Update the signature of vector script functions. (#48604)

Previously the functions accepted a doc values reference, whereas they now
accept the name of the vector field. Here's an example of how a vector function
was called before and after the change.

```
Before: cosineSimilarity(params.query_vector, doc['field'])
After:  cosineSimilarity(params.query_vector, 'field')
```

This seems more intuitive, since we don't allow direct access to vector doc
values and the the meaning of `doc['field']` is unclear.

The PR makes the following changes (broken into distinct commits):
* Add new function signatures of the form `function(params.query_vector,
'field')` and deprecates the old ones. Because Painless doesn't allow two
methods with the same name and number of arguments, we allow a generic `Object`
to be passed in to the function and decide on the behavior through an
`instanceof` check.
* Refactor the class bindings so that the document field is passed to the
constructor instead of the instance method. This allows us to avoid retrieving
the vector doc values on every function invocation, which gives a tiny speed-up
in benchmarks.

Note that this PR adds new signatures for the sparse vector functions too, even
though sparse vectors are deprecated. It seemed simplest to understand (for both
us and users) to keep everything symmetric between dense and sparse vectors.

docs/painless/painless-api-reference/painless-api-reference-score/index.asciidoc

@@ -10,8 +10,8 @@ The following specialized API is available in the Score context.
 ==== Static Methods
 The following methods are directly callable without a class/instance qualifier. Note parameters denoted by a (*) are treated as read-only values.
 
-* double cosineSimilarity(List *, VectorScriptDocValues.DenseVectorScriptDocValues)
-* double cosineSimilaritySparse(Map *, VectorScriptDocValues.SparseVectorScriptDocValues)
+* double cosineSimilarity(List *, String)
+* double cosineSimilaritySparse(Map *, String)
 * double decayDateExp(String *, String *, String *, double *, JodaCompatibleZonedDateTime)
 * double decayDateGauss(String *, String *, String *, double *, JodaCompatibleZonedDateTime)
 * double decayDateLinear(String *, String *, String *, double *, JodaCompatibleZonedDateTime)
@@ -21,8 +21,8 @@ The following methods are directly callable without a class/instance qualifier.
 * double decayNumericExp(double *, double *, double *, double *, double)
 * double decayNumericGauss(double *, double *, double *, double *, double)
 * double decayNumericLinear(double *, double *, double *, double *, double)
-* double dotProduct(List, VectorScriptDocValues.DenseVectorScriptDocValues)
-* double dotProductSparse(Map *, VectorScriptDocValues.SparseVectorScriptDocValues)
+* double dotProduct(List, String)
+* double dotProductSparse(Map *, String)
 * double randomScore(int *)
 * double randomScore(int *, String *)
 * double saturation(double, double)

docs/reference/vectors/vector-functions.asciidoc

@@ -68,7 +68,7 @@ GET my_index/_search
         }
       },
       "script": {
-        "source": "cosineSimilarity(params.query_vector, doc['my_dense_vector']) + 1.0", <2>
+        "source": "cosineSimilarity(params.query_vector, 'my_dense_vector') + 1.0", <2>
         "params": {
           "query_vector": [4, 3.4, -0.2]  <3>
         }
@@ -105,7 +105,7 @@ GET my_index/_search
       },
       "script": {
         "source": """
-          double value = dotProduct(params.query_vector, doc['my_dense_vector']);
+          double value = dotProduct(params.query_vector, 'my_dense_vector');
           return sigmoid(1, Math.E, -value); <1>
         """,
         "params": {
@@ -139,7 +139,7 @@ GET my_index/_search
         }
       },
       "script": {
-        "source": "1 / (1 + l1norm(params.queryVector, doc['my_dense_vector']))", <1>
+        "source": "1 / (1 + l1norm(params.queryVector, 'my_dense_vector'))", <1>
         "params": {
           "queryVector": [4, 3.4, -0.2]
         }
@@ -178,7 +178,7 @@ GET my_index/_search
         }
       },
       "script": {
-        "source": "1 / (1 + l2norm(params.queryVector, doc['my_dense_vector']))",
+        "source": "1 / (1 + l2norm(params.queryVector, 'my_dense_vector'))",
         "params": {
           "queryVector": [4, 3.4, -0.2]
         }
@@ -196,7 +196,7 @@ You can check if a document has a value for the field `my_vector` by
 
 [source,js]
 --------------------------------------------------
-"source": "doc['my_vector'].size() == 0 ? 0 : cosineSimilarity(params.queryVector, doc['my_vector'])"
+"source": "doc['my_vector'].size() == 0 ? 0 : cosineSimilarity(params.queryVector, 'my_vector')"
 --------------------------------------------------
 // NOTCONSOLE
 
