add diff-contract command

Author: janezpodhostnik

README.md

@@ -54,12 +54,13 @@ Usage:
   transactions Build, sign, send and retrieve transactions
 
 🔨 Flow Tools
-  cadence      Execute Cadence code
-  dev-wallet   Run a development wallet
-  emulator     Run Flow network for development
-  flix         execute, generate, package
-  flowser      Run Flowser project explorer
-  test         Run Cadence tests
+  cadence        Execute Cadence code
+  dev-wallet     Run a development wallet
+  diff-contract  Diff a local contract against a deployed one
+  emulator       Run Flow network for development
+  flix           execute, generate, package
+  flowser        Run Flowser project explorer
+  test           Run Cadence tests
 
 🏄 Flow Project
   deploy       Deploy all project contracts

cmd/flow/main.go

@@ -31,6 +31,7 @@ import (
 	"github.com/onflow/flow-cli/internal/command"
 	"github.com/onflow/flow-cli/internal/config"
 	"github.com/onflow/flow-cli/internal/dependencymanager"
+	"github.com/onflow/flow-cli/internal/diffcontract"
 	"github.com/onflow/flow-cli/internal/emulator"
 	"github.com/onflow/flow-cli/internal/events"
 	evm "github.com/onflow/flow-cli/internal/evm"
@@ -67,6 +68,7 @@ func main() {
 	tools.DevWallet.AddToParent(cmd)
 	tools.Flowser.AddToParent(cmd)
 	test.TestCommand.AddToParent(cmd)
+	diffcontract.DiffContractCommand.AddToParent(cmd)
 
 	// super commands
 	super.InitCommand.AddToParent(cmd)

go.mod

@@ -30,6 +30,7 @@ require (
 	github.com/onflowser/flowser/v3 v3.2.1-0.20240131200229-7d4d22715f48
 	github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c
 	github.com/pkg/errors v0.9.1
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2
 	github.com/psiemens/sconfig v0.1.0
 	github.com/radovskyb/watcher v1.0.7
 	github.com/rs/zerolog v1.35.0
@@ -228,7 +229,6 @@ require (
 	github.com/pion/transport/v2 v2.2.10 // indirect
 	github.com/pion/transport/v3 v3.0.7 // indirect
 	github.com/pkg/term v1.2.0-beta.2 // indirect
-	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_golang v1.23.2 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.66.1 // indirect

