clang-format: ignore not staged hunks

09:28 <@sberg> vmiklos, I think I ran into a scenario last night where I had
both `git add`-ed and non-added changes in a non-blacklisted file, and the
non-added changes violated clang-format (and the added ones did not), and the
commit hook complained

So make sure we validate the index version, not the filesystem one.

(And modify a formatted file to trigger CI validation of the hook change
itself.)

Change-Id: I6431b35ac50dd03741104b5709c5195d6ff28632
Reviewed-on: https://gerrit.libreoffice.org/46368Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>

.git-hooks/pre-commit

@@ -161,8 +161,7 @@ sub check_style($)
                 print("cp clang-format-$version-$platform clang-format\n");
                 print("chmod +x clang-format\n\n");
 
-                print("(Or read the instructions how to build it yourself at\n");
-                print("<https://dev-www.libreoffice.org/bin/README.clang-format.txt>).\n\n");
+                print("(Or read solenv/clang-format/README on how to build it yourself.\n");
                 return;
             }
             if (!ClangFormat::check_style($clang_format, $filename))

solenv/clang-format/ClangFormat.pm

@@ -91,11 +91,19 @@ sub find()
     return $clang_format;
 }
 
-# Diffs the original and the formatted version of a single file.
+# Diffs the original and the formatted version of a single file from the index.
 sub check_style($$)
 {
+    # Make sure that not staged changes are not considered when diffing.
     my ($clang_format, $filename) = @_;
-    return system("'$clang_format' $filename | git --no-pager diff --no-index --exit-code $filename -") == 0;
+    my $index = $filename . ".index";
+    system("git show :$filename > $index");
+    my $format = $index . ".format";
+    system("'$clang_format' -assume-filename=$filename $index > $format");
+    my $ret = system("git --no-pager diff --no-index --exit-code $index $format") == 0;
+    unlink($index);
+    unlink($format);
+    return $ret;
 }
 
 # Private functions.

writerfilter/source/rtftok/rtfdocumentimpl.cxx

@@ -3140,7 +3140,7 @@ RTFError RTFDocumentImpl::popState()
             {
                 if (m_aStates.top().eDestination == Destination::LISTOVERRIDEENTRY)
                 {
-                    // copy properties upwards so upper popState inserts it
+                    // copy properties upwards so upper popState() inserts it
                     m_aStates.top().aTableAttributes = aState.aTableAttributes;
                     m_aStates.top().aTableSprms = aState.aTableSprms;
                 }