Skylark: ctx.actions.run_shell uses helper script

If the shell command in
ctx.actions.run_shell.command is longer than the
platform's shell's limit, Bazel will dump the
command to a helper shell script and execute that
script in the run_shell action.

Genrules also write a helper script when
genrule.cmd is longer than the shell's limit, and
ctx.actions.run_shell now uses the same machinery.

Fixes https://github.com/bazelbuild/bazel/issues/3589

Change-Id: Ib24dce90182ef69552deb2d400e00ae061537309
PiperOrigin-RevId: 167126560

2 files changed, 48 insertions, 5 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
index 70afd0f1b3..330c017a1d 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
@@ -246,6 +246,27 @@ public final class CommandHelper {
   }
 
   /**
+   * If {@code command} is too long, creates a helper shell script that runs that command.
+   *
+   * <p>Returns the {@link Artifact} corresponding to that script.
+   *
+   * <p>Otherwise, when {@code command} is shorter than the platform's shell's command length limit,
+   * this method does nothing and returns null.
+   */
+  @Nullable
+  public static Artifact shellCommandHelperScriptMaybe(
+      RuleContext ruleCtx,
+      String command,
+      String scriptPostFix,
+      Map<String, String> executionInfo) {
+    if (command.length() <= maxCommandLength) {
+      return null;
+    } else {
+      return buildCommandLineArtifact(ruleCtx, command, scriptPostFix);
+    }
+  }
+
+  /**
    * Builds the set of command-line arguments. Creates a bash script if the
    * command line is longer than the allowed maximum {@link #maxCommandLength}.
    * Fixes up the input artifact list with the created bash script when required.
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
index 88080e05eb..2433cdb6c7 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkActionFactory.java
@@ -20,6 +20,7 @@ import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.Root;
 import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.extra.SpawnInfo;
+import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
 import com.google.devtools.build.lib.analysis.PseudoAction;
 import com.google.devtools.build.lib.analysis.RuleContext;
@@ -34,6 +35,7 @@ import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.packages.TargetUtils;
 import com.google.devtools.build.lib.skylarkinterface.Param;
 import com.google.devtools.build.lib.skylarkinterface.ParamType;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
@@ -72,6 +74,8 @@ public class SkylarkActionFactory implements SkylarkValue {
   private final SkylarkRuleContext context;
   private final SkylarkSemanticsOptions skylarkSemanticsOptions;
   private RuleContext ruleContext;
+  /** Counter for actions.run_shell helper scripts. Every script must have a unique name. */
+  private int runShellOutputCounter = 0;
 
   public SkylarkActionFactory(
       SkylarkRuleContext context,
@@ -573,7 +577,23 @@ public class SkylarkActionFactory implements SkylarkValue {
     }
 
     if (commandUnchecked instanceof String) {
-      builder.setShellCommand((String) commandUnchecked);
+      Map<String, String> executionInfo =
+          ImmutableMap.copyOf(TargetUtils.getExecutionInfo(ruleContext.getRule()));
+      String helperScriptSuffix = String.format(".run_shell_%d.sh", runShellOutputCounter++);
+      String command = (String) commandUnchecked;
+      Artifact helperScript =
+          CommandHelper.shellCommandHelperScriptMaybe(
+              ruleContext, command, helperScriptSuffix, executionInfo);
+      if (helperScript == null) {
+        builder.setShellCommand(command);
+      } else {
+        builder.setShellCommand(helperScript.getExecPathString());
+        builder.addInput(helperScript);
+        FilesToRunProvider provider = context.getExecutableRunfiles(helperScript);
+        if (provider != null) {
+          builder.addTool(provider);
+        }
+      }
     } else if (commandUnchecked instanceof SkylarkList) {
       SkylarkList commandList = (SkylarkList) commandUnchecked;
       if (commandList.size() < 3) {
@@ -601,18 +621,20 @@ public class SkylarkActionFactory implements SkylarkValue {
   }
 
   /**
-   * Stup for spawn actions common between {@link #run} and {@link #runShell}.
+   * Setup for spawn actions common between {@link #run} and {@link #runShell}.
    *
-   * {@code builder} should have either executable or a command set.
+   * <p>{@code builder} should have either executable or a command set.
    */
   private void registerSpawnAction(
       SkylarkList outputs,
       Object inputs,
       Object mnemonicUnchecked,
       Object progressMessage,
-      Boolean useDefaultShellEnv, Object envUnchecked,
+      Boolean useDefaultShellEnv,
+      Object envUnchecked,
       Object executionRequirementsUnchecked,
-      Object inputManifestsUnchecked, SpawnAction.Builder builder)
+      Object inputManifestsUnchecked,
+      SpawnAction.Builder builder)
       throws EvalException {
     // TODO(bazel-team): builder still makes unnecessary copies of inputs, outputs and args.
     Iterable<Artifact> inputArtifacts;