Merge branch 'jc/maint-blame-unique-abbrev' into maint

"git blame" did not try to make sure that the abbreviated commit
object names in its output are unique.

* jc/maint-blame-unique-abbrev:
  blame: compute abbreviation width that ensures uniqueness

diff --cc builtin/blame.c
index 24d3dd52920542b993d4945ccb2642a74da5f759,f13ec327f6707ec832214ff4ffca7d630048ca94..960c58d855a6f1a04ad1d08637fc75c3da240a30
--- 1/builtin/blame.c
--- 2/builtin/blame.c
+++ b/builtin/blame.c
@@@ -1837,6 -1828,28 +1837,16 @@@ static int read_ancestry(const char *gr
        return 0;
  }
  
 -/*
 - * How many columns do we need to show line numbers in decimal?
 - */
 -static int lineno_width(int lines)
 -{
 -      int i, width;
 -
 -      for (width = 1, i = 10; i <= lines; width++)
 -              i *= 10;
 -      return width;
 -}
 -
+ static int update_auto_abbrev(int auto_abbrev, struct origin *suspect)
+ {
+       const char *uniq = find_unique_abbrev(suspect->commit->object.sha1,
+                                             auto_abbrev);
+       int len = strlen(uniq);
+       if (auto_abbrev < len)
+               return len;
+       return auto_abbrev;
+ }
+ 
  /*
   * How many columns do we need to show line numbers, authors,
   * and filenames?
@@@ -1877,9 -1894,13 +1891,13 @@@ static void find_alignment(struct score
                if (largest_score < ent_score(sb, e))
                        largest_score = ent_score(sb, e);
        }
 -      max_orig_digits = lineno_width(longest_src_lines);
 -      max_digits = lineno_width(longest_dst_lines);
 -      max_score_digits = lineno_width(largest_score);
 +      max_orig_digits = decimal_width(longest_src_lines);
 +      max_digits = decimal_width(longest_dst_lines);
 +      max_score_digits = decimal_width(largest_score);
+ 
+       if (compute_auto_abbrev)
+               /* one more abbrev length is needed for the boundary commit */
+               abbrev = auto_abbrev + 1;
  }
  
  /*