Better fix_includes handling of template lines

When multiple forward declarations were present of the form:

template<typename T>
class Foo;

fix_includes.py would consider the multiple 'template<typename T>'
lines to be duplicates and delete all but one.

Fix that, and add a test for it.

2 files changed, 77 insertions, 11 deletions

diff --git a/fix_includes.py b/fix_includes.py
index cf9e9e5..c696e3f 100755
--- a/fix_includes.py
+++ b/fix_includes.py
@@ -1124,6 +1124,8 @@ def _DeleteDuplicateLines(file_lines, line_ranges):
   particular, it should not cover lines that may have C literal
   strings in them.
 
+  We only delete whole move_spans, not lines within them.
+
   Arguments:
     file_lines: an array of LineInfo objects.
     line_ranges: a list of [start_line, end_line) pairs.
@@ -1131,13 +1133,21 @@ def _DeleteDuplicateLines(file_lines, line_ranges):
   seen_lines = set()
   for line_range in line_ranges:
     for line_number in range(*line_range):
-      if file_lines[line_number].type in (_BLANK_LINE_RE, _COMMENT_LINE_RE):
+      line_info = file_lines[line_number]
+      if line_info.type in (_BLANK_LINE_RE, _COMMENT_LINE_RE):
+        continue
+      if line_number != line_info.move_span[0]:
         continue
-      uncommented_line = _COMMENT_RE.sub('', file_lines[line_number].line)
-      if uncommented_line in seen_lines:
-        file_lines[line_number].deleted = True
-      elif not file_lines[line_number].deleted:
-        seen_lines.add(uncommented_line)
+      span_line_numbers = range(line_info.move_span[0], line_info.move_span[1])
+      line_infos_in_span = [file_lines[i] for i in span_line_numbers]
+      uncommented_lines = [
+          _COMMENT_RE.sub('', inf.line.strip()) for inf in line_infos_in_span]
+      uncommented_span = ' '.join(uncommented_lines)
+      if uncommented_span in seen_lines:
+        for info in line_infos_in_span:
+          info.deleted = True
+      elif not line_info.deleted:
+        seen_lines.add(uncommented_span)
 
 
 def _DeleteExtraneousBlankLines(file_lines, line_range):
diff --git a/fix_includes_test.py b/fix_includes_test.py
index 09ffb69..1592b7c 100755
--- a/fix_includes_test.py
+++ b/fix_includes_test.py
@@ -2810,7 +2810,7 @@ The full include-list for comments_with_includes:
     self.RegisterFileContents({'comments_with_includes': infile})
     self.ProcessAndTest(iwyu_output)
 
-  def testRemoveDuplicates(self):
+  def testRemoveDuplicateIncludes(self):
     """Tests we uniquify if an #include is in there twice."""
     infile = """\
 // Copyright 2010
@@ -2830,19 +2830,75 @@ The full include-list for comments_with_includes:
 int main() { return 0; }
 """
     iwyu_output = """\
-remove_duplicates should add these lines:
+remove_duplicate_includes should add these lines:
 #include <stdio.h>
 
-remove_duplicates should remove these lines:
+remove_duplicate_includes should remove these lines:
 - #include <notused.h>  // lines 3-3
 
-The full include-list for remove_duplicates:
+The full include-list for remove_duplicate_includes:
 #include <stdio.h>
 #include "used.h"
 #include "used2.h"
 ---
 """
-    self.RegisterFileContents({'remove_duplicates': infile})
+    self.RegisterFileContents({'remove_duplicate_includes': infile})
+    self.ProcessAndTest(iwyu_output)
+
+  def testRemoveDuplicateForwardDeclarations(self):
+    """Tests we uniquify if an #include is in there twice."""
+    infile = """\
+#include <notused.h>  ///-
+class A;
+template<typename T> // Comment in the middle not a problem
+class B;
+class A; ///-
+template<typename T> ///-
+class B; ///-
+template<typename T> class B; ///-
+
+int main() { return 0; }
+"""
+    iwyu_output = """\
+remove_duplicate_forward_declarations should add these lines:
+
+remove_duplicate_forward_declarations should remove these lines:
+- #include <notused.h>  // lines 1-1
+
+The full include-list for remove_duplicate_forward_declarations:
+class A;  // lines 2-2
+template <typename T> class B;  // lines 3-4
+class A;  // lines 5-5
+template <typename T> class B;  // lines 6-7
+template <typename T> class B;  // lines 8-8
+---
+"""
+    self.RegisterFileContents({'remove_duplicate_forward_declarations': infile})
+    self.ProcessAndTest(iwyu_output)
+
+  def testDontRemoveTemplateLines(self):
+    """Tests we don't accidentally think repeated template lines are dupes."""
+    infile = """\
+#include <notused.h>  ///-
+template<typename T>
+class A;
+template<typename T>
+class B;
+
+void f(A&, B&);
+"""
+    iwyu_output = """\
+dont_remove_template_lines should add these lines:
+
+dont_remove_template_lines should remove these lines:
+- #include <notused.h>  // lines 1-1
+
+The full include-list for dont_remove_template_lines:
+template <typename T> class A;  // lines 2-3
+template <typename T> class B;  // lines 4-5
+---
+"""
+    self.RegisterFileContents({'dont_remove_template_lines': infile})
     self.ProcessAndTest(iwyu_output)
 
   def testNestedNamespaces(self):