better diagnostics on read operations from write-only

filehandles

p4raw-id: //depot/perl@3632

2 files changed, 24 insertions, 9 deletions

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 3284cf70da..be5366d116 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -229,6 +229,13 @@ was attempted.  This mostly eliminates confusing
 buffering mishaps suffered by users unaware of how Perl internally
 handles I/O.
 
+=head2 Better diagnostics on meaningless filehandle operations
+
+Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)>
+are compile time errors.  Attempting to read from filehandles that
+were opened only for writing will now produce warnings (just as
+writing to read-only filehandles does).
+
 =head1 Supported Platforms
 
 =over 4
@@ -467,16 +474,24 @@ A tutorial on managing class data for object modules.
 by Perl.  This combination appears in an interpolated variable or a
 C<'>-delimited regular expression.
 
-=item Unrecognized escape \\%c passed through
+=item Filehandle %s opened only for output
 
-(W) You used a backslash-character combination which is not recognized
-by Perl.
+(W) You tried to read from a filehandle opened only for writing.  If you
+intended it to be a read-write filehandle, you needed to open it with
+"+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing.  If
+you intended only to read from the file, use "E<lt>".  See
+L<perlfunc/open>.
 
 =item Missing command in piped open
 
 (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
 construction, but the command was missing or blank.
 
+=item Unrecognized escape \\%c passed through
+
+(W) You used a backslash-character combination which is not recognized
+by Perl.
+
 =item defined(@array) is deprecated
 
 (D) defined() is not usually useful on arrays because it checks for an
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index d7b9024998..45c7be1905 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -1265,7 +1265,7 @@ PDP-11 or something?
 You need to do an open() or a socket() call, or call a constructor from
 the FileHandle package.
 
-=item Filehandle %s opened for only input
+=item Filehandle %s opened only for input
 
 (W) You tried to write on a read-only filehandle.  If you
 intended it to be a read-write filehandle, you needed to open it with
@@ -1273,12 +1273,12 @@ intended it to be a read-write filehandle, you needed to open it with
 you intended only to write the file, use "E<gt>" or "E<gt>E<gt>".  See
 L<perlfunc/open>.
 
-=item Filehandle opened for only input
+=item Filehandle %s opened only for output
 
-(W) You tried to write on a read-only filehandle.  If you
+(W) You tried to read from a filehandle opened only for writing.  If you
 intended it to be a read-write filehandle, you needed to open it with
 "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing.  If
-you intended only to write the file, use "E<gt>" or "E<gt>E<gt>".  See
+you intended only to read from the file, use "E<lt>".  See
 L<perlfunc/open>.
 
 =item Final $ should be \$ or $name
@@ -2274,7 +2274,7 @@ are outside the range which can be represented by integers internally.
 One possible workaround is to force Perl to use magical string
 increment by prepending "0" to your numbers.
 
-=item Read on closed filehandle E<lt>%sE<gt>
+=item Read on closed filehandle %s
 
 (W) The filehandle you're reading from got itself closed sometime before now.
 Check your logic flow.
@@ -3169,7 +3169,7 @@ but in actual fact, you got
 
 So put in parentheses to say what you really mean.
 
-=item Write on closed filehandle
+=item Write on closed filehandle %s
 
 (W) The filehandle you're writing to got itself closed sometime before now.
 Check your logic flow.