cpp, qt: Use uidhash to select uids for signing

* lang/cpp/src/gpgsignkeyeditinteractor.cpp (action):
Use uidhash instead of number.
(GpgSignKeyEditInteractor::setKey): New.
* lang/cpp/src/gpgsignkeyeditinteractor.h: Update accordingly.
* lang/cpp/src/key.h, lang/cpp/src/key.cpp: Wrap uidhash.
* lang/qt/src/qgpgmesignkeyjob.cpp: Set the key.

--
Using the uidhash avoids problems when the user ids
on --edit-key are different ones then the uids
captured by gpgme when listing keys. Or if
they are in a different order. This can happen
with cached keys or keys with user attributes.

lang/cpp/src/gpgsignkeyeditinteractor.cpp

@@ -65,6 +65,7 @@ public:
     std::vector<unsigned int>::const_iterator currentId, nextId;
     unsigned int checkLevel;
     bool dupeOk;
+    Key key;
 
     const char *command() const
     {
@@ -259,7 +260,17 @@ const char *GpgSignKeyEditInteractor::action(Error &err) const
     default:
         if (st >= UIDS_LIST_SEPARATELY && st < UIDS_LIST_SEPARATELY_DONE) {
             std::stringstream ss;
-            ss << d->nextUserID();
+            auto nextID = d->nextUserID();
+            const char *hash;
+            assert (nextID);
+            if (!d->key.isNull() && (hash = d->key.userID(nextID - 1).uidhash())) {
+                /* Prefer uidhash if it is available as it might happen
+                 * that uidattrs break the ordering of the uids in the
+                 * edit-key interface */
+                ss << "uid " << hash;
+            } else {
+                ss << nextID;
+            }
             d->scratch = ss.str();
             return d->scratch.c_str();
         }
@@ -318,6 +329,10 @@ unsigned int GpgSignKeyEditInteractor::nextState(unsigned int status, const char
     err = GENERAL_ERROR;
     return ERROR;
 }
+void GpgSignKeyEditInteractor::setKey(const Key &key)
+{
+    d->key = key;
+}
 
 void GpgSignKeyEditInteractor::setCheckLevel(unsigned int checkLevel)
 {

lang/cpp/src/gpgsignkeyeditinteractor.h

@@ -50,6 +50,7 @@ public:
 
     void setCheckLevel(unsigned int checkLevel);
     void setUserIDsToSign(const std::vector<unsigned int> &userIDsToSign);
+    void setKey(const Key &key);
     void setSigningOptions(int options);
 
     /* Set this if it is ok to overwrite an existing signature. In that

lang/cpp/src/key.cpp

@@ -673,6 +673,11 @@ const char *UserID::comment() const
     return uid ? uid->comment : nullptr ;
 }
 
+const char *UserID::uidhash() const
+{
+    return uid ? uid->uidhash : nullptr ;
+}
+
 UserID::Validity UserID::validity() const
 {
     if (!uid) {

lang/cpp/src/key.h

@@ -363,6 +363,7 @@ public:
     const char *name() const;
     const char *email() const;
     const char *comment() const;
+    const char *uidhash() const;
 
     enum Validity { Unknown = 0, Undefined = 1, Never = 2,
                     Marginal = 3, Full = 4, Ultimate = 5

lang/qt/src/qgpgmesignkeyjob.cpp

@@ -76,6 +76,7 @@ static QGpgMESignKeyJob::result_type sign_key(Context *ctx, const Key &key, cons
     skei->setUserIDsToSign(uids);
     skei->setCheckLevel(checkLevel);
     skei->setSigningOptions(opts);
+    skei->setKey(key);
 
     if (dupeOk) {
         ctx->setFlag("extended-edit", "1");