IDE: package editor: add dependency: check for cycle

git-svn-id: trunk@34540 -

ide/lazarusidestrconsts.pas

@@ -3392,7 +3392,14 @@ resourcestring
   lisProjAddThePackageNameIsInvalidPlaseChooseAnExistingPackag = 'The package '
     +'name %s%s%s is invalid.%sPlase choose an existing package.';
   lisProjAddDependencyAlreadyExists = 'Dependency already exists';
+  lisUnableToAddTheDependencyBecauseThePackageHasAlread2 = 'Unable to add the '
+    +'dependency %s, because the package %s has already a dependency to %s';
   lisVersionMismatch = 'Version mismatch';
+  lisUnableToAddTheDependencyBecauseThePackageHasAlread = 'Unable to add the '
+    +'dependency %s, because the package %s has already a dependency %s';
+  lisCycleDetected = 'Cycle detected';
+  lisUnableToAddTheDependencyBecauseThisWouldCreateACyc = 'Unable to add the '
+    +'dependency %s, because this would create a cycle. Dependency %s';
   lisProjAddTheProjectHasAlreadyADependency = 'The project has already a '
     +'dependency for the package %s%s%s.';
   lisProjAddPackageNotFound = 'Package not found';

packager/addtopackagedlg.pas

@@ -422,7 +422,6 @@ begin
 
   RequiredPackage:=PackageGraph.FindPackageWithName(NewPkgName,nil);
   if RequiredPackage<>nil then begin
-
     // check if there is a dependency, that requires another version
     ConflictDependency:=PackageGraph.FindConflictRecursively(
       LazPackage.FirstRequiredDependency,RequiredPackage);
@@ -430,7 +429,22 @@ begin
       DebugLn(['CheckAddingDependency ',LazPackage.Name,' requiring ',RequiredPackage.IDAsString,' conflicts with ',ConflictDependency.AsString]);
       if not Quiet then
         IDEMessageDialog(lisVersionMismatch,
-          'Unable to add the dependency '+RequiredPackage.IDAsString+', because the package '+LazPackage.Name+' has already a dependency '+ConflictDependency.AsString,
+          Format(lisUnableToAddTheDependencyBecauseThePackageHasAlread, [
+            RequiredPackage.IDAsString, LazPackage.Name, ConflictDependency.
+            AsString]),
+          mtError,[mbCancel]);
+      exit(mrCancel);
+    end;
+
+    // check if there is a cycle
+    ConflictDependency:=PackageGraph.FindDependencyRecursively(
+      RequiredPackage.FirstRequiredDependency,LazPackage.Name);
+    if ConflictDependency<>nil then begin
+      DebugLn(['CheckAddingDependency ',LazPackage.Name,' requiring ',RequiredPackage.IDAsString,' conflicts with ',ConflictDependency.AsString]);
+      if not Quiet then
+        IDEMessageDialog(lisCycleDetected,
+          Format(lisUnableToAddTheDependencyBecauseThisWouldCreateACyc, [
+            RequiredPackage.IDAsString, ConflictDependency.AsString(true)]),
           mtError,[mbCancel]);
       exit(mrCancel);
     end;
@@ -444,7 +458,8 @@ begin
     DebugLn(['CheckAddingDependency ',LazPackage.Name,' requiring ',NewPkgName,', but is already provided by ',ProvidingAPackage.IDAsString]);
     if WarnIfAlreadyThere then
       IDEMessageDialog(lisProjAddDependencyAlreadyExists,
-        'Unable to add the dependency '+RequiredPackage.IDAsString+', because the package '+LazPackage.Name+' has already a dependency to '+ProvidingAPackage.Name,
+        Format(lisUnableToAddTheDependencyBecauseThePackageHasAlread2, [
+          RequiredPackage.IDAsString, LazPackage.Name, ProvidingAPackage.Name]),
         mtError,[mbCancel]);
     exit(mrIgnore);
   end;

packager/packagedefs.pas

@@ -293,7 +293,7 @@ type
     procedure ConsistencyCheck;
     function IsCompatible(Pkg: TLazPackageID): boolean;
     procedure MakeCompatible(const PkgName: string; const Version: TPkgVersion);
-    function AsString: string;
+    function AsString(WithOwner: boolean = false): string;
     function NextUsedByDependency: TPkgDependency;
     function PrevUsedByDependency: TPkgDependency;
     function NextRequiresDependency: TPkgDependency;
@@ -1955,13 +1955,19 @@ begin
   if MaxVersion.Compare(Version)<0 then MaxVersion.Assign(Version);
 end;
 
-function TPkgDependency.AsString: string;
+function TPkgDependency.AsString(WithOwner: boolean): string;
 begin
+  if Self=nil then
+    exit('(nil)');
   Result:=FPackageName;
   if pdfMinVersion in FFlags then
     Result:=Result+' (>='+MinVersion.AsString+')';
   if pdfMaxVersion in FFlags then
     Result:=Result+' (<='+MaxVersion.AsString+')';
+  if WithOwner then begin
+    if Owner is TLazPackage then
+      Result:=TLazPackage(Owner).Name+' uses '+Result;
+  end;
 end;
 
 function TPkgDependency.NextUsedByDependency: TPkgDependency;