public Builder mergeSourceVersion(com.google.devtools.cloudtrace.v2.TruncatableString value) {
        if (sourceVersionBuilder_ == null) {
          if (((bitField0_ & 0x00000040) != 0)
              && sourceVersion_ != null
              && sourceVersion_
                  != com.google.devtools.cloudtrace.v2.TruncatableString.getDefaultInstance()) {
            getSourceVersionBuilder().mergeFrom(value);
          } else {
            sourceVersion_ = value;
          }
        } else {
          sourceVersionBuilder_.mergeFrom(value);
        }
        if (sourceVersion_ != null) {
          bitField0_ |= 0x00000040;
          onChanged();
        }
        return this;
      }
<pre>
The version of the deployed source code (up to 128 bytes).
</pre>

<code>.google.devtools.cloudtrace.v2.TruncatableString source_version = 7;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/StackTrace.java