After a build action fails, stop printing more output.

Often the slow commands (errorprone happens to be particularly bad)
print a lot, so this should make it easier to find the error without
lots of scrolling.

This doesn't attempt to parse the output and re-display errors, so
if a command prints a thousand warnings with one error in the middle,
it'll still be hard to find the error.

Bug: 277114612
Test: cd build/soong/ui/terminal ; go test
Change-Id: I6c8285fc2c6e4fc345de57b2c15bc5e7d46b1d1f
diff --git a/ui/terminal/smart_status.go b/ui/terminal/smart_status.go
index 06a4064..3880b04 100644
--- a/ui/terminal/smart_status.go
+++ b/ui/terminal/smart_status.go
@@ -53,6 +53,13 @@
 	done            chan bool
 	sigwinch        chan os.Signal
 	sigwinchHandled chan bool
+
+	// Once there is a failure, we stop printing command output so the error
+	// is easier to find
+	haveFailures bool
+	// If we are dropping errors, then at the end, we report a message to go
+	// look in the verbose log if you want that command output.
+	postFailureActionCount int
 }
 
 // NewSmartStatusOutput returns a StatusOutput that represents the
@@ -165,12 +172,20 @@
 		}
 	}
 
+	s.statusLine(progress)
+
+	// Stop printing when there are failures, but don't skip actions that also have their own errors.
 	if output != "" {
-		s.statusLine(progress)
-		s.requestLine()
-		s.print(output)
-	} else {
-		s.statusLine(progress)
+		if !s.haveFailures || result.Error != nil {
+			s.requestLine()
+			s.print(output)
+		} else {
+			s.postFailureActionCount++
+		}
+	}
+
+	if result.Error != nil {
+		s.haveFailures = true
 	}
 }
 
@@ -187,6 +202,15 @@
 
 	s.stopSigwinch()
 
+	if s.postFailureActionCount > 0 {
+		s.requestLine()
+		if s.postFailureActionCount == 1 {
+			s.print(fmt.Sprintf("There was 1 action that completed after the action that failed. See verbose.log.gz for its output."))
+		} else {
+			s.print(fmt.Sprintf("There were %d actions that completed after the action that failed. See verbose.log.gz for their output.", s.postFailureActionCount))
+		}
+	}
+
 	s.requestLine()
 
 	s.runningActions = nil