From 886ed1ccf38715dbae587ce6d6e736809bf73d4f Mon Sep 17 00:00:00 2001
From: David Schlosnagle <schlosna@gmail.com>
Date: Fri, 8 Jan 2021 12:16:36 -0800
Subject: [PATCH] Handle diagnostics without source

In some cases, compiler diagnostics may not have an associated source,
and for testing whether suggested fixes compile these should be treated
as originating from the same compilation unit of the suggested fix.

Fixes #1873

Fixes #2064

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/error-prone/pull/2064 from schlosna:ds/1873-SuggestedFixes-NPE ddd042bafb598c84561cd27dddc9a25eef5c7051
PiperOrigin-RevId: 350812718
---
 .../main/java/com/google/errorprone/fixes/SuggestedFixes.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java b/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
index 439b60676f6..5626d92f8f8 100644
--- a/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
+++ b/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
@@ -1309,8 +1309,10 @@ public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOExcept
     boolean warningInSameCompilationUnit = false;
     for (Diagnostic<? extends JavaFileObject> diagnostic : diagnosticListener.getDiagnostics()) {
       warningIsError |= diagnostic.getCode().equals("compiler.err.warnings.and.werror");
+      JavaFileObject diagnosticSource = diagnostic.getSource();
+      // If the source's origin is unknown, assume that new diagnostics are due to a modification.
       boolean diagnosticInSameCompilationUnit =
-          diagnostic.getSource().toUri().equals(modifiedFileUri);
+          diagnosticSource == null || diagnosticSource.toUri().equals(modifiedFileUri);
       switch (diagnostic.getKind()) {
         case ERROR:
           ++countErrors;