Windows, subprocesses: correct flag escaping impl.

    Add correct implementation of flag escaping for
    subprocesses.

    This is a follow-up to bazelbuild/bazel#7413

    Next steps:
    - replace WindowsProcesses.quoteCommandLine with
      the new logic

    See bazelbuild/bazel#7122

    Closes #7420.

    PiperOrigin-RevId: 233900149

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/shell/ShellUtils.java

@@ -142,4 +142,94 @@ public static void tokenize(List<String> options, String optionString)
     }
   }
 
+  /**
+   * Escape command line arguments for {@code CreateProcessW} on Windows.
+   *
+   * <p>This method implements the same algorithm as the native xx_binary launcher does (see
+   * https://github.com/bazelbuild/bazel/pull/7411).
+   *
+   * <p>A similar algorithm with lots of background information is described here:
+   * https://blogs.msdn.microsoft.com/twistylittlepassagesallalike/2011/04/23/
+   */
+  public static String windowsEscapeArg(String s) {
+    if (s.isEmpty()) {
+      return "\"\"";
+    } else {
+      boolean needsEscape = false;
+      for (int i = 0; i < s.length(); ++i) {
+        char c = s.charAt(i);
+        if (c == ' ' || c == '"') {
+          needsEscape = true;
+          break;
+        }
+      }
+      if (!needsEscape) {
+        return s;
+      }
+    }
+
+    StringBuilder result = new StringBuilder();
+    result.append('"');
+    int start = 0;
+    for (int i = 0; i < s.length(); ++i) {
+      char c = s.charAt(i);
+      if (c == '"' || c == '\\') {
+        // Copy the segment since the last special character.
+        if (start >= 0) {
+          result.append(s, start, i);
+          start = -1;
+        }
+
+        // Handle the current special character.
+        if (c == '"') {
+          // This is a quote character. Escape it with a single backslash.
+          result.append("\\\"");
+        } else {
+          // This is a backslash (or the first one in a run of backslashes).
+          // Whether we escape it depends on whether the run ends with a quote.
+          int runLen = 1;
+          int j = i + 1;
+          while (j < s.length() && s.charAt(j) == '\\') {
+            runLen++;
+            j++;
+          }
+          if (j == s.length()) {
+            // The run of backslashes goes to the end.
+            // We have to escape every backslash with another backslash.
+            for (int k = 0; k < runLen * 2; ++k) {
+              result.append('\\');
+            }
+            break;
+          } else if (j < s.length() && s.charAt(j) == '"') {
+            // The run of backslashes is terminated by a quote.
+            // We have to escape every backslash with another backslash, and
+            // escape the quote with one backslash.
+            for (int k = 0; k < runLen * 2; ++k) {
+              result.append('\\');
+            }
+            result.append("\\\"");
+            i += runLen; // 'i' is also increased in the loop iteration step
+          } else {
+            // No quote found. Each backslash counts for itself, they must not be
+            // escaped.
+            for (int k = 0; k < runLen; ++k) {
+              result.append('\\');
+            }
+            i += runLen - 1; // 'i' is also increased in the loop iteration step
+          }
+        }
+      } else {
+        // This is not a special character. Start the segment if necessary.
+        if (start < 0) {
+          start = i;
+        }
+      }
+    }
+    // Save final segment after the last special character.
+    if (start != -1) {
+      result.append(s, start, s.length());
+    }
+    result.append('"');
+    return result.toString();
+  }
 }

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/windows/jni/WindowsProcesses.java

@@ -216,13 +216,19 @@ public static int getpid() {
 
   private static native int nativeGetpid();
 
+  // TODO(laszlocsomor): Replace this method with ShellUtils.windowsEscapeArg in order to fix
+  // https://github.com/bazelbuild/bazel/issues/7122
   public static String quoteCommandLine(List<String> argv) {
     StringBuilder result = new StringBuilder();
     for (int iArg = 0; iArg < argv.size(); iArg++) {
       if (iArg != 0) {
         result.append(" ");
       }
       String arg = argv.get(iArg);
+      if (arg.isEmpty()) {
+        result.append("\"\"");
+        continue;
+      }
       boolean hasSpace = arg.contains(" ");
       if (!arg.contains("\"") && !arg.contains("\\") && !hasSpace) {
         // fast path. Just append the input string.

dataset/GitHub_Java/bazelbuild.bazel/src/test/java/com/google/devtools/build/lib/shell/ShellUtilsTest.java

@@ -119,7 +119,7 @@ private void assertTokenizeFails(String copts, String expectedError) {
       tokenize(new ArrayList<String>(), copts);
       fail();
     } catch (ShellUtils.TokenizationException e) {
-      assertThat(e).hasMessageThat().isEqualTo(expectedError);
+      assertThat(e).hasMessage(expectedError);
     }
   }