Make a 'did you mean' suggestion when referencing a non-existent label.

It works for both labels on the command-line and labels in BUILD files.

--
MOS_MIGRATED_REVID=123967347

4 files changed, 32 insertions, 4 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/packages/ExportsFilesTest.java b/src/test/java/com/google/devtools/build/lib/packages/ExportsFilesTest.java
index c8afeea69a..31ca540590 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/ExportsFilesTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/ExportsFilesTest.java
@@ -75,7 +75,8 @@ public class ExportsFilesTest {
       fail();
     } catch (NoSuchTargetException e) {
       assertThat(e).hasMessage("no such target '//pkg:baz.txt':"
-          + " target 'baz.txt' not declared in package 'pkg' defined by /workspace/pkg/BUILD");
+          + " target 'baz.txt' not declared in package 'pkg' (did you mean 'bar.txt'?)"
+          + " defined by /workspace/pkg/BUILD");
     }
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/packages/PackageFactoryTest.java b/src/test/java/com/google/devtools/build/lib/packages/PackageFactoryTest.java
index cefcf1592e..943c21f929 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/PackageFactoryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/PackageFactoryTest.java
@@ -500,7 +500,8 @@ public class PackageFactoryTest extends PackageFactoryTestBase {
       assertThat(e)
           .hasMessage(
               "no such target '//x:z.cc': "
-                  + "target 'z.cc' not declared in package 'x' defined by /x/BUILD");
+                  + "target 'z.cc' not declared in package 'x' (did you mean 'x.cc'?) "
+                  + "defined by /x/BUILD");
     }
 
     try {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorTest.java
index c99a5822b5..aeb297e486 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorTest.java
@@ -316,7 +316,7 @@ public class TargetPatternEvaluatorTest extends AbstractTargetPatternEvaluatorTe
   @Test
   public void testUnsupportedTargets() throws Exception {
     String expectedError = "no such target '//foo:foo': target 'foo' not declared in package 'foo'"
-        + " defined by /workspace/foo/BUILD";
+        + " (did you mean 'foo1'?) defined by /workspace/foo/BUILD";
     expectError(expectedError, "foo");
     expectError("The package part of 'foo/' should not end in a slash", "foo/");
   }
@@ -1155,4 +1155,3 @@ public class TargetPatternEvaluatorTest extends AbstractTargetPatternEvaluatorTe
     expectError("no such target '//:nope.cc'", "//:nope.cc");
   }
 }
-
diff --git a/src/test/java/com/google/devtools/build/lib/util/SpellCheckerTest.java b/src/test/java/com/google/devtools/build/lib/util/SpellCheckerTest.java
index d0d84e38f6..5b4e55d4df 100644
--- a/src/test/java/com/google/devtools/build/lib/util/SpellCheckerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/SpellCheckerTest.java
@@ -15,10 +15,14 @@ package com.google.devtools.build.lib.util;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.common.collect.Lists;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
+import java.util.List;
+
 /**
  * Tests for {@link SpellChecker}.
  */
@@ -76,4 +80,27 @@ public class SpellCheckerTest {
 
     assertThat(SpellChecker.editDistance("abcdefg", "s", 2)).isEqualTo(-1);
   }
+
+  @Test
+  public void suggest() throws Exception {
+    List<String> dict = Lists.newArrayList(
+        "isalnum", "isalpha", "isdigit", "islower", "isupper", "find", "join",
+        "rsplit", "rstrip", "split", "splitlines", "startswith", "strip", "title", "upper");
+
+    assertThat(SpellChecker.suggest("isdfit", dict)).isEqualTo("isdigit");
+    assertThat(SpellChecker.suggest("rspit", dict)).isEqualTo("rsplit");
+    assertThat(SpellChecker.suggest("IS_LOWER", dict)).isEqualTo("islower");
+    assertThat(SpellChecker.suggest("sartwigh", dict)).isEqualTo("startswith");
+    assertThat(SpellChecker.suggest("SplitAllLines", dict)).isEqualTo("splitlines");
+    assertThat(SpellChecker.suggest("fird", dict)).isEqualTo("find");
+    assertThat(SpellChecker.suggest("stip", dict)).isEqualTo("strip");
+    assertThat(SpellChecker.suggest("isAln", dict)).isEqualTo("isalnum");
+
+    assertThat(SpellChecker.suggest("isAl", dict)).isEqualTo(null);
+    assertThat(SpellChecker.suggest("", dict)).isEqualTo(null);
+    assertThat(SpellChecker.suggest("f", dict)).isEqualTo(null);
+    assertThat(SpellChecker.suggest("fir", dict)).isEqualTo(null);
+    assertThat(SpellChecker.suggest("wqevxc", dict)).isEqualTo(null);
+    assertThat(SpellChecker.suggest("ialsnuaip", dict)).isEqualTo(null);
+  }
 }