From 74de0ba4e79341c77b8b85ff4485f92287b6854c Mon Sep 17 00:00:00 2001
From: Ulf Adams <ulf@engflow.com>
Date: Wed, 21 Apr 2021 10:44:09 -0700
Subject: [PATCH] Java coverage: fix handling of external files

When java_test rules are run with coverage, then Bazel writes a file
containing the runtime classpath using root-relative paths.

The collect_coverage.sh script then processes that file to generate
another file containing absolute paths by prefixing each of the paths
with the runfiles directory and the workspace name. It then runs the
singlejar tool on this list of jar files to merge them into a single
file.

This happens to work for all jar files in the main repository because
the runfiles path is the runfiles directory plus the workspace name
plus the root-relative path.

However, it is broken if some of the jar files come from an external
repository. It appears that singlejar errors out on the first such jar
file, generating a partial output jar file without a central directory.
The error is swallowed by the `collect_coverage.sh` script. Presence of
coverage results may thus depend on the order of classpath entries.

In order to fix this, we change the runtime classpath file to contain
runfiles-relative paths, and the coverage script to prefix them with
the runfiles directory.

Note that we reuse SourceManifestAction here, i.e., the identical code
that is also responsible for generating the runfiles directory in the
first place. This is the only reliable way to get the correct paths
into the test action.

There are more places that use `LazyWritePathsFileAction` and I suspect
that all of them are broken:

- persistent test runner support in BazelJavaSemantics (AFAIK, this
  doesn't work in Bazel anyway)
- coverage w/ metadata jars in BazelJavaSemantics (not used by
  JavaBinary)
- coverage source list file ('-paths-for-coverage.txt'); this probably
  results in non-functioning coverage for *source files* in external
  repositories

Fixes #13376.

Change-Id: Ie9bcc92344f06e190efcb192a3b6ef9905aea352

Closes #13377.

Change-Id: Ie9bcc92344f06e190efcb192a3b6ef9905aea352
PiperOrigin-RevId: 369687409
---
 .../build/lib/rules/java/JavaBinary.java      | 19 +++++++++++++------
 tools/test/collect_coverage.sh                |  2 +-
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
index 32ef49410a72a3..8d7a0d8ce219d7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
@@ -31,10 +31,11 @@
 import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
 import com.google.devtools.build.lib.analysis.RunfilesSupport;
+import com.google.devtools.build.lib.analysis.SourceManifestAction;
+import com.google.devtools.build.lib.analysis.SourceManifestAction.ManifestType;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
 import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
-import com.google.devtools.build.lib.analysis.actions.LazyWritePathsFileAction;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.analysis.config.CompilationMode;
 import com.google.devtools.build.lib.cmdline.Label;
@@ -429,19 +430,25 @@ public ConfiguredTarget create(RuleContext ruleContext)
     NestedSetBuilder<Artifact> coverageSupportFiles = NestedSetBuilder.stableOrder();
     if (ruleContext.getConfiguration().isCodeCoverageEnabled()) {
 
-      // Create an artifact that contains the root relative paths of the jars on the runtime
-      // classpath.
+      // Create an artifact that contains the runfiles relative paths of the jars on the runtime
+      // classpath. Using SourceManifestAction is the only reliable way to match the runfiles
+      // creation code.
       Artifact runtimeClasspathArtifact =
           ruleContext.getUniqueDirectoryArtifact(
               "runtime_classpath_for_coverage",
               "runtime_classpath.txt",
               ruleContext.getBinOrGenfilesDirectory());
       ruleContext.registerAction(
-          new LazyWritePathsFileAction(
+          new SourceManifestAction(
+              ManifestType.SOURCES_ONLY,
               ruleContext.getActionOwner(),
               runtimeClasspathArtifact,
-              common.getRuntimeClasspath(),
-              /* filesToIgnore= */ ImmutableSet.of(),
+              new Runfiles.Builder(
+                      ruleContext.getWorkspaceName(),
+                      ruleContext.getConfiguration().legacyExternalRunfiles())
+                  // This matches the code below in collectDefaultRunfiles.
+                  .addTransitiveArtifactsWrappedInStableOrder(common.getRuntimeClasspath())
+                  .build(),
               true));
       filesBuilder.add(runtimeClasspathArtifact);
 
diff --git a/tools/test/collect_coverage.sh b/tools/test/collect_coverage.sh
index 23d0198a21b727..25094d394110b0 100755
--- a/tools/test/collect_coverage.sh
+++ b/tools/test/collect_coverage.sh
@@ -140,7 +140,7 @@ if [[ ! -z "${JAVA_RUNTIME_CLASSPATH_FOR_COVERAGE}" ]]; then
   # Append the runfiles prefix to all the relative paths found in
   # JAVA_RUNTIME_CLASSPATH_FOR_COVERAGE, to invoke SingleJar with the
   # absolute paths.
-  RUNFILES_PREFIX="$TEST_SRCDIR/$TEST_WORKSPACE/"
+  RUNFILES_PREFIX="$TEST_SRCDIR/"
   cat "$JAVA_RUNTIME_CLASSPATH_FOR_COVERAGE" | sed "s@^@$RUNFILES_PREFIX@" >> "$single_jar_params_file"
 
   # Invoke SingleJar. This will create JACOCO_METADATA_JAR.