support setting empty values (sanely) & removing support for

space-gapping: '-o option= value'

That is a very old feature (straight from 1998), but it is super
surprising if you try setting empty values and instead get error
messages or a non-empty value as the next parameter is treated as the
value – which could have been empty, so if for some reason you need a
compatible way of setting an empty value try: '-o option="" ""'.

I can only guess that the idea was to support '-o option value', but we
survived 17 years without it, we will do fine in the future I guess.

Similar is the case for '-t= testing' even through '-t testing' existed
before and the code even tried to detect mistakes like '-t= -b' … all
gone now.

Technically that is as its removing a feature replacing it with another
a major interface break. In practice I really hope for my and their
sanity that nobody was using this; but if for some reaon you do: Remove
the space and be done.

I found the patch and the bugreport actually only after the fact, but
its reassuring that others are puzzled by this as well and hence a
thanks is in perfect order here as the patch is practical identical
[expect that this one here adds tests and other bonus items].

Thanks: Daniel Hartwig for initial patch.
Closes: 693092

1 files changed, 5 insertions, 20 deletions

diff --git a/apt-pkg/contrib/cmndline.cc b/apt-pkg/contrib/cmndline.cc
index eb48d1d75..c8a6e2787 100644
--- a/apt-pkg/contrib/cmndline.cc
+++ b/apt-pkg/contrib/cmndline.cc
@@ -205,17 +205,11 @@ bool CommandLine::HandleOpt(int &I,int argc,const char *argv[],
 
    /* Determine the possible location of an option or 0 if their is
       no option */
-   if (Opt[1] == 0 || (Opt[1] == '=' && Opt[2] == 0))
+   if (Opt[1] == 0)
    {
       if (I + 1 < argc && argv[I+1][0] != '-')
 	 Argument = argv[I+1];
-      
-      // Equals was specified but we fell off the end!
-      if (Opt[1] == '=' && Argument == 0)
-	 return _error->Error(_("Option %s requires an argument."),argv[I]);
-      if (Opt[1] == '=')
-	 CertainArg = true;
-	 
+
       IncI = 1;
    }
    else
@@ -244,20 +238,11 @@ bool CommandLine::HandleOpt(int &I,int argc,const char *argv[],
       // Arbitrary item specification
       if ((A->Flags & ArbItem) == ArbItem)
       {
-	 const char *J = strchr(Argument, '=');
-	 if (J == NULL)
+	 const char * const J = strchr(Argument, '=');
+	 if (J == nullptr)
 	    return _error->Error(_("Option %s: Configuration item specification must have an =<val>."),argv[I]);
 
-	 // = is trailing
-	 if (J[1] == 0)
-	 {
-	    if (I+1 >= argc)
-	       return _error->Error(_("Option %s: Configuration item specification must have an =<val>."),argv[I]);
-	    Conf->Set(string(Argument,J-Argument),string(argv[I++ +1]));
-	 }
-	 else
-	    Conf->Set(string(Argument,J-Argument),string(J+1));
-	 
+	 Conf->Set(string(Argument,J-Argument), J+1);
 	 return true;
       }