Initialize plugins after handling initial command line flags

This is technically a breaking change, since attempting to set plugin
files after the first non-flag argument will now throw an error. This
is acceptable given the relative lack of stability in a plugin
interface and the need to tie the knot somewhere once plugins can
actually define new subcommands.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index 9377fe4c0..eb11fd64b 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -60,6 +60,7 @@ void Args::parseCmdline(const Strings & _cmdline)
         verbosity = lvlError;
     }
 
+    bool argsSeen = false;
     for (auto pos = cmdline.begin(); pos != cmdline.end(); ) {
 
         auto arg = *pos;
@@ -88,6 +89,10 @@ void Args::parseCmdline(const Strings & _cmdline)
                 throw UsageError("unrecognised flag '%1%'", arg);
         }
         else {
+            if (!argsSeen) {
+                argsSeen = true;
+                initialFlagsProcessed();
+            }
             pos = rewriteArgs(cmdline, pos);
             pendingArgs.push_back(*pos++);
             if (processArgs(pendingArgs, false))
@@ -96,6 +101,9 @@ void Args::parseCmdline(const Strings & _cmdline)
     }
 
     processArgs(pendingArgs, true);
+
+    if (!argsSeen)
+        initialFlagsProcessed();
 }
 
 bool Args::processFlag(Strings::iterator & pos, Strings::iterator end)
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 88f068087..4721c21df 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -132,6 +132,10 @@ protected:
 
     std::set<std::string> hiddenCategories;
 
+    /* Called after all command line flags before the first non-flag
+       argument (if any) have been processed. */
+    virtual void initialFlagsProcessed() {}
+
 public:
 
     void addFlag(Flag && flag);