Escape regex-relevant characters in test filter

Go tests can contain arbitrary characters because they're not tied to a
symbol name in a source file. Accordingly, they may contain characters
which have special meaning for regexes. Because the Go test runner
interprets this flag as a regex, we need to escape these.

Without this, running a single test from the gutter, Bazel will exit 0
and look happy, but it won't have actually run the test (which perhaps
would have failed if it had run).

golang/src/com/google/idea/blaze/golang/run/producers/GoTestContextProvider.java

@@ -19,6 +19,7 @@
 import com.goide.execution.testing.GoTestRunConfigurationProducerBase;
 import com.goide.psi.GoFile;
 import com.goide.psi.GoFunctionOrMethodDeclaration;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.idea.blaze.base.dependencies.TargetInfo;
 import com.google.idea.blaze.base.run.ExecutorType;
@@ -47,18 +48,43 @@ class GoTestContextProvider implements TestContextProvider {
    * When a user clicks in the ">" button, we get pointed to the "Run" part of "t.Run".
    * We need to walk the tree up to see the function call that has the actual argument.
    *
+   * This function doesn't worry about turning this filter into a regex which can be passed to --test_filter.
+   * @see #regexifyTestFilter for converting this to a --test_filter value.
+   *
    * @param element: Element the user has clicked on.
    * @param enclosingFunction: Go function encompassing this test.
    * @return String representation of the proper test filter.
    */
-  private String calculateTestFilter(PsiElement element, GoFunctionOrMethodDeclaration enclosingFunction) {
+  private static String calculateRawTestFilterForElement(PsiElement element, GoFunctionOrMethodDeclaration enclosingFunction) {
     if (element.getParent().isEquivalentTo(enclosingFunction)) {
       return enclosingFunction.getName();
     } else {
       return GoTestRunConfigurationProducerBase.findSubTestInContext(element, enclosingFunction);
     }
   }
 
+  @VisibleForTesting
+  static String regexifyTestFilter(String testFilter) {
+    return "^" + escapeRegexChars(testFilter) + "$";
+  }
+
+  private static String escapeRegexChars(String name) {
+    StringBuilder output = new StringBuilder();
+    for (char c : name.toCharArray()) {
+      if (isRegexCharNeedingEscaping(c)) {
+        output.append("\\");
+      }
+      output.append(c);
+    }
+    return output.toString();
+  }
+
+  private static boolean isRegexCharNeedingEscaping(char c) {
+    // Taken from https://cs.opensource.google/go/go/+/refs/tags/go1.21.4:src/regexp/regexp.go;l=720
+    return c == '\\' || c == '.' || c == '+' || c == '*' || c == '?' || c == '(' || c == ')' || c == '|' || c == '[' || c == ']' || c == '{' || c == '}' || c == '^' || c == '$';
+  }
+
+
   public static final String GO_TEST_WRAP_TESTV = "GO_TEST_WRAP_TESTV=1";
   @Nullable
   @Override
@@ -84,11 +110,11 @@ public RunConfigurationContext getTestContext(ConfigurationContext context) {
           .setDescription(file.getName())
           .build();
     }
-    String testFilter = calculateTestFilter(element, function);
+    String testFilterRegex = regexifyTestFilter(calculateRawTestFilterForElement(element, function));
     return TestContext.builder(/* sourceElement= */ function, ExecutorType.DEBUG_SUPPORTED_TYPES)
         .addTestEnv(GO_TEST_WRAP_TESTV)
         .setTarget(target)
-        .setTestFilter("^" + testFilter + "$")
+        .setTestFilter(testFilterRegex)
         .setDescription(String.format("%s#%s", file.getName(), function.getName()))
         .build();
   }

golang/tests/integrationtests/com/google/idea/blaze/golang/run/producers/BlazeGoTestConfigurationProducerTest.java

@@ -155,12 +155,14 @@ public void testNestedTests() throws Throwable {
         "func TestFoo(t *testing.T) {",
         "   t.R<caret>un(\"with_nested\", func(t *testing.T) {",
         "     t.R<caret>un(\"subtest\", func(t *testing.T) {})",
+        "     t.R<caret>un(\"subtest (great)\", func(t *testing.T) {})",
         "   })",
         "}"
     );
 
     assertElementGeneratesTestFilter(getElementAtCaret(0, goFile), "^TestFoo/with_nested$");
     assertElementGeneratesTestFilter(getElementAtCaret(1, goFile), "^TestFoo/with_nested/subtest$");
+    assertElementGeneratesTestFilter(getElementAtCaret(2, goFile), "^TestFoo/with_nested/subtest_\\(great\\)$");
   }
   @Test
   public void testCodeBetweenTests() throws Throwable {

golang/tests/unittests/com/google/idea/blaze/golang/run/producers/GoTestContextProviderTest.java

@@ -0,0 +1,17 @@
+package com.google.idea.blaze.golang.run.producers;
+
+import com.google.idea.blaze.base.BlazeTestCase;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import static com.google.common.truth.Truth.assertThat;
+
+@RunWith(JUnit4.class)
+public class GoTestContextProviderTest extends BlazeTestCase {
+    @Test
+    public void testRegexifyTestFilter() {
+        String regexified = GoTestContextProvider.regexifyTestFilter("Test/with/subtest(good \\ or \\ bad)");
+        assertThat(regexified).isEqualTo("^Test/with/subtest\\(good \\\\ or \\\\ bad\\)$");
+    }
+}