fix two-line shear, issue c406

diff --git a/bin/perltidy b/bin/perltidy
index 42b9f19511eed4c75d3ffaae57c7942591b1d10b..e32580257682177925e6780bec6a9a3b454e61b4 100755 (executable)
--- a/bin/perltidy
+++ b/bin/perltidy
@@ -4096,7 +4096,7 @@ and attempt to delete non-bare commas,
 
 we delete a comma which has become bare, which is not what is wanted. This
 happened because the change was based on the starting rather than the final
-line breaks.  Rerunning with B<--converge> added fixes things
+line breaks.  Running with B<--converge> gives the desired result:
 
         # perltidy -wtc=b -dtc --converge
         f(
@@ -4104,7 +4104,7 @@ line breaks.  Rerunning with B<--converge> added fixes things
             b => 2,
         );
 
-because changes are based on the line breaks after the first iteration.
+because comma changes are based on the line breaks after the first iteration.
 
 The additional computer time needed by the B<--converge> option to do another
 iteration or two will not be noticable except for files with many thousands of
@@ -4118,27 +4118,9 @@ normally be necessary.
 
 =item *
 
-Perltidy does not add a trailing comma to a list which appears to be near a
-B<stability limit>.  So if a comma is unexpectedly not added, this is probably
-the reason.
-
-This issue can be illustrated with the following example. The closing brace is
-at column 80, the default line length:
-
-    # perltidy -atc -dtc -wtc=b
-    $menuitem_paste->signal_connect( 'activate' => sub { create_paste_window() }
-    );
-
-Adding a trailing comma would cause the maximum line length to be exceeded.
-This in turn would cause a different break point to occur for which the comma
-is no longer bare. So it would get deleted on the next formatting pass,
-returning things to the starting state. This is is an unstable situation.
-
-The rules used to detect and avoid instability work well but are not precise,
-so in some cases where perltidy will not add a comma, it may be possible to add
-a stable trailing comma with editing. For example, if the above example were
-run with B<-l=81 -atc -wtc=b>, perltidy would still not add a trailing comma,
-even though it would be stable.
+Perltidy does not add a trailing comma in some B<edge cases> which appear to
+be near a stability limit.  So if a comma is unexpectedly not added, this is
+probably the reason.
 
 =item *
 

diff --git a/dev-bin/run_convergence_tests.pl.expect b/dev-bin/run_convergence_tests.pl.expect
index 5f1d02b7c4f52b11716ca978651ae428cb26dcf0..6ed49f26bc27e2986b2f99daf2a2a109f04d4043 100644 (file)
--- a/dev-bin/run_convergence_tests.pl.expect
+++ b/dev-bin/run_convergence_tests.pl.expect
@@ -2791,7 +2791,8 @@ $term =
    {    # Don't allow interruptions
       $SIG{$_} = 'IGNORE';
    }
-   ( open( CHECKPOINT, "> $aub_tmp"
+   ( open(
+      CHECKPOINT, "> $aub_tmp"
    ) )
      ||    # This is just temporary...
      &abort(
@@ -2802,7 +2803,8 @@ $term =
    {       # Don't allow interruptions
       $SIG{$_} = 'IGNORE';
    }
-   ( open( CHECKPOINT, "> $aub_tmp"
+   ( open(
+      CHECKPOINT, "> $aub_tmp"
    ) )
      ||    # This is just temporary...
      &abort(
@@ -3099,8 +3101,9 @@ foreach $port (
 ==> b1105 <==
 foreach $port (
     sort
-         ( @ARGV[ 1 .. $#ARGV ]
-         ) )
+         (
+        @ARGV[ 1 .. $#ARGV ] )
+     )
 __END__
 foreach $port (
     sort
@@ -8326,16 +8329,16 @@ use vars qw($VERSION @ISA
             @EXPORT_OK %EXPORT_TAGS);
 
 ==> b1489 <==
-    $menuitem_dict->signal_connect ( 'activate' => sub { create_dict_window () }
-    );
-    $menuitem_dict->signal_connect ( 'activate' => sub { create_dict_window () }
-    );
+    $menuitem_dict->signal_connect (
+        'activate' => sub { create_dict_window () } );
+    $menuitem_dict->signal_connect (
+        'activate' => sub { create_dict_window () } );
 
 ==> b1490 <==
-$e_str->bind ( '<return>' => sub {$e_hnr->tabfocus if $e_hnr->can ( 'tabfocus' );}
-);
-$e_str->bind ( '<return>' => sub {$e_hnr->tabfocus if $e_hnr->can ( 'tabfocus' );}
-);
+$e_str->bind (
+'<return>' => sub {$e_hnr->tabfocus if $e_hnr->can ( 'tabfocus' );} );
+$e_str->bind (
+'<return>' => sub {$e_hnr->tabfocus if $e_hnr->can ( 'tabfocus' );} );
 
 ==> b156 <==
 # State 1
@@ -11392,14 +11395,12 @@ foreach my $x (
      )->join() ;
 
      threads->create(
-          sub { lock($COUNT) ; $COUNT++ ; }
-     )->join() ;
+          sub { lock($COUNT) ; $COUNT++ ; } )->join() ;
 
 ==> b978 <==
      $ans = threads->create( sub {
           threads->create(
-               sub { $p->greeting  }
-          )->join ;
+               sub { $p->greeting  } )->join ;
      } )->join ;
 
      $ans = threads->create( sub {

diff --git a/lib/Perl/Tidy/Formatter.pm b/lib/Perl/Tidy/Formatter.pm
index 0a9946b6507dea61ef25d676f51eeeed5925bd44..3145d3dc77fdee1f96849312a770c48c6b014ed9 100644 (file)
--- a/lib/Perl/Tidy/Formatter.pm
+++ b/lib/Perl/Tidy/Formatter.pm
@@ -29343,6 +29343,36 @@ sub break_long_lines {
             # separated by this line
         }
 
+        # Fix two-line shear (c406)
+        my $i_next_nonblank = $inext_to_go[$i_lowest];
+        if ( $tokens_to_go[$i_next_nonblank] eq ')' ) {
+
+            # Example of a '2 line shear':
+
+            #   $wrapped->add_around_modifier(
+            #       sub { push @tracelog => 'around 1'; $_[0]->(); } );
+
+            # If we try formatting this with increasing line lengths, the
+            # break based on bond strengths is after the '(' until the closing
+            # paren is just beyond the line length limit. In that case, it can
+            # switch to being just before the ')'.  This is rare, and may be
+            # undesirable because it can cause unexpected formatting
+            # variations between similar code, and worse, instability with
+            # trailing commas.  So we check for that here and put the break
+            # back after the opening '(' if the ')' is not preceded by a ','.
+            # Issue c406.
+            my $i_prev    = iprev_to_go($i_next_nonblank);
+            my $i_opening = $mate_index_to_go[$i_next_nonblank];
+            if (   $types_to_go[$i_prev] ne ','
+                && defined($i_opening)
+                && $i_opening > $i_last_break )
+            {
+                # set a forced breakpoint to block recombination
+                $i_lowest = $i_opening;
+                $forced_breakpoint_to_go[$i_lowest] = 1;
+            }
+        }
+
         # guard against infinite loop (should never happen)
         if ( $i_lowest <= $i_last_break ) {
             DEVEL_MODE