Fix did-you-mean system

README.md

@@ -1,4 +1,4 @@
-# CLIforge
+# CLIForge
 
 A header-only C++20 engine for building CLIs whose commands are ordinary
 free functions. Parameters and options are explicitly typed where
@@ -158,6 +158,26 @@ three, clearly separated, rather than silently picking one. A
 fully-specified prefix (`project myapp delete --help`) narrows to the
 one actual match, exactly as before.
 
+The same treatment applies to an *incomplete* command that wasn't
+explicitly asking for help: `packctl project` alone is missing
+`<name>`, and that's equally true of all three `project` commands (they
+report the identical error). Rather than arbitrarily surfacing whichever
+one happened to be registered first, every command tied for "most
+specific incomplete match" is listed:
+
+```
+$ packctl project
+Error: missing required argument '<name>': expected a value of type string
+'project' matches 3 commands:
+  packctl project <name> create [OPTIONS]       Scaffold a new project from a template
+  packctl project <name> delete [OPTIONS]       Permanently delete a project by name
+  packctl project <name> [OPTIONS]              Show information about a project
+```
+
+A single most-specific match (e.g. `packctl project x create --template`,
+missing only `--template`'s value) still reports just the one relevant
+`Usage:` line, unchanged.
+
 ## Keeping allocations down
 
 * `TypeInfo`'s parser is a **plain stateless function pointer**, not

include/cliforge/engine.hpp

@@ -81,26 +81,47 @@ public:
         };
         std::vector<Candidate> candidates;
         std::string bestPartialError;
-        Command* bestPartialCmd = nullptr;
+        std::vector<Command*> bestPartialCmds;  // every command tied for the best partial score
         int bestPartialScore = -1;
         for (auto& cmd : commands_) {
             StructuredMatch m = cmd->tryMatchStructured(tokens);
             if (m.success) {
                 candidates.push_back({cmd.get(), std::move(m)});
-            } else if (!m.error.empty() && m.keywordScore > bestPartialScore) {
-                bestPartialScore = m.keywordScore;
-                bestPartialError = m.error;
-                bestPartialCmd = cmd.get();
+            } else if (!m.error.empty()) {
+                if (m.keywordScore > bestPartialScore) {
+                    bestPartialScore = m.keywordScore;
+                    bestPartialError = m.error;
+                    bestPartialCmds.clear();
+                    bestPartialCmds.push_back(cmd.get());
+                } else if (m.keywordScore == bestPartialScore) {
+                    // Genuinely tied -- e.g. "project" alone is an equally
+                    // incomplete prefix of create/delete/info, all of which
+                    // report the identical "missing <name>" error. Rather
+                    // than silently picking whichever was registered first
+                    // (which read as an arbitrary, misleading suggestion),
+                    // remember all of them and show every option.
+                    bestPartialCmds.push_back(cmd.get());
+                }
             }
         }
 
         if (candidates.empty()) {
-            if (bestPartialCmd) {
+            if (!bestPartialCmds.empty()) {
                 // Every keyword matched some command, just with a bad or
                 // missing argument value -- this is much more actionable
                 // than a generic "no command matches" + fuzzy suggestions.
                 std::cerr << "Error: " << bestPartialError << "\n";
-                std::cerr << "Usage: " << programName_ << " " << bestPartialCmd->usageLine() << "\n";
+                if (bestPartialCmds.size() == 1) {
+                    std::cerr << "Usage: " << programName_ << " " << bestPartialCmds.front()->usageLine()
+                               << "\n";
+                } else {
+                    std::cerr << "'" << join(tokens) << "' matches " << bestPartialCmds.size()
+                               << " commands:\n";
+                    for (auto* cmd : bestPartialCmds) {
+                        std::string line = programName_ + " " + cmd->usageLine();
+                        std::cerr << "  " << padRight(line, 46) << firstLine(cmd->description()) << "\n";
+                    }
+                }
                 return 1;
             }
             std::cerr << "Error: no command matches '" << join(tokens) << "'.\n";