Do not replace manually installed sip when installing PyQt-builder.

src/tasks/pyqt.cpp

@@ -171,7 +171,24 @@ namespace mob::tasks {
     void pyqt::build_and_install_from_source()
     {
         // use pip to install the pyqt builder
-        run_tool(pip(pip::install).package("PyQt-builder").version(builder_version()));
+        if (python::build_type() == config::debug) {
+            // PyQt-builder has sip as a dependency, so installing it directly will
+            // replace the sip we have installed manually, but the installed sip will
+            // not work (see comment in sip::build() for details)
+            //
+            // the workaround is to install the dependencies manually (only packaging),
+            // and then use a --no-dependencies install with pip
+            //
+            run_tool(pip(pip::install).package("packaging"));
+            run_tool(pip(pip::install)
+                         .package("PyQt-builder")
+                         .no_dependencies()
+                         .version(builder_version()));
+        }
+        else {
+            run_tool(
+                pip(pip::install).package("PyQt-builder").version(builder_version()));
+        }
 
         // patch for builder.py
         run_tool(patcher()

src/tools/python.cpp

@@ -49,7 +49,7 @@ namespace mob {
         execute_and_join(p);
     }
 
-    pip::pip(ops op) : basic_process_runner("pip"), op_(op) {}
+    pip::pip(ops op) : basic_process_runner("pip"), op_(op), no_deps_{false} {}
 
     pip& pip::package(const std::string& s)
     {
@@ -69,6 +69,12 @@ namespace mob {
         return *this;
     }
 
+    pip& pip::no_dependencies()
+    {
+        no_deps_ = true;
+        return *this;
+    }
+
     void pip::do_run()
     {
         switch (op_) {
@@ -141,11 +147,21 @@ namespace mob {
                      .arg("--no-warn-script-location")
                      .arg("--disable-pip-version-check");
 
-        if (!package_.empty())
-            p.arg(package_ + "==" + version_);
+        if (!package_.empty()) {
+            if (version_.empty()) {
+                p.arg(package_);
+            }
+            else {
+                p.arg(package_ + "==" + version_);
+            }
+        }
         else if (!file_.empty())
             p.arg(file_);
 
+        if (no_deps_) {
+            p.arg("--no-dependencies");
+        }
+
         p.env(this_env::get().set("PYTHONUTF8", "1"));
 
         execute_and_join(p);

src/tools/tools.h

@@ -703,6 +703,10 @@ namespace mob {
         pip& version(const std::string& s);
         pip& file(const fs::path& p);
 
+        // do not install dependencies for the package
+        //
+        pip& no_dependencies();
+
     protected:
         // runs pip
         //
@@ -717,6 +721,9 @@ namespace mob {
         std::string version_;
         fs::path file_;
 
+        // no depndencies
+        bool no_deps_;
+
         // runs `-m ensurepip`, then upgrades pip
         //
         void do_ensure();