internal/core/adt: allow sharing of lets

In cuelang.org/cl/1211742 we disabled sharing
for non-rooted values. This fixed some bugs related
to this. Unfortunately, it also exposed some bugs
with let values that otherwise were not exposed
with sharing enabled.

We partially enable sharing again to allow unblocking
some users. This may not be the most ideal
implementation, but at least it solves some issues
immediately.

One result was that the debug printer would print
shared let values of "multi-lets". This meant the
value did not reflect the let defined at the original
position. We now detect this and will print the
value verbatim, instead of the reference.

The different locations in the error messages for
issue 3801 are related to the nodes now being
shared. This is not necessarily bad, although
perhaps not ideal. This would be a big change
to do correctly, though.

Fixes #3938
Issue #3801

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: Ie90fe457feb2552d69ad63e8788752bb9b070110
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1215601
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

Author: mpvl

cue/testdata/benchmarks/issue2176.txtar

@@ -65,11 +65,11 @@ Allocs: 449
 Retain: 0
 
 Unifications: 377
-Conjuncts:    1527
+Conjuncts:    1333
 Disjuncts:    8
 
 CloseIDElems: 134
-NumCloseIDs: 731
+NumCloseIDs: 537
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
 --- old
@@ -91,11 +91,11 @@ diff old new
 +Retain: 0
 +
 +Unifications: 377
-+Conjuncts:    1527
++Conjuncts:    1333
 +Disjuncts:    8
 +
 +CloseIDElems: 134
-+NumCloseIDs: 731
++NumCloseIDs: 537
 -- out/eval/stats --
 Leaks:  90
 Freed:  746

cue/testdata/definitions/typocheck.txtar

@@ -448,18 +448,18 @@ full: {
 	out: (#Main & {namespace: "ns1"}).output
 }
 -- out/evalalpha/stats --
-Leaks:  739
+Leaks:  738
 Freed:  0
 Reused: 0
-Allocs: 739
+Allocs: 738
 Retain: 0
 
-Unifications: 611
-Conjuncts:    1199
+Unifications: 615
+Conjuncts:    1193
 Disjuncts:    45
 
-CloseIDElems: 1839
-NumCloseIDs: 395
+CloseIDElems: 1859
+NumCloseIDs: 386
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
 --- old
@@ -474,18 +474,18 @@ diff old new
 -Unifications: 918
 -Conjuncts:    1892
 -Disjuncts:    1189
-+Leaks:  739
++Leaks:  738
 +Freed:  0
 +Reused: 0
-+Allocs: 739
++Allocs: 738
 +Retain: 0
 +
-+Unifications: 611
-+Conjuncts:    1199
++Unifications: 615
++Conjuncts:    1193
 +Disjuncts:    45
 +
-+CloseIDElems: 1839
-+NumCloseIDs: 395
++CloseIDElems: 1859
++NumCloseIDs: 386
 -- out/eval/stats --
 Leaks:  115
 Freed:  879
@@ -1351,7 +1351,7 @@ Result:
           op: (string){ "add" }
           path: (string){ "/metadata" }
           value: (_|_){
-            // [incomplete] full.#Resource.patches.0.value: invalid interpolation: non-concrete value string (type string):
+            // [incomplete] full.#Resource.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
             //     ./large.cue:7:25
             //     ./large.cue:3:12
           }
@@ -1380,7 +1380,7 @@ Result:
     #Main: (#struct){
       namespace: (string){ string }
       output: (_|_){
-        // [incomplete] full.#Main.output: key value of dynamic field must be concrete, found string:
+        // [incomplete] full.#Main.jsonPatch.output: key value of dynamic field must be concrete, found string:
         //     ./large.cue:21:24
         //     ./large.cue:19:15
       }
@@ -1403,7 +1403,7 @@ Result:
               op: (string){ "add" }
               path: (string){ "/metadata" }
               value: (_|_){
-                // [incomplete] full.#Main.jsonPatch.base.patches.0.value: invalid interpolation: non-concrete value string (type string):
+                // [incomplete] full.#Main.jsonPatch.base.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
                 //     ./large.cue:7:25
                 //     ./large.cue:3:12
               }
@@ -2159,12 +2159,21 @@ diff old new
      }
      #Foo: (#struct){
        foo?: ((null|struct)){ |(*(#struct){
+@@ -983,7 +852,7 @@
+           op: (string){ "add" }
+           path: (string){ "/metadata" }
+           value: (_|_){
+-            // [incomplete] full.#Resource.patches.0.value: invalid interpolation: non-concrete value string (type string):
++            // [incomplete] full.#Resource.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
+             //     ./large.cue:7:25
+             //     ./large.cue:3:12
+           }
 @@ -1012,38 +881,11 @@
      #Main: (#struct){
        namespace: (string){ string }
        output: (_|_){
 -        // [incomplete] full.#Main.output: invalid non-ground value string (must be concrete string):
-+        // [incomplete] full.#Main.output: key value of dynamic field must be concrete, found string:
++        // [incomplete] full.#Main.jsonPatch.output: key value of dynamic field must be concrete, found string:
 +        //     ./large.cue:21:24
          //     ./large.cue:19:15
 -        //     ./large.cue:41:15
@@ -2200,6 +2209,15 @@ diff old new
          let base#6 = (#struct){
            someMsg: (string){ string }
            obs: (#struct){ |(*(#struct){
+@@ -1062,7 +904,7 @@
+               op: (string){ "add" }
+               path: (string){ "/metadata" }
+               value: (_|_){
+-                // [incomplete] full.#Main.jsonPatch.base.patches.0.value: invalid interpolation: non-concrete value string (type string):
++                // [incomplete] full.#Main.jsonPatch.base.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
+                 //     ./large.cue:7:25
+                 //     ./large.cue:3:12
+               }
 @@ -1086,6 +928,19 @@
              }
            }

