common/compiler: remove workaround for solc 0.3.5 stdin bug (#3522)

The crash when compiling stdin was fixed in solc 0.3.6 (released
2016-08-10). While here, simplify the test so it runs with any solc
version.

Fixes #3484. The byte code was different for each run because recent
solc embeds the swarm hash of contract metadata into the code. When
compiling from stdin the name in the metadata is constant.

common/compiler/solidity.go

@@ -22,9 +22,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"io/ioutil"
-	"os"
 	"os/exec"
 	"regexp"
 	"strings"
@@ -96,27 +94,16 @@ func CompileSolidityString(solc, source string) (map[string]*Contract, error) {
 	if solc == "" {
 		solc = "solc"
 	}
-	// Write source to a temporary file. Compiling stdin used to be supported
-	// but seems to produce an exception with solc 0.3.5.
-	infile, err := ioutil.TempFile("", "geth-compile-solidity")
-	if err != nil {
-		return nil, err
-	}
-	defer os.Remove(infile.Name())
-	if _, err := io.WriteString(infile, source); err != nil {
-		return nil, err
-	}
-	if err := infile.Close(); err != nil {
-		return nil, err
-	}
-
-	return CompileSolidity(solc, infile.Name())
+	args := append(solcParams, "--")
+	cmd := exec.Command(solc, append(args, "-")...)
+	cmd.Stdin = strings.NewReader(source)
+	return runsolc(cmd, source)
 }
 
 // CompileSolidity compiles all given Solidity source files.
 func CompileSolidity(solc string, sourcefiles ...string) (map[string]*Contract, error) {
 	if len(sourcefiles) == 0 {
-		return nil, errors.New("solc: no source ")
+		return nil, errors.New("solc: no source files")
 	}
 	source, err := slurpFiles(sourcefiles)
 	if err != nil {
@@ -125,10 +112,13 @@ func CompileSolidity(solc string, sourcefiles ...string) (map[string]*Contract,
 	if solc == "" {
 		solc = "solc"
 	}
-
-	var stderr, stdout bytes.Buffer
 	args := append(solcParams, "--")
 	cmd := exec.Command(solc, append(args, sourcefiles...)...)
+	return runsolc(cmd, source)
+}
+
+func runsolc(cmd *exec.Cmd, source string) (map[string]*Contract, error) {
+	var stderr, stdout bytes.Buffer
 	cmd.Stderr = &stderr
 	cmd.Stdout = &stdout
 	if err := cmd.Run(); err != nil {

common/compiler/solidity_test.go

@@ -20,6 +20,7 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"os"
+	"os/exec"
 	"path"
 	"testing"
 
@@ -27,8 +28,7 @@ import (
 )
 
 const (
-	supportedSolcVersion = "0.3.5"
-	testSource           = `
+	testSource = `
 contract test {
    /// @notice Will multiply ` + "`a`" + ` by 7.
    function multiply(uint a) returns(uint d) {
@@ -36,23 +36,18 @@ contract test {
    }
 }
 `
-	testCode = "0x6060604052602a8060106000396000f3606060405260e060020a6000350463c6888fa18114601a575b005b6007600435026060908152602090f3"
 	testInfo = `{"source":"\ncontract test {\n   /// @notice Will multiply ` + "`a`" + ` by 7.\n   function multiply(uint a) returns(uint d) {\n       return a * 7;\n   }\n}\n","language":"Solidity","languageVersion":"0.1.1","compilerVersion":"0.1.1","compilerOptions":"--binary file --json-abi file --natspec-user file --natspec-dev file --add-std 1","abiDefinition":[{"constant":false,"inputs":[{"name":"a","type":"uint256"}],"name":"multiply","outputs":[{"name":"d","type":"uint256"}],"type":"function"}],"userDoc":{"methods":{"multiply(uint256)":{"notice":"Will multiply ` + "`a`" + ` by 7."}}},"developerDoc":{"methods":{}}}`
 )
 
-func skipUnsupported(t *testing.T) {
-	sol, err := SolidityVersion("")
-	if err != nil {
+func skipWithoutSolc(t *testing.T) {
+	if _, err := exec.LookPath("solc"); err != nil {
 		t.Skip(err)
-		return
-	}
-	if sol.Version != supportedSolcVersion {
-		t.Skipf("unsupported version of solc found (%v, expect %v)", sol.Version, supportedSolcVersion)
 	}
 }
 
 func TestCompiler(t *testing.T) {
-	skipUnsupported(t)
+	skipWithoutSolc(t)
+
 	contracts, err := CompileSolidityString("", testSource)
 	if err != nil {
 		t.Fatalf("error compiling source. result %v: %v", contracts, err)
@@ -64,19 +59,20 @@ func TestCompiler(t *testing.T) {
 	if !ok {
 		t.Fatal("info for contract 'test' not present in result")
 	}
-	if c.Code != testCode {
-		t.Errorf("wrong code: expected\n%s, got\n%s", testCode, c.Code)
+	if c.Code == "" {
+		t.Error("empty code")
 	}
 	if c.Info.Source != testSource {
 		t.Error("wrong source")
 	}
-	if c.Info.CompilerVersion != supportedSolcVersion {
-		t.Errorf("wrong version: expected %q, got %q", supportedSolcVersion, c.Info.CompilerVersion)
+	if c.Info.CompilerVersion == "" {
+		t.Error("empty version")
 	}
 }
 
 func TestCompileError(t *testing.T) {
-	skipUnsupported(t)
+	skipWithoutSolc(t)
+
 	contracts, err := CompileSolidityString("", testSource[4:])
 	if err == nil {
 		t.Errorf("error expected compiling source. got none. result %v", contracts)