.git-hook: Emit some warning about clang-format and renamed files

...to avoid misguided clang-format'ing of previously excluded files, as
discussed in the comment at
<https://gerrit.libreoffice.org/c/core/+/142387/4#message-ce27921261661fe7488ef0564657dbb5b42fb5fa>
"sc: factor out common code in make files".

(Though this still doesn't warn about cases where some excluded file got renamed
and the excludelist wasn't updated and the user already erroneously
clang-format'ed the renamed file before this commit attempt.   Also, I don't
know how best to integrate this with libreoffice.autostyle, so just ignore
libreoffice.autostyle for now when any suspicious renames are detected.)

Change-Id: I8d176ce536548b67f5b2af100f579f362764b06b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/142394
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 48 insertions, 5 deletions

diff --git a/.git-hooks/pre-commit b/.git-hooks/pre-commit
index a3cef10ee5f4..51c1de751672 100755
--- a/.git-hooks/pre-commit
+++ b/.git-hooks/pre-commit
@@ -184,6 +184,7 @@ sub check_style($)
     my ($h) = @_;
     my $src = ClangFormat::get_extension_regex();
     my @bad_names = ();
+    my @bad_renames = ();
     my $clang_format = ClangFormat::find();
 
     ## Check if ClangFormat has get_excludelist or the old
@@ -193,6 +194,17 @@ sub check_style($)
     if ($@) { $excluded_list_names = ClangFormat::get_blacklist(); }
     else    { $excluded_list_names = ClangFormat::get_excludelist(); }
 
+    # Get a list of renamed files.
+    my %renames; # key is target pathname, value is source pathname
+    open (IN, "git diff-index --cached --find-renames --diff-filter=R --name-status $h |")
+        || die "Cannot run git diff.";
+    while (my $line = <IN>)
+    {
+        chomp $line;
+        $line =~ /^[^\t]+\t([^\t]+)\t([^\t]+)$/ ||  die "Unexpected response line: $line";
+        $renames{$2} = $1;
+    }
+
     # Get a list of non-deleted changed files.
     open (FILES, "git diff-index --cached --diff-filter=AM --name-only $h |") ||  die "Cannot run git diff.";
     while (my $filename = <FILES>)
@@ -233,21 +245,52 @@ sub check_style($)
             }
             if (!ClangFormat::check_style($clang_format, $filename))
             {
-                push @bad_names, $filename;
+                if (defined($renames{$filename}))
+                {
+                    push @bad_renames, $filename;
+                }
+                else
+                {
+                    push @bad_names, $filename;
+                }
             }
         }
     }
 
     # Enforce style.
-    if (scalar @bad_names)
+    if (scalar @bad_names || scalar @bad_renames)
     {
         my $autostyle = `git config libreoffice.autostyle`;
         chomp $autostyle;
-        if ($autostyle ne "true")
+        if ($autostyle ne "true" or scalar @bad_renames)
         {
             print("\nThe above differences were found between the code to commit \n");
-            print("and the clang-format rules. You can apply these changes with:\n");
-            print("\n$clang_format -i " . join(" ", @bad_names) . "\n\n");
+            print("and the clang-format rules.\n");
+            if (scalar @bad_names)
+            {
+                print("You can apply these changes with:\n");
+                print("\n$clang_format -i " . join(" ", @bad_names) . "\n\n");
+            }
+            if (scalar @bad_renames)
+            {
+                print("\nATTENTION: Of files detected as renamed by git, the following ones are\n");
+                print("not clang-format'ed and are not listed in the excludelist. If they are\n");
+                print("renames of previously excluded files, they should be added to the\n");
+                print("excludelist:\n\n");
+                foreach my $name (@bad_renames)
+                {
+                    if (exists($excluded_list_names->{$renames{$name}}))
+                    {
+                        print("* $name got renamed from $renames{$name},\n");
+                        print("    which is even still listed in the excludelist!\n");
+                    }
+                    else
+                    {
+                        print("* $name\n");
+                    }
+                }
+                print("\n");
+            }
             print("Aborting commit. Apply changes and commit again or skip checking\n");
             print("with --no-verify (not recommended).\n");
             exit(1);