cue/testdata/eval/bulk.txtar

@@ -140,18 +140,18 @@ issue3638: compare: {
 	#x: { a: int } | *{ b: 2 }
 }
 -- out/evalalpha/stats --
-Leaks:  332
+Leaks:  302
 Freed:  0
 Reused: 0
-Allocs: 332
+Allocs: 302
 Retain: 0
 
-Unifications: 248
-Conjuncts:    487
-Disjuncts:    63
+Unifications: 229
+Conjuncts:    453
+Disjuncts:    53
 
-CloseIDElems: 1023
-NumCloseIDs: 130
+CloseIDElems: 121
+NumCloseIDs: 125
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
 --- old
@@ -166,18 +166,18 @@ diff old new
 -Unifications: 214
 -Conjuncts:    639
 -Disjuncts:    297
-+Leaks:  332
++Leaks:  302
 +Freed:  0
 +Reused: 0
-+Allocs: 332
++Allocs: 302
 +Retain: 0
 +
-+Unifications: 248
-+Conjuncts:    487
-+Disjuncts:    63
++Unifications: 229
++Conjuncts:    453
++Disjuncts:    53
 +
-+CloseIDElems: 1023
-+NumCloseIDs: 130
++CloseIDElems: 121
++NumCloseIDs: 125
 -- out/eval/stats --
 Leaks:  4
 Freed:  269

cue/testdata/eval/issue3801.txtar

@@ -97,18 +97,18 @@ issue3801: nonRooted: full: {
 	}
 }
 -- out/evalalpha/stats --
-Leaks:  269
+Leaks:  266
 Freed:  0
 Reused: 0
-Allocs: 269
+Allocs: 266
 Retain: 0
 
-Unifications: 178
-Conjuncts:    355
+Unifications: 181
+Conjuncts:    346
 Disjuncts:    16
 
