other.swift}",
         "Incremental compilation: Queuing (initial):  {compile: main.o <= main.swift}",
@@ -527,8 +521,6 @@ final class IncrementalCompilationTests: XCTestCase {
       checkDiagnostics: checkDiagnostics,
       expectingRemarks: [
         "Disabling incremental cross-module building",
-        "Incremental compilation: found externalDependency",
-        "Incremental compilation: found externalDependency",
         "Incremental compilation: Scheduing changed input  {compile: main.o <= main.swift}",
         "Incremental compilation: May skip current input:  {compile: other.o <= other.swift}",
         "Incremental compilation: Queuing (initial):  {compile: main.o <= main.swift}",
@@ -564,8 +556,6 @@ final class IncrementalCompilationTests: XCTestCase {
       extraArguments: [extraArgument],
       expectingRemarks: [
         "Disabling incremental cross-module building",
-        "Incremental compilation: found externalDependency",
-        "Incremental compilation: found externalDependency",
         "Incremental compilation: May skip current input:  {compile: other.o <= other.swift}",
         "Incremental compilation: Queuing (initial):  {compile: main.o <= main.swift}",
         "Incremental compilation: scheduling dependents of main.swift; -driver-always-rebuild-dependents",