@@ -262,7 +262,7 @@ GET my_sparse_index/_search
         }
       },
       "script": {
-        "source": "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector']) + 1.0",
+        "source": "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector') + 1.0",
         "params": {
           "query_vector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
         }
@@ -294,7 +294,7 @@ GET my_sparse_index/_search
       },
       "script": {
         "source": """
-          double value = dotProductSparse(params.query_vector, doc['my_sparse_vector']);
+          double value = dotProductSparse(params.query_vector, 'my_sparse_vector');
           return sigmoid(1, Math.E, -value);
         """,
          "params": {
@@ -327,7 +327,7 @@ GET my_sparse_index/_search
         }
       },
       "script": {
-        "source": "1 / (1 + l1normSparse(params.queryVector, doc['my_sparse_vector']))",
+        "source": "1 / (1 + l1normSparse(params.queryVector, 'my_sparse_vector'))",
         "params": {
           "queryVector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
         }
@@ -358,7 +358,7 @@ GET my_sparse_index/_search
         }
       },
       "script": {
-        "source": "1 / (1 + l2normSparse(params.queryVector, doc['my_sparse_vector']))",
+        "source": "1 / (1 + l2normSparse(params.queryVector, 'my_sparse_vector'))",
         "params": {
           "queryVector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
         }

server/src/main/java/org/elasticsearch/script/ScoreScript.java

@@ -109,7 +109,7 @@ public Map<String, Object> getParams() {
     }
 
     /** The doc lookup for the Lucene segment this script was created for. */
-    public final Map<String, ScriptDocValues<?>> getDoc() {
+    public Map<String, ScriptDocValues<?>> getDoc() {
         return leafLookup.doc();
     }
 

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/10_dense_vector_basic.yml

@@ -1,6 +1,6 @@
 setup:
   - skip:
-      features: headers
+      features: [headers, warnings]
       version: " - 7.2.99"
       reason: "dense_vector functions were added from 7.3"
 
@@ -52,7 +52,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "dotProduct(params.query_vector, doc['my_dense_vector'])"
+                source: "dotProduct(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [0.5, 111.3, -13.0, 14.8, -156.0]
 
@@ -82,7 +82,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+                source: "cosineSimilarity(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [0.5, 111.3, -13.0, 14.8, -156.0]
 
@@ -99,3 +99,26 @@ setup:
   - match: {hits.hits.2._id: "1"}
   - gte: {hits.hits.2._score: 0.78}
   - lte: {hits.hits.2._score: 0.791}
+
+---
+"Deprecated function signature":
+  - do:
+      headers:
+        Content-Type: application/json
+      warnings:
+        - The vector functions of the form function(query, doc['field']) are deprecated, and the form function(query, 'field')` should be used instead. For example, cosineSimilarity(query, doc['field'] is replaced by cosineSimilarity(query, 'field').
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            script_score:
+              query: {match_all: {} }
+              script:
+                source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+                params:
+                  query_vector: [0.5, 111.3, -13.0, 14.8, -156.0]
+
+  - match: {hits.total: 3}
+  - match: {hits.hits.0._id: "3"}
+  - match: {hits.hits.1._id: "2"}
+  - match: {hits.hits.2._id: "1"}

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/15_dense_vector_l1l2.yml

@@ -53,7 +53,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "l1norm(params.query_vector, doc['my_dense_vector'])"
+                source: "l1norm(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [0.5, 111.3, -13.0, 14.8, -156.0]
 
@@ -83,7 +83,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "l2norm(params.query_vector, doc['my_dense_vector'])"
+                source: "l2norm(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [0.5, 111.3, -13.0, 14.8, -156.0]
 

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/20_dense_vector_special_cases.yml

@@ -62,7 +62,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+                source: "cosineSimilarity(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [10, 10, 10]
 
@@ -81,7 +81,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+                source: "cosineSimilarity(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [10.0, 10.0, 10.0]
 
@@ -111,7 +111,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+                source: "cosineSimilarity(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [1, 2, 3, 4]
   - match: { error.root_cause.0.type: "script_exception" }
@@ -125,7 +125,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "dotProduct(params.query_vector, doc['my_dense_vector'])"
+                source: "dotProduct(params.query_vector, 'my_dense_vector')"
                 params:
                   query_vector: [1, 2, 3, 4]
   - match: { error.root_cause.0.type: "script_exception" }
@@ -161,7 +161,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+              source: "cosineSimilarity(params.query_vector, 'my_dense_vector')"
               params:
                 query_vector: [10.0, 10.0, 10.0]
 - match: { error.root_cause.0.type: "script_exception" }
@@ -177,7 +177,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "doc['my_dense_vector'].size() == 0 ? 0 : cosineSimilarity(params.query_vector, doc['my_dense_vector'])"
+              source: "doc['my_dense_vector'].size() == 0 ? 0 : cosineSimilarity(params.query_vector, 'my_dense_vector')"
               params:
                 query_vector: [10.0, 10.0, 10.0]
 
