feat: implement slog-based logging

.github/workflows/pr.yml

@@ -11,7 +11,7 @@ permissions:
 env:
   ABIGEN_VERSION: v1.14.8
   GO_VERSION: 1.25.x # NB! when updating also update matrix, we cannot refer to env variables in the matrix
-  GOLANGCI_LINT_VERSION: v2.10.1
+  GOLANGCI_LINT_VERSION: v2.12.2
 
 jobs:
   staticcheck:

.github/workflows/push.yml

@@ -14,7 +14,7 @@ permissions:
 env:
   ABIGEN_VERSION: v1.14.8
   GO_VERSION: 1.25.x # NB! when updating also update matrix, we cannot refer to env variables in the matrix
-  GOLANGCI_LINT_VERSION: v2.10.1
+  GOLANGCI_LINT_VERSION: v2.12.2
 
 jobs:
   staticcheck:

.golangci.yml

@@ -9,6 +9,7 @@ linters:
     - govet
     - ineffassign
     - misspell
+    - sloglint
   settings:
     staticcheck:
       checks:
@@ -20,6 +21,15 @@ linters:
       excludes:
         - G115
         - G602
+    sloglint:
+      attr-only: true
+      no-mixed-args: true
+      static-msg: true
+      no-global: all
+      custom-funcs:
+        - name: github.com/consensys/gnark/internal/logger.Trace
+          msg-pos: 1
+          args-pos: 2
   exclusions:
     generated: disable
     presets:

README.md

@@ -46,6 +46,19 @@ go run ./examples/cubic
 
 To design your first circuit, follow the tutorial in [`gnark` User Documentation].
 
+## Logging
+
+`gnark` reads `GNARK_LOG_LEVEL` to configure internal logs:
+
+- `trace`: logs all records and includes source locations.
+- `debug`: logs debug records and startup runtime/build metadata.
+- `info`: logs info records and above. This is the default.
+- `warning` or `warn`: logs warning records and above.
+- `error`: logs error records only.
+- `quiet` or `none`: disables logs.
+
+When built with the `debug` build tag and `GNARK_LOG_LEVEL` is unset, the default level is `debug`.
+
 ## Supported Proving Systems and Curves
 
 `gnark` currently supports: