[clang-format] De-duplicate includes with leading or trailing whitespace.

[curdeius]

Summary

This fixes PR46555 (https://bugs.llvm.org/show_bug.cgi?id=46555).

[curdeius]

• Ooops. Revert unwanted test changes.

[curdeius]

Finally I've opted for creating a small revision just fixing this particular bug report.
Mind however that the problem is a bit more complex and to solve all possible cases we would need to first reformat the source code, then sort the includes and then again, possibly reformat parts of the source code modified by sorting, so that the comments get re-aligned etc.

[MyDeveloperDay]

This LGTM, generally I think clang-format seems to remove trailing spaces anyway so it might be that the duplicate might disappear on the second format. but I'm good with this approach

But as a side note I keep wondering who are these people who clang-format once and expect it to be perfect!

Firstly I'm clang-format -n checking my 4-5 million lines of code every night, secondly the CI system is checking, and thirdly in our company we using clang-format on save, and Ctrl-S and :w are like a tick for me.

By the time I check my code in I've clang-formatted it 100's of times. I don't even need to use git clang-format I know its perfect already!

This is in my view the resolution to pretty much all those, I have to do it twice! bugs..its a non issue for anyone with a zero tolerance policy to un-clang-formtted code!

[curdeius]

Thanks for the review.
I agree with you that a clang-format user should not expect a perfectly formatted code after a single iteration.
Maybe it's actually a documentation issue and we should be clear about it? Just a guarantee of 1) stability of formatting and 2) asymptotically arriving at the fully formatted code.
I'll think about how to word it and create a revision for the documentation (unless you judge it unnecessary).

BTW, I would be almost inclined to abandon this review and mark the bug report as invalid... but the change is so trivial...

clang/lib/Format/Format.cpp

static void sortCppIncludes(const FormatStyle &Style,
   unsigned CursorToEOLOffset;
   if (Cursor)
     std::tie(CursorIndex, CursorToEOLOffset) =
         FindCursorIndex(Includes, Indices, *Cursor);
 
   // Deduplicate #includes.
   Indices.erase(std::unique(Indices.begin(), Indices.end(),
                             [&](unsigned LHSI, unsigned RHSI) {
-                              return Includes[LHSI].Text == Includes[RHSI].Text;
+                              return Includes[LHSI].Text.trim() ==
+                                     Includes[RHSI].Text.trim();
                             }),
                 Indices.end());
 
   int CurrentCategory = Includes.front().Category;
 
   // If the #includes are out of order, we generate a single replacement fixing
   // the entire block. Otherwise, no replacement is generated.
   // In case Style.IncldueStyle.IncludeBlocks != IBS_Preserve, this check is not

clang/unittests/Format/SortIncludesTest.cpp

EXPECT_EQ("#include \"a.h\"\n"
                  "  #include \"c.h\"\n"
                  "   #include \"b.h\"\n"));
   EXPECT_EQ("#include \"a.h\"\n"
             "#include \"b.h\"\n"
             "#include \"c.h\"\n",
             sort("# include \"a.h\"\n"
                  "#  include \"c.h\"\n"
                  "#   include \"b.h\"\n"));
+  EXPECT_EQ("#include \"a.h\"\n", sort("#include \"a.h\"\n"
+                                       " #include \"a.h\"\n"));
+}
+
+TEST_F(SortIncludesTest, TrailingWhitespace) {
+  EXPECT_EQ("#include \"a.h\"\n"
+            "#include \"b.h\"\n"
+            "#include \"c.h\"\n",
+            sort("#include \"a.h\" \n"
+                 "#include \"c.h\"  \n"
+                 "#include \"b.h\"   \n"));
+  EXPECT_EQ("#include \"a.h\"\n", sort("#include \"a.h\"\n"
+                                       "#include \"a.h\" \n"));
 }
 
 TEST_F(SortIncludesTest, GreaterInComment) {
   EXPECT_EQ("#include \"a.h\"\n"
             "#include \"b.h\" // >\n"
             "#include \"c.h\"\n",
             sort("#include \"a.h\"\n"
                  "#include \"c.h\"\n"