stdlib: Make pP insert no line breaks with field width zero

See also https://bugs.erlang.org/browse/ERL-607.

A zero field width used to insert line breaks "everywhere", but with
this patch no line breaks are inserted.

1 files changed, 20 insertions, 2 deletions

diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl
index 13f2cbd27b..91fe1133f6 100644
--- a/lib/stdlib/test/io_SUITE.erl
+++ b/lib/stdlib/test/io_SUITE.erl
@@ -31,7 +31,7 @@
          otp_10836/1, io_lib_width_too_small/1,
          io_with_huge_message_queue/1, format_string/1,
 	 maps/1, coverage/1, otp_14178_unicode_atoms/1, otp_14175/1,
-         otp_14285/1, limit_term/1, otp_14983/1]).
+         otp_14285/1, limit_term/1, otp_14983/1, otp_15103/1]).
 
 -export([pretty/2, trf/3]).
 
@@ -63,7 +63,7 @@ all() ->
      io_lib_print_binary_depth_one, otp_10302, otp_10755, otp_10836,
      io_lib_width_too_small, io_with_huge_message_queue,
      format_string, maps, coverage, otp_14178_unicode_atoms, otp_14175,
-     otp_14285, limit_term, otp_14983].
+     otp_14285, limit_term, otp_14983, otp_15103].
 
 %% Error cases for output.
 error_1(Config) when is_list(Config) ->
@@ -2615,3 +2615,21 @@ trf(Format, Args, T) ->
 
 trf(Format, Args, T, Opts) ->
     lists:flatten(io_lib:format(Format, Args, [{chars_limit, T}|Opts])).
+
+otp_15103(_Config) ->
+    T = lists:duplicate(5, {a,b,c}),
+
+    S1 = io_lib:format("~0p", [T]),
+    "[{a,b,c},{a,b,c},{a,b,c},{a,b,c},{a,b,c}]" = lists:flatten(S1),
+    S2 = io_lib:format("~-0p", [T]),
+    "[{a,b,c},{a,b,c},{a,b,c},{a,b,c},{a,b,c}]" = lists:flatten(S2),
+    S3 = io_lib:format("~1p", [T]),
+    "[{a,\n  b,\n  c},\n {a,\n  b,\n  c},\n {a,\n  b,\n  c},\n {a,\n  b,\n"
+    "  c},\n {a,\n  b,\n  c}]" = lists:flatten(S3),
+
+    S4 = io_lib:format("~0P", [T, 5]),
+    "[{a,b,c},{a,b,...},{a,...},{...}|...]" = lists:flatten(S4),
+    S5 = io_lib:format("~1P", [T, 5]),
+    "[{a,\n  b,\n  c},\n {a,\n  b,...},\n {a,...},\n {...}|...]" =
+        lists:flatten(S5),
+    ok.