Warn users that Requests doesn't support HTTP/2 (#361)

fixtures/curl_commands/get_http2_warning.sh

@@ -0,0 +1 @@
+curl --http2 example.com

fixtures/python/get_http2_warning.py

@@ -0,0 +1,4 @@
+import requests
+
+# Warning: this was an HTTP/2 request but requests only supports HTTP/1.1
+response = requests.get('http://example.com')

generators/python.js

@@ -448,6 +448,12 @@ export const _toPython = request => {
   } else if (filesString) {
     pythonCode += filesString + '\n'
   }
+
+  if (request.http2 || request.http3) {
+    // TODO: warn users out of band, not in the generated code
+    const version = request.http2 ? '2' : '3'
+    pythonCode += `# Warning: this was an HTTP/${version} request but requests only supports HTTP/1.1\n`
+  }
   pythonCode += requestLine
 
   if (jsonDataString && !jsonDataStringRoundtrips) {

util.js

@@ -1159,6 +1159,13 @@ const buildRequest = parsedArguments => {
     request.output = parsedArguments.output
   }
 
+  if (parsedArguments.http2) {
+    request.http2 = parsedArguments.http2
+  }
+  if (parsedArguments.http3) {
+    request.http3 = parsedArguments.http3
+  }
+
   return request
 }