internal/core/adt: avoid loops in debug printing

Printing adt values can cause infinite loops with structure sharing enabled. This is especially the case for partially evaluated Vertices, if a shared Vertex is printed for which the structural cycle is not yet detected. We use the recently added cycle detection mechanism to whether a node is cyclic and/or shared in a Vertex. This is a rather conservative method and may mark false positives. This is okay as it serves the purpose of avoiding printing cycles only and is not otherwise involved in operations. We could enabled printing with structure sharing in more tests, but this would produce rather large diffs. We could still consider this later, especially once the old evaluator has been removed and the output from the new evaluator become the new golden files. Issue #2884 Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com> Change-Id: Icc5641446c8b5b9a4d4f67b584ccaa7114939890 Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1193845 TryBot-Result: CUEcueckoo <cueckoo@cuelang.org> Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com> Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
cue-lang · Apr 27, 2024 · bae8bbf · bae8bbf
1 parent 831374c
commit bae8bbf
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Showing 12 changed files with 319 additions and 295 deletions.
diff --git a/cue/testdata/benchmarks/listdisj.txtar b/cue/testdata/benchmarks/listdisj.txtar
@@ -64,26 +64,16 @@ Retain: 0
 Unifications: 15
 Conjuncts:    43
 Disjuncts:    4
--- out/eval --
+-- out/evalalpha --
 (struct){
   #T: (list){
     0: (string){ "d" }
   }
-  x: (list){
-    0: (string){ "d" }
-  }
-  y: (list){
-    0: (string){ "d" }
-  }
-  z: (list){
-    0: (string){ "d" }
-  }
-  v: (list){
-    0: (string){ "d" }
-  }
-  #X: (list){
-    0: (string){ "d" }
-  }
+  x: ~(#T)
+  y: ~(#T)
+  z: ~(#T)
+  v: ~(#T)
+  #X: ~(#T)
 }
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
@@ -106,6 +96,58 @@ diff old new
 +Unifications: 15
 +Conjuncts:    43
 +Disjuncts:    4
+-- diff/-out/evalalpha<==>+out/eval --
+diff old new
+--- old
++++ new
+@@ -2,19 +2,9 @@
+   #T: (list){
+     0: (string){ "d" }
+   }
+-  x: (list){
+-    0: (string){ "d" }
+-  }
+-  y: (list){
+-    0: (string){ "d" }
+-  }
+-  z: (list){
+-    0: (string){ "d" }
+-  }
+-  v: (list){
+-    0: (string){ "d" }
+-  }
+-  #X: (list){
+-    0: (string){ "d" }
+-  }
++  x: ~(#T)
++  y: ~(#T)
++  z: ~(#T)
++  v: ~(#T)
++  #X: ~(#T)
+ }
+-- out/eval --
+(struct){
+  #T: (list){
+    0: (string){ "d" }
+  }
+  x: (list){
+    0: (string){ "d" }
+  }
+  y: (list){
+    0: (string){ "d" }
+  }
+  z: (list){
+    0: (string){ "d" }
+  }
+  v: (list){
+    0: (string){ "d" }
+  }
+  #X: (list){
+    0: (string){ "d" }
+  }
+}
+-- diff/explanation --
+Differences fully due to rendered structure sharing.
