Ruby: Fix bad join in controllerTemplateFile

Before
```
Evaluated relational algebra for predicate ActionController#32b59475::controllerTemplateFile#2#ff@6f4b2395 with tuple counts:
        31304524   ~0%    {2} r1 = JOIN locations_default_10#join_rhs WITH FileSystem#df18ed9a::Make#FileSystem#e91ad87f::Input#::Container::getRelativePath#0#dispred#ff ON FIRST 1 OUTPUT Lhs.1, Rhs.1
           34453   ~3%    {2} r2 = JOIN r1 WITH DataFlowPublic#e1781e31::ModuleNode::getLocation#0#dispred#ff_10#join_rhs ON FIRST 1 OUTPUT Rhs.1, Lhs.1

            1236   ~0%    {2} r3 = JOIN r2 WITH ActionController#32b59475::ActionControllerClass#f ON FIRST 1 OUTPUT Lhs.0, InverseAppend(("" ++ "app/controllers/"),"_controller.rb",Lhs.1)

            1236   ~1%    {2} r4 = SCAN r3 OUTPUT In.0, ("" ++ "app/views/layouts/" ++ In.1 ++ "%")

            1320   ~1%    {3} r5 = JOIN r2 WITH ActionController#32b59475::ActionControllerClass#f ON FIRST 1 OUTPUT Lhs.1, Lhs.0, "^(.*/)app/controllers/(?:.*?)/(?:[^/]*)$"
              14   ~7%    {5} r6 = JOIN r5 WITH PRIMITIVE regexpCapture#bbff ON Lhs.0,Lhs.2
              14   ~7%    {5} r7 = SELECT r6 ON In.3 = 1
              14   ~0%    {3} r8 = SCAN r7 OUTPUT In.1, In.4, InverseAppend((In.4 ++ "app/controllers/"),"_controller.rb",In.0)

              14   ~0%    {2} r9 = SCAN r8 OUTPUT In.0, (In.1 ++ "app/views/layouts/" ++ In.2 ++ "%")

            1250   ~1%    {2} r10 = r4 UNION r9
         8813750   ~2%    {3} r11 = JOIN r10 WITH Erb#b2b9e6ed::ErbFile#ff CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0, Lhs.1
         8813750   ~6%    {4} r12 = JOIN r11 WITH FileSystem#df18ed9a::Make#FileSystem#e91ad87f::Input#::Container::getRelativePath#0#dispred#ff ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.0, Rhs.1
              41   ~6%    {4} r13 = SELECT r12 ON In.3 matches In.1
              41   ~0%    {2} r14 = SCAN r13 OUTPUT In.0, In.2

            1236   ~0%    {2} r15 = SCAN r3 OUTPUT ("" ++ "app/views/" ++ In.1), In.0

              14   ~0%    {2} r16 = SCAN r8 OUTPUT (In.1 ++ "app/views/" ++ In.2), In.0

            1250   ~0%    {2} r17 = r15 UNION r16
             581   ~0%    {2} r18 = JOIN r17 WITH FileSystem#df18ed9a::Make#FileSystem#e91ad87f::Input#::Container::getRelativePath#0#dispred#ff_10#join_rhs ON FIRST 1 OUTPUT Rhs.1, Lhs.1
            3243   ~2%    {2} r19 = JOIN r18 WITH containerparent ON FIRST 1 OUTPUT Rhs.1, Lhs.1
            2767   ~0%    {2} r20 = JOIN r19 WITH Erb#b2b9e6ed::ErbFile#ff ON FIRST 1 OUTPUT Lhs.1, Lhs.0

            2808   ~0%    {2} r21 = r14 UNION r20
                          return r21
```

