Strip leading spaces from Java codegen doc comments. This is better for consistency, and prevents nonfunctional codegen diffs for editions transforms post-proto formatting.

PiperOrigin-RevId: 600874574

src/google/protobuf/compiler/java/doc_comment.cc

@@ -11,6 +11,10 @@
 
 #include "google/protobuf/compiler/java/doc_comment.h"
 
+#include <stddef.h>
+
+#include <algorithm>
+#include <cctype>
 #include <string>
 #include <vector>
 
@@ -142,14 +146,20 @@ static void WriteDocCommentBodyForLocation(io::Printer* printer,
       printer->Print(" * <pre>\n");
     }
 
-    for (int i = 0; i < lines.size(); i++) {
-      // Most lines should start with a space.  Watch out for lines that start
-      // with a /, since putting that right after the leading asterisk will
-      // close the comment.
-      if (!lines[i].empty() && lines[i][0] == '/') {
-        printer->Print(" * $line$\n", "line", lines[i]);
+    for (size_t i = 0; i < lines.size(); i++) {
+      // Lines should start with a single space and any extraneous leading
+      // spaces should be stripped. For lines starting with a /, the leading
+      // space will prevent putting it right after the leading asterick from
+      // closing the comment.
+      std::string line = lines[i];
+      line.erase(line.begin(),
+                 std::find_if(line.begin(), line.end(), [](unsigned char ch) {
+                   return !std::isspace(ch);
+                 }));
+      if (!line.empty()) {
+        printer->Print(" * $line$\n", "line", line);
       } else {
-        printer->Print(" *$line$\n", "line", lines[i]);
+        printer->Print(" *\n");
       }
     }