@@ -209,7 +209,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "dotProductSparse(params.query_vector, doc['my_dense_vector'])"
+              source: "dotProductSparse(params.query_vector, 'my_dense_vector')"
               params:
                 query_vector: {"2": 0.5, "10" : 111.3, "3": 44}
 - match: { error.root_cause.0.type: "script_exception" }

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/30_sparse_vector_basic.yml

@@ -55,7 +55,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "dotProductSparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "dotProductSparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"2": 0.5, "10" : 111.3, "50": -13.0, "113": 14.8, "4545": -156.0}
 
@@ -87,7 +87,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"2": -0.5, "10" : 111.3, "50": -13.0, "113": 14.8, "4545": -156.0}
 
@@ -104,3 +104,27 @@ setup:
 - match: {hits.hits.2._id: "1"}
 - gte: {hits.hits.2._score: 0.78}
 - lte: {hits.hits.2._score: 0.791}
+
+---
+"Deprecated function signature":
+  - do:
+      headers:
+        Content-Type: application/json
+      warnings:
+        - The [sparse_vector] field type is deprecated and will be removed in 8.0.
+        - The vector functions of the form function(query, doc['field']) are deprecated, and the form function(query, 'field')` should be used instead. For example, cosineSimilarity(query, doc['field'] is replaced by cosineSimilarity(query, 'field').
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            script_score:
+              query: {match_all: {} }
+              script:
+                source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+                params:
+                  query_vector: {"2": -0.5, "10" : 111.3, "50": -13.0, "113": 14.8, "4545": -156.0}
+
+  - match: {hits.total: 3}
+  - match: {hits.hits.0._id: "3"}
+  - match: {hits.hits.1._id: "2"}
+  - match: {hits.hits.2._id: "1"}

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/35_sparse_vector_l1l2.yml

@@ -55,7 +55,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "l1normSparse(params.query_vector, doc['my_sparse_vector'])"
+                source: "l1normSparse(params.query_vector, 'my_sparse_vector')"
                 params:
                   query_vector: {"2": 0.5, "10" : 111.3, "50": -13.0, "113": 14.8, "4545": -156.0}
 
@@ -88,7 +88,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "l2normSparse(params.query_vector, doc['my_sparse_vector'])"
+                source: "l2normSparse(params.query_vector, 'my_sparse_vector')"
                 params:
                   query_vector: {"2": 0.5, "10" : 111.3, "50": -13.0, "113": 14.8, "4545": -156.0}
 

x-pack/plugin/src/test/resources/rest-api-spec/test/vectors/40_sparse_vector_special_cases.yml

@@ -61,7 +61,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+                source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
                 params:
                   query_vector: {"1": 10}
 
@@ -83,7 +83,7 @@ setup:
             script_score:
               query: {match_all: {} }
               script:
-                source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+                source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
                 params:
                   query_vector: {"1": 10.0}
 
@@ -127,7 +127,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10.0}
 - match: { error.root_cause.0.type: "script_exception" }
@@ -145,7 +145,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "doc['my_sparse_vector'].size() == 0 ? 0 : cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "doc['my_sparse_vector'].size() == 0 ? 0 : cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10.0}
 
@@ -194,7 +194,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"100": -200.0, "11" : 300.33, "12": -34.8988, "2": 230.0, "30": 15.555}
 
@@ -230,7 +230,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "dotProduct(params.query_vector, doc['my_sparse_vector'])"
+              source: "dotProduct(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: [0.5, 111]
 - match: { error.root_cause.0.type: "script_exception" }
@@ -273,7 +273,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "dotProductSparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "dotProductSparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10, "5": 5}
 
@@ -304,7 +304,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "cosineSimilaritySparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10, "5" : 5}
 
@@ -334,7 +334,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "l1normSparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "l1normSparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10, "5": 5}
 
@@ -361,7 +361,7 @@ setup:
           script_score:
             query: {match_all: {} }
             script:
-              source: "l2normSparse(params.query_vector, doc['my_sparse_vector'])"
+              source: "l2normSparse(params.query_vector, 'my_sparse_vector')"
               params:
                 query_vector: {"1": 10, "5": 5}