ES|QL: Make FUSE available in release builds

docs/changelog/135603.yaml

@@ -0,0 +1,5 @@
+pr: 135603
+summary: Make FUSE available in release builds
+area: ES|QL
+type: feature
+issues: []

x-pack/plugin/esql/qa/testFixtures/src/main/resources/fuse.csv-spec

@@ -363,8 +363,7 @@ fuseWithLinearAndL2Norm
 
 required_capability: fork_v9
 required_capability: fuse_v6
-required_capability: semantic_text_field_caps
-required_capability: metadata_score
+required_capability: fuse_l2_norm
 
 FROM books METADATA _id, _index, _score
 | FORK ( WHERE title:"Tolkien" | SORT _score, _id DESC | LIMIT 3 )
@@ -658,6 +657,7 @@ id_0.0      | 0.0
 fuseWithRowLinearAndL2Norm
 
 required_capability: fuse_v6
+required_capability: fuse_l2_norm
 
 ROW my_score = [0, 1, 2, 3, 4]::double, _index = "my_index", _fork = "foo"
 | MV_EXPAND my_score
@@ -759,6 +759,7 @@ id_4.0      | 0.01563         | foo
 fuseWithRowLinearL2NormAndZeroScores
 
 required_capability: fuse_v6
+required_capability: fuse_l2_norm
 
 ROW _id = ["a", "b", "c"], _score = 0.0, _index = "my_index", my_fork = "foo"
 | MV_EXPAND _id

x-pack/plugin/esql/src/internalClusterTest/java/org/elasticsearch/xpack/esql/action/FuseIT.java

@@ -137,6 +137,8 @@ public void testFuseSimpleLinear() {
     }
 
     public void testFuseLinearWithWeightsAndNormalizer() {
+        assumeTrue("requires FUSE_L2_NORM capability", EsqlCapabilities.Cap.FUSE_L2_NORM.isEnabled());
+
         var query = """
             FROM test METADATA _score, _id, _index
             | WHERE id > 2

x-pack/plugin/esql/src/main/antlr/EsqlBaseParser.g4

@@ -66,10 +66,10 @@ processingCommand
     | forkCommand
     | rerankCommand
     | inlineStatsCommand
+    | fuseCommand
     // in development
     | {this.isDevVersion()}? lookupCommand
     | {this.isDevVersion()}? insistCommand
-    | {this.isDevVersion()}? fuseCommand
     ;
 
 whereCommand
@@ -326,6 +326,17 @@ inlineStatsCommand
     | INLINESTATS stats=aggFields (BY grouping=fields)?
     ;
 
+fuseCommand
+    : FUSE (fuseType=identifier)? (fuseConfiguration)*
+    ;
+
+fuseConfiguration
+    : SCORE BY score=qualifiedName
+    | KEY BY key=fields
+    | GROUP BY group=qualifiedName
+    | WITH options=mapExpression
+    ;
+
 //
 // In development
 //
@@ -337,17 +348,6 @@ insistCommand
     : DEV_INSIST qualifiedNamePatterns
     ;
 
-fuseCommand
-    : DEV_FUSE (fuseType=identifier)? (fuseConfiguration)*
-    ;
-
-fuseConfiguration
-    : SCORE BY score=qualifiedName
-    | KEY BY key=fields
-    | GROUP BY group=qualifiedName
-    | WITH options=mapExpression
-    ;
-
 setCommand
     : SET setField SEMICOLON
     ;

x-pack/plugin/esql/src/main/antlr/lexer/Fuse.g4

@@ -7,7 +7,7 @@
 
 lexer grammar Fuse;
 
-DEV_FUSE : {this.isDevVersion()}? 'fuse' -> pushMode(FUSE_MODE);
+FUSE : 'fuse' -> pushMode(FUSE_MODE);
 
 mode FUSE_MODE;
 FUSE_PIPE : PIPE -> type(PIPE), popMode;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -1372,7 +1372,7 @@ public enum Cap {
         /**
          * FUSE command
          */
-        FUSE_V6(Build.current().isSnapshot()),
+        FUSE_V6,
 
         /**
          * Support improved behavior for LIKE operator when used with index fields.
@@ -1560,6 +1560,11 @@ public enum Cap {
 
         DENSE_VECTOR_AGG_METRIC_DOUBLE_IF_FNS,
 
+        /**
+         * FUSE L2_NORM score normalization support
+         */
+        FUSE_L2_NORM(Build.current().isSnapshot()),
+
         /**
          * Support for requesting the "_tsid" metadata field.
          */