After
```
Evaluated relational algebra for predicate ActionController#32b59475::controllerTemplateFile#2#ff@4b56c4f9 with tuple counts:
          1236   ~0%    {2} r1 = SCAN ActionController#32b59475::getActionControllerClassRelativePath#1#ff OUTPUT In.0, InverseAppend(("" ++ "app/controllers/"),"_controller.rb",In.1)

          1236   ~0%    {2} r2 = SCAN r1 OUTPUT ("" ++ "app/views/" ++ In.1), In.0

          1320   ~0%    {3} r3 = SCAN ActionController#32b59475::getActionControllerClassRelativePath#1#ff OUTPUT In.0, In.1, "^(.*/)app/controllers/(?:.*?)/(?:[^/]*)$"
            14   ~0%    {5} r4 = JOIN r3 WITH PRIMITIVE regexpCapture#bbff ON Lhs.1,Lhs.2
            14   ~0%    {5} r5 = SELECT r4 ON In.3 = 1
            14   ~0%    {3} r6 = SCAN r5 OUTPUT In.0, In.4, InverseAppend((In.4 ++ "app/controllers/"),"_controller.rb",In.1)

            14   ~0%    {2} r7 = SCAN r6 OUTPUT (In.1 ++ "app/views/" ++ In.2), In.0

          1250   ~0%    {2} r8 = r2 UNION r7
           581   ~0%    {2} r9 = JOIN r8 WITH FileSystem#df18ed9a::Make#FileSystem#e91ad87f::Input#::Container::getRelativePath#0#dispred#ff_10#join_rhs ON FIRST 1 OUTPUT Rhs.1, Lhs.1
          3243   ~0%    {2} r10 = JOIN r9 WITH containerparent ON FIRST 1 OUTPUT Rhs.1, Lhs.1
          2767   ~0%    {2} r11 = JOIN r10 WITH Erb#b2b9e6ed::ErbFile#ff ON FIRST 1 OUTPUT Lhs.1, Lhs.0

          1236   ~1%    {3} r12 = SCAN r1 OUTPUT In.0, "", In.1

          1250   ~1%    {3} r13 = r12 UNION r6
        102500   ~0%    {4} r14 = JOIN r13 WITH project#ActionController#32b59475::getErbFileRelativePath#1#ff CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0, Lhs.1, Lhs.2
        102500   ~0%    {5} r15 = JOIN r14 WITH ActionController#32b59475::getErbFileRelativePath#1#ff_10#join_rhs ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.0
        102500   ~0%    {4} r16 = JOIN r15 WITH Erb#b2b9e6ed::ErbFile#ff ON FIRST 1 OUTPUT Lhs.1, Lhs.4, Lhs.0, (Lhs.2 ++ "app/views/layouts/" ++ Lhs.3 ++ "%")
            41   ~0%    {4} r17 = SELECT r16 ON In.1 matches In.3
            41   ~3%    {2} r18 = SCAN r17 OUTPUT In.0, In.2

          2808   ~1%    {2} r19 = r11 UNION r18
                        return r19
```

Author: hvitved

ruby/ql/lib/codeql/ruby/frameworks/ActionController.qll

@@ -511,6 +511,23 @@ ActionControllerClass getAssociatedControllerClass(ErbFile f) {
   )
 }
 
+pragma[nomagic]
+private string getActionControllerClassRelativePath(ActionControllerClass cls) {
+  result = cls.getLocation().getFile().getRelativePath()
+}
+
+pragma[nomagic]
+private string getErbFileRelativePath(ErbFile templateFile) {
+  result = templateFile.getRelativePath() and
+  result.matches("%app/views/layouts/%")
+}
+
+bindingset[result]
+pragma[inline_late]
+private string getErbFileRelativePathInlineLate(ErbFile templateFile) {
+  result = getErbFileRelativePath(templateFile)
+}
+
 // TODO: improve layout support, e.g. for `layout` method
 // https://guides.rubyonrails.org/layouts_and_rendering.html
 /**
@@ -522,15 +539,18 @@ ActionControllerClass getAssociatedControllerClass(ErbFile f) {
  */
 predicate controllerTemplateFile(ActionControllerClass cls, ErbFile templateFile) {
   exists(string sourcePrefix, string subPath, string controllerPath |
-    controllerPath = cls.getLocation().getFile().getRelativePath() and
+    controllerPath = getActionControllerClassRelativePath(cls) and
     // `sourcePrefix` is either a prefix path ending in a slash, or empty if
     // the rails app is at the source root
     sourcePrefix = [controllerPath.regexpCapture("^(.*/)app/controllers/(?:.*?)/(?:[^/]*)$", 1), ""] and
-    controllerPath = sourcePrefix + "app/controllers/" + subPath + "_controller.rb" and
-    (
-      sourcePrefix + "app/views/" + subPath = templateFile.getParentContainer().getRelativePath()
-      or
-      templateFile.getRelativePath().matches(sourcePrefix + "app/views/layouts/" + subPath + "%")
+    controllerPath = sourcePrefix + "app/controllers/" + subPath + "_controller.rb"
+  |
+    sourcePrefix + "app/views/" + subPath = templateFile.getParentContainer().getRelativePath()
+    or
+    exists(string path |
+      path = getErbFileRelativePath(_) and
+      path.matches(sourcePrefix + "app/views/layouts/" + subPath + "%") and
+      path = getErbFileRelativePathInlineLate(templateFile)
     )
   )
 }