Split the execution of the WORKSPACE file after each load statement

This is the main step toward supporting load statement of remote
repository in the WORKSPACE file (bug #824). Load statement that
refers to a remote repository will depend on the previous fragment
of the workspace file.

Issue #824 Step 3.

--
MOS_MIGRATED_REVID=114237027

1 files changed, 46 insertions, 16 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
index 305d2e89fc..2ab3267d87 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/WorkspaceFileFunction.java
@@ -14,15 +14,19 @@
 
 package com.google.devtools.build.lib.skyframe;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.packages.Package;
 import com.google.devtools.build.lib.packages.Package.LegacyBuilder;
+import com.google.devtools.build.lib.packages.Package.NameConflictException;
 import com.google.devtools.build.lib.packages.PackageFactory;
 import com.google.devtools.build.lib.packages.RuleClassProvider;
 import com.google.devtools.build.lib.packages.WorkspaceFactory;
 import com.google.devtools.build.lib.skyframe.PackageFunction.PackageFunctionException;
 import com.google.devtools.build.lib.skyframe.WorkspaceFileValue.WorkspaceFileKey;
 import com.google.devtools.build.lib.syntax.BuildFileAST;
+import com.google.devtools.build.lib.syntax.Environment.Extension;
 import com.google.devtools.build.lib.syntax.Mutability;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.RootedPath;
@@ -64,10 +68,20 @@ public class WorkspaceFileFunction implements SkyFunction {
 
     Path repoWorkspace = workspaceRoot.getRoot().getRelative(workspaceRoot.getRelativePath());
     LegacyBuilder builder =
-        com.google.devtools.build.lib.packages.Package.newExternalPackageBuilder(
-            repoWorkspace, ruleClassProvider.getRunfilesPrefix());
+        Package.newExternalPackageBuilder(repoWorkspace, ruleClassProvider.getRunfilesPrefix());
+
+    if (workspaceASTValue.getASTs().isEmpty()) {
+      return new WorkspaceFileValue(
+          builder.build(), // resulting package
+          ImmutableMap.<String, Extension>of(), // list of imports
+          ImmutableMap.<String, Object>of(), // list of symbol bindings
+          workspaceRoot, // Workspace root
+          0, // first fragment, idx = 0
+          false); // last fragment
+    }
+    WorkspaceFactory parser;
     try (Mutability mutability = Mutability.create("workspace %s", repoWorkspace)) {
-      WorkspaceFactory parser =
+      parser =
           new WorkspaceFactory(
               builder,
               ruleClassProvider,
@@ -75,23 +89,39 @@ public class WorkspaceFileFunction implements SkyFunction {
               mutability,
               directories.getEmbeddedBinariesRoot(),
               directories.getWorkspace());
-      try {
-        for (BuildFileAST ast : workspaceASTValue.getASTs()) {
-          PackageFunction.SkylarkImportResult importResult =
-              PackageFunction.fetchImportsFromBuildFile(
-                  repoWorkspace, Label.EXTERNAL_PACKAGE_IDENTIFIER, ast, env, null);
-          if (importResult != null) {
-            parser.execute(ast, importResult.importMap);
-          } else {
-            return null;
-          }
+      if (key.getIndex() > 0) {
+        WorkspaceFileValue prevValue =
+            (WorkspaceFileValue)
+                env.getValue(WorkspaceFileValue.key(key.getPath(), key.getIndex() - 1));
+        if (prevValue == null) {
+          return null;
         }
-      } catch (PackageFunctionException e) {
-        throw new WorkspaceFileFunctionException(e, Transience.PERSISTENT);
+        if (prevValue.next() == null) {
+          return prevValue;
+        }
+        parser.setParent(prevValue.getPackage(), prevValue.getImportMap(), prevValue.getBindings());
+      }
+      BuildFileAST ast = workspaceASTValue.getASTs().get(key.getIndex());
+      PackageFunction.SkylarkImportResult importResult =
+          PackageFunction.fetchImportsFromBuildFile(
+              repoWorkspace, Label.EXTERNAL_PACKAGE_IDENTIFIER, ast, env, null);
+      if (importResult == null) {
+        return null;
       }
+      // TODO(dmarting): give a nice error message when redefining a repository name and
+      // getIndex() > 0.
+      parser.execute(ast, importResult.importMap);
+    } catch (PackageFunctionException | NameConflictException e) {
+      throw new WorkspaceFileFunctionException(e, Transience.PERSISTENT);
     }
 
-    return new WorkspaceFileValue(builder.build(), workspaceRoot, 0, false);
+    return new WorkspaceFileValue(
+        builder.build(),
+        parser.getImportMap(),
+        parser.getVariableBindings(),
+        workspaceRoot,
+        key.getIndex(),
+        key.getIndex() < workspaceASTValue.getASTs().size() - 1);
   }
 
   @Override