internal/diffcontract/diff-contract.go

@@ -0,0 +1,263 @@
+/*
+ * Flow CLI
+ *
+ * Copyright Flow Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package diffcontract
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/pmezard/go-difflib/difflib"
+	"github.com/spf13/cobra"
+
+	flowsdk "github.com/onflow/flow-go-sdk"
+
+	"github.com/onflow/flowkit/v2"
+	"github.com/onflow/flowkit/v2/output"
+	"github.com/onflow/flowkit/v2/project"
+
+	"github.com/onflow/flow-cli/internal/command"
+	"github.com/onflow/flow-cli/internal/util"
+)
+
+type diffContractFlags struct {
+	Quiet bool `default:"false" flag:"quiet" info:"Exit with non-zero code if contracts differ, without output"`
+}
+
+var diffFlags = diffContractFlags{}
+
+var DiffContractCommand = &command.Command{
+	Cmd: &cobra.Command{
+		Use:     "diff-contract <file-or-url> [address]",
+		Short:   "Diff a local contract against a deployed one",
+		Example: "flow diff-contract ./MyContract.cdc\nflow diff-contract ./MyContract.cdc 0xf8d6e0586b0a20c7\nflow diff-contract https://example.com/MyContract.cdc my-account --network testnet",
+		Args:    cobra.RangeArgs(1, 2),
+		GroupID: "tools",
+	},
+	Flags: &diffFlags,
+	RunS:  diffContract,
+}
+
+func init() {
+	DiffContractCommand.Cmd.Flags().BoolVarP(&diffFlags.Quiet, "quiet", "q", false, "Exit with non-zero code if contracts differ, without output")
+}
+
+func diffContract(
+	args []string,
+	globalFlags command.GlobalFlags,
+	logger output.Logger,
+	flow flowkit.Services,
+	state *flowkit.State,
+) (command.Result, error) {
+	source := args[0]
+
+	// Read source code from file or URL
+	var code []byte
+	var location string
+	var err error
+
+	if strings.HasPrefix(source, "http://") || strings.HasPrefix(source, "https://") {
+		code, err = fetchURL(source)
+		if err != nil {
+			return nil, fmt.Errorf("error fetching contract from URL: %w", err)
+		}
+		location = source
+	} else {
+		code, err = state.ReadFile(source)
+		if err != nil {
+			return nil, fmt.Errorf("error loading contract file: %w", err)
+		}
+		location = source
+	}
+
+	// Extract contract name from source
+	program, err := project.NewProgram(code, nil, location)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing contract source: %w", err)
+	}
+
+	contractName, err := program.Name()
+	if err != nil {
+		return nil, fmt.Errorf("error extracting contract name: %w", err)
+	}
+
+	// Resolve imports in source code
+	ctx := context.Background()
+	resolved, err := flow.ReplaceImportsInScript(ctx, flowkit.Script{
+		Code:     code,
+		Location: location,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("error resolving imports: %w", err)
+	}
+
+	// Resolve target address: from argument or from flow.json deployments
+	var address flowsdk.Address
+	if len(args) >= 2 {
+		address, err = util.ResolveAddressOrAccountNameForNetworks(args[1], state, []string{globalFlags.Network})
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		address, err = resolveAddressFromConfig(state, contractName, globalFlags.Network)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// Fetch deployed contract
+	logger.StartProgress(fmt.Sprintf("Fetching contract '%s' from %s...", contractName, address))
+	defer logger.StopProgress()
+
+	account, err := flow.GetAccount(ctx, address)
+	if err != nil {
+		return nil, fmt.Errorf("error fetching account: %w", err)
+	}
+
+	deployedCode, ok := account.Contracts[contractName]
+	if !ok {
+		return nil, fmt.Errorf("contract '%s' not found on account %s", contractName, address)
+	}
+
+	// Normalize and diff
+	localCode := util.NormalizeLineEndings(string(resolved.Code))
+	remoteCode := util.NormalizeLineEndings(string(deployedCode))
+
+	identical := localCode == remoteCode
+
+	exitCode := 0
+	if !identical {
+		exitCode = 1
+	}
+
+	diffText := ""
+	if !identical {
+		localLabel := source
+		remoteLabel := fmt.Sprintf("0x%s/%s (deployed)", address, contractName)
+		diff := difflib.UnifiedDiff{
+			A:        difflib.SplitLines(remoteCode),
+			B:        difflib.SplitLines(localCode),
+			FromFile: remoteLabel,
+			ToFile:   localLabel,
+			Context:  3,
+		}
+		diffText, err = difflib.GetUnifiedDiffString(diff)
+		if err != nil {
+			return nil, fmt.Errorf("error computing diff: %w", err)
+		}
+	}
+
+	return &diffContractResult{
+		diff:         diffText,
+		contractName: contractName,
+		address:      address.String(),
+		identical:    identical,
+		quiet:        diffFlags.Quiet,
+		exitCode:     exitCode,
+	}, nil
+}
+
+// resolveAddressFromConfig looks up the address for a contract in flow.json
+// by checking deployments first, then contract aliases for the given network.
+func resolveAddressFromConfig(state *flowkit.State, contractName string, network string) (flowsdk.Address, error) {
+	// Check deployments
+	deployments := state.Deployments().ByNetwork(network)
+	for _, deployment := range deployments {
+		for _, contract := range deployment.Contracts {
+			if contract.Name == contractName {
+				account, err := state.Accounts().ByName(deployment.Account)
+				if err != nil {
+					return flowsdk.EmptyAddress, fmt.Errorf("account '%s' from deployment not found in configuration: %w", deployment.Account, err)
+				}
+				return account.Address, nil
+			}
+		}
+	}
+
+	// Check contract aliases
+	contract, err := state.Contracts().ByName(contractName)
+	if err == nil && contract != nil {
+		if alias := contract.Aliases.ByNetwork(network); alias != nil {
+			return alias.Address, nil
+		}
+	}
+
+	return flowsdk.EmptyAddress, fmt.Errorf("contract '%s' not found in deployments or aliases for network '%s' in flow.json, specify an address explicitly", contractName, network)
+}
+
+func fetchURL(url string) ([]byte, error) {
+	resp, err := http.Get(url) //nolint:gosec
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, resp.Status)
+	}
+
+	return io.ReadAll(resp.Body)
+}
+
+// diffContractResult implements command.ResultWithExitCode
+type diffContractResult struct {
+	diff         string
+	contractName string
+	address      string
+	identical    bool
+	quiet        bool
+	exitCode     int
+}
+
+var _ command.ResultWithExitCode = &diffContractResult{}
+
+func (r *diffContractResult) String() string {
+	if r.quiet {
+		return ""
+	}
+	if r.identical {
+		return fmt.Sprintf("Contract '%s' on 0x%s is up to date", r.contractName, r.address)
+	}
+	return r.diff
+}
+
+func (r *diffContractResult) Oneliner() string {
+	if r.identical {
+		return "identical"
+	}
+	return "different"
+}
+
+func (r *diffContractResult) JSON() any {
+	result := map[string]any{
+		"contract":  r.contractName,
+		"address":   r.address,
+		"identical": r.identical,
+	}
+	if !r.identical {
+		result["diff"] = r.diff
+	}
+	return result
+}
+
+func (r *diffContractResult) ExitCode() int {
+	return r.exitCode
+}