 -- out/eval/stats --
 Leaks:  0
 Freed:  447

diff --git a/cue/testdata/cycle/constraints.txtar b/cue/testdata/cycle/constraints.txtar
@@ -664,15 +664,7 @@ Result:
     // [structural cycle]
     t1: (_|_){
       // [structural cycle]
-      a: (_|_){
-        // [structural cycle]
-        b: (_|_){
-          // [structural cycle]
-          b: (_|_){
-            // [structural cycle] selfTriggerCycle.t1.#T.b.b: structural cycle
-          }
-        }
-      }
+      a: ~(selfTriggerCycle.t1.#T)
       #T: (_|_){
         // [structural cycle]
         b: (_|_){
@@ -735,49 +727,16 @@ Result:
             link: (#struct){
               a: (#struct){
                 two: (#struct){
-                  link: (_|_){
-                    // [structural cycle]
-                    a: (_|_){
-                      // [structural cycle]
-                      b: (_|_){
-                        // [structural cycle]
-                        link: (_|_){
-                          // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-                        }
-                      }
-                    }
-                  }
+                  link: ~(selfTriggerCycle.issue1503.#T)
                 }
                 b: (#struct){
-                  link: (_|_){
-                    // [structural cycle]
-                    a: (_|_){
-                      // [structural cycle]
-                      b: (_|_){
-                        // [structural cycle]
-                        link: (_|_){
-                          // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-                        }
-                      }
-                    }
-                  }
+                  link: ~(selfTriggerCycle.issue1503.#T)
                 }
               }
             }
           }
           b: (#struct){
-            link: (_|_){
-              // [structural cycle]
-              a: (_|_){
-                // [structural cycle]
-                b: (_|_){
-                  // [structural cycle]
-                  link: (_|_){
-                    // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-                  }
-                }
-              }
-            }
+            link: ~(selfTriggerCycle.issue1503.#T)
           }
         }
       }
@@ -854,17 +813,21 @@ diff old new
          }
        }
      }
-@@ -222,6 +222,9 @@
+@@ -218,12 +218,7 @@
+     // [structural cycle]
+     t1: (_|_){
+       // [structural cycle]
+-      a: (_|_){
+-        // [structural cycle]
+-        b: (_|_){
+-          // [structural cycle]
+-        }
+-      }
++      a: ~(selfTriggerCycle.t1.#T)
+       #T: (_|_){
          // [structural cycle]
          b: (_|_){
-           // [structural cycle]
-+          b: (_|_){
-+            // [structural cycle] selfTriggerCycle.t1.#T.b.b: structural cycle
-+          }
-         }
-       }
-       #T: (_|_){
-@@ -280,22 +283,52 @@
+@@ -280,25 +275,22 @@
      }
      issue1503: (_|_){
        // [structural cycle]
@@ -884,55 +847,28 @@ diff old new
 -              // [structural cycle]
 -              a: (struct){
 -                two: (struct){
+-                }
+-              }
+-            }
 +      a: (#struct){
 +        a: (#struct){
 +          one: (#struct){
 +            link: (#struct){
 +              a: (#struct){
 +                two: (#struct){
-+                  link: (_|_){
-+                    // [structural cycle]
-+                    a: (_|_){
-+                      // [structural cycle]
-+                      b: (_|_){
-+                        // [structural cycle]
-+                        link: (_|_){
-+                          // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-+                        }
-+                      }
-+                    }
-+                  }
++                  link: ~(selfTriggerCycle.issue1503.#T)
 +                }
 +                b: (#struct){
-+                  link: (_|_){
-+                    // [structural cycle]
-+                    a: (_|_){
-+                      // [structural cycle]
-+                      b: (_|_){
-+                        // [structural cycle]
-+                        link: (_|_){
-+                          // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-+                        }
-+                      }
-+                    }
-+                  }
++                  link: ~(selfTriggerCycle.issue1503.#T)
 +                }
 +              }
 +            }
 +          }
 +          b: (#struct){
-+            link: (_|_){
-+              // [structural cycle]
-+              a: (_|_){
-+                // [structural cycle]
-+                b: (_|_){
-+                  // [structural cycle]
-+                  link: (_|_){
-+                    // [structural cycle] selfTriggerCycle.issue1503.#T.a.b.link: structural cycle
-+                  }
-                 }
-               }
-             }
++            link: ~(selfTriggerCycle.issue1503.#T)
+           }
+         }
+       }
 -- diff/todo/p2 --
 issue1503: cycle detected too late (but not super late)
 selfTriggerCycle.t1.a.b.b: cycle detected slightly too late