Enable Bazel commands to exit at any time.

This is the first step on a journey toward allowing commands to AbruptExit
wherever they please, similar to how the user can press Ctrl+C at any time
and we (should) bail out as fast as we can.

By interrupting the command's main thread, we at least offer the command
the ability to see that an error requiring a bail has happened, and it should
trigger at potentially more locations, rather than just between phases.

--
MOS_MIGRATED_REVID=135152330

1 files changed, 13 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/buildtool/BuildTool.java b/src/main/java/com/google/devtools/build/lib/buildtool/BuildTool.java
index 974a63228c..afdde3c365 100644
--- a/src/main/java/com/google/devtools/build/lib/buildtool/BuildTool.java
+++ b/src/main/java/com/google/devtools/build/lib/buildtool/BuildTool.java
@@ -342,9 +342,19 @@ public final class BuildTool {
       }
       exitCode = e.getExitCode() != null ? e.getExitCode() : ExitCode.BUILD_FAILURE;
     } catch (InterruptedException e) {
-      exitCode = ExitCode.INTERRUPTED;
-      env.getReporter().handle(Event.error("build interrupted"));
-      env.getEventBus().post(new BuildInterruptedEvent());
+      // We may have been interrupted by an error, or the user's interruption may have raced with
+      // an error, so check to see if we should report that error code instead.
+      exitCode = env.getPendingExitCode();
+      if (exitCode == null) {
+        exitCode = ExitCode.INTERRUPTED;
+        env.getReporter().handle(Event.error("build interrupted"));
+        env.getEventBus().post(new BuildInterruptedEvent());
+      } else {
+        // Report the exception from the environment - the exception we're handling here is just an
+        // interruption.
+        reportExceptionError(env.getPendingException());
+        result.setCatastrophe();
+      }
     } catch (TargetParsingException | LoadingFailedException | ViewCreationFailedException e) {
       exitCode = ExitCode.PARSING_FAILURE;
       reportExceptionError(e);