add prover_disabled build tag to compile without prover

.github/workflows/lint-witness.yaml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   lint:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5

.github/workflows/test-linux-default.yaml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         go-version: [ 1.18.x ]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - name: Install Go
         if: success()
@@ -29,4 +29,3 @@ jobs:
         run: cat /proc/cpuinfo
       - name: Run tests
         run: cd tests && go test -v -covermode=count
-

.github/workflows/test-linux-noasm.yaml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         go-version: [ 1.18.x ]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     steps:
       - name: Install Go
         if: success()

.github/workflows/test-witness.yaml

@@ -14,7 +14,7 @@ jobs:
           - 1.21.13
           - 1.22.7
           - 1.23.1
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     container: golang:${{matrix.containers}}
     steps:
       - uses: actions/checkout@v4

prover/rapidsnark.go

@@ -1,3 +1,5 @@
+//go:build !prover_disabled
+
 package prover
 
 /*

prover/rapidsnark_mock.go

@@ -0,0 +1,19 @@
+//go:build prover_disabled
+
+package prover
+
+import (
+	"errors"
+
+	"github.com/iden3/go-rapidsnark/types"
+)
+
+// Groth16Prover generates proof and returns proof and pubsignals as types.ZKProof
+func Groth16Prover(zkey []byte, witness []byte) (proof *types.ZKProof, err error) {
+	return nil, errors.New("prover disabled: 'prover_disabled' build flag was passed")
+}
+
+// Groth16ProverRaw generates proof and returns proof and pubsignals as json string
+func Groth16ProverRaw(zkey []byte, witness []byte) (proof string, publicInputs string, err error) {
+	return "", "", errors.New("prover disabled: 'prover_disabled' build flag was passed")
+}