From b86ef4211ef728f7de2cca58d8cc371442b615d9 Mon Sep 17 00:00:00 2001
From: Fabian Meumertzheim <fabian@meumertzhe.im>
Date: Fri, 25 Oct 2024 17:35:19 +0200
Subject: [PATCH] Skip over runfiles middleman artifacts without a
 RunfilesSupplier (#24086)

Fixes #24061
---
 .../lib/exec/CompactSpawnLogContext.java      | 10 +++++++++
 src/test/shell/bazel/bazel_execlog_test.sh    | 21 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/main/java/com/google/devtools/build/lib/exec/CompactSpawnLogContext.java b/src/main/java/com/google/devtools/build/lib/exec/CompactSpawnLogContext.java
index d9e57dc56ae646..936ce0f11e85b8 100644
--- a/src/main/java/com/google/devtools/build/lib/exec/CompactSpawnLogContext.java
+++ b/src/main/java/com/google/devtools/build/lib/exec/CompactSpawnLogContext.java
@@ -399,6 +399,16 @@ private int logInputSet(
           for (ActionInput input : set.getLeaves()) {
             if (input instanceof Artifact artifact && artifact.isMiddlemanArtifact()) {
               RunfilesTree runfilesTree = runfilesTrees.get(artifact);
+              if (runfilesTree == null) {
+                // This happens for spawns that don't keep their RunfilesSuppliers in sync with
+                // the middleman artifacts in their inputs.
+                // The known examples are test spawns that include the lcov merger as a middleman
+                // artifact, but don't merge in its supplier, as well as split coverage
+                // postprocessing spawns, which include the test runfiles middleman but not its
+                // supplier. Since the supplier is what causes the runfiles tree to be materialized,
+                // we can safely ignore these stray middleman artifacts.
+                continue;
+              }
               builder.addInputIds(
                   logRunfilesTree(
                       runfilesTree, inputMetadataProvider, fileSystem, isTestRunnerSpawn));
diff --git a/src/test/shell/bazel/bazel_execlog_test.sh b/src/test/shell/bazel/bazel_execlog_test.sh
index 660fb1639d2293..b2418a5fa2fd72 100755
--- a/src/test/shell/bazel/bazel_execlog_test.sh
+++ b/src/test/shell/bazel/bazel_execlog_test.sh
@@ -203,6 +203,27 @@ EOF
   [[ -e ../output.compact ]] || fail "no compact log produced"
 }
 
+function test_coverage() {
+  cat > BUILD <<'EOF'
+sh_test(
+    name = "test",
+    srcs = ["test.sh"],
+)
+EOF
+  cat > test.sh <<'EOF'
+echo "hello world"
+EOF
+  chmod +x test.sh
+
+  bazel coverage //:test --execution_log_compact_file=output.compact >> $TEST_log 2>&1 || fail "coverage failed"
+  [[ -e output.compact ]] || fail "no compact log produced"
+
+  rm output.compact
+  bazel coverage //:test --experimental_split_coverage_postprocessing --experimental_fetch_all_coverage_outputs \
+    --execution_log_compact_file=output.compact >> $TEST_log 2>&1 || fail "coverage failed"
+  [[ -e output.compact ]] || fail "no compact log produced"
+}
+
 function test_no_remote_cache() {
   cat > BUILD <<'EOF'
 genrule(