-CloseIDElems: 130
-NumCloseIDs: 94
+CloseIDElems: 151
+NumCloseIDs: 83
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
 --- old
@@ -123,18 +123,18 @@ diff old new
 -Unifications: 599
 -Conjuncts:    1319
 -Disjuncts:    762
-+Leaks:  269
++Leaks:  266
 +Freed:  0
 +Reused: 0
-+Allocs: 269
++Allocs: 266
 +Retain: 0
 +
-+Unifications: 178
-+Conjuncts:    355
++Unifications: 181
++Conjuncts:    346
 +Disjuncts:    16
 +
-+CloseIDElems: 130
-+NumCloseIDs: 94
++CloseIDElems: 151
++NumCloseIDs: 83
 -- out/eval/stats --
 Leaks:  237
 Freed:  408
@@ -191,7 +191,7 @@ Disjuncts:    762
               op: (string){ "add" }
               path: (string){ "/metadata" }
               value: (_|_){
-                // [incomplete] issue3801.let.full.#Resource.patches.0.value: invalid interpolation: non-concrete value string (type string):
+                // [incomplete] issue3801.let.full.#Resource.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
                 //     ./nested.cue:29:25
                 //     ./nested.cue:25:12
               }
@@ -220,7 +220,7 @@ Disjuncts:    762
         #Main: (#struct){
           namespace: (string){ string }
           output: (_|_){
-            // [incomplete] issue3801.let.full.#Main.output: key value of dynamic field must be concrete, found string:
+            // [incomplete] issue3801.let.full.#Main.jsonPatch.output: key value of dynamic field must be concrete, found string:
             //     ./nested.cue:43:24
             //     ./nested.cue:41:15
           }
@@ -243,7 +243,7 @@ Disjuncts:    762
                   op: (string){ "add" }
                   path: (string){ "/metadata" }
                   value: (_|_){
-                    // [incomplete] issue3801.let.full.#Main.jsonPatch.base.patches.0.value: invalid interpolation: non-concrete value string (type string):
+                    // [incomplete] issue3801.let.full.#Main.jsonPatch.base.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
                     //     ./nested.cue:29:25
                     //     ./nested.cue:25:12
                   }
@@ -355,12 +355,21 @@ Disjuncts:    762
 diff old new
 --- old
 +++ new
+@@ -43,7 +43,7 @@
+               op: (string){ "add" }
+               path: (string){ "/metadata" }
+               value: (_|_){
+-                // [incomplete] issue3801.let.full.#Resource.patches.0.value: invalid interpolation: non-concrete value string (type string):
++                // [incomplete] issue3801.let.full.#Resource.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
+                 //     ./nested.cue:29:25
+                 //     ./nested.cue:25:12
+               }
 @@ -72,38 +72,11 @@
          #Main: (#struct){
            namespace: (string){ string }
            output: (_|_){
 -            // [incomplete] issue3801.let.full.#Main.output: invalid non-ground value string (must be concrete string):
-+            // [incomplete] issue3801.let.full.#Main.output: key value of dynamic field must be concrete, found string:
++            // [incomplete] issue3801.let.full.#Main.jsonPatch.output: key value of dynamic field must be concrete, found string:
 +            //     ./nested.cue:43:24
              //     ./nested.cue:41:15
 -            //     ./nested.cue:63:15
@@ -396,6 +405,15 @@ diff old new
              let base#8 = (#struct){
                someMsg: (string){ string }
                obs: (#struct){ |(*(#struct){
+@@ -122,7 +95,7 @@
+                   op: (string){ "add" }
+                   path: (string){ "/metadata" }
+                   value: (_|_){
+-                    // [incomplete] issue3801.let.full.#Main.jsonPatch.base.patches.0.value: invalid interpolation: non-concrete value string (type string):
++                    // [incomplete] issue3801.let.full.#Main.jsonPatch.base.pickMsg.msg: invalid interpolation: non-concrete value string (type string):
+                     //     ./nested.cue:29:25
+                     //     ./nested.cue:25:12
+                   }
 @@ -146,6 +119,19 @@
                  }
                }

cue/testdata/eval/letjoin.txtar

@@ -138,12 +138,12 @@ Reused: 0
 Allocs: 212
 Retain: 0
 
-Unifications: 138
-Conjuncts:    359
+Unifications: 139
+Conjuncts:    353
 Disjuncts:    36
 
 CloseIDElems: 14
-NumCloseIDs: 93
+NumCloseIDs: 86
 -- diff/-out/evalalpha/stats<==>+out/eval/stats --
 diff old new
 --- old
@@ -164,12 +164,12 @@ diff old new
 +Allocs: 212
 +Retain: 0
 +
-+Unifications: 138
-+Conjuncts:    359
++Unifications: 139
++Conjuncts:    353
 +Disjuncts:    36
 +
 +CloseIDElems: 14
-+NumCloseIDs: 93
++NumCloseIDs: 86
 -- out/eval/stats --
 Leaks:  28
 Freed:  215