Prevent module from closing when proc_exit is called with a 0 exit …

…code.

Signed-off-by: Phil Kedy <[email protected]>

imports/wasi_snapshot_preview1/proc.go

@@ -28,6 +28,10 @@ var procExit = &wasm.HostFunc{
 
 func procExitFn(ctx context.Context, mod api.Module, params []uint64) {
 	exitCode := uint32(params[0])
+	// TinyGo 0.35.0 calls proc_exit from _start, even for exit code 0.
+	if exitCode == 0 {
+		return
+	}
 
 	// Ensure other callers see the exit code.
 	_ = mod.CloseWithExitCode(ctx, exitCode)

imports/wasi_snapshot_preview1/proc_test.go

@@ -19,11 +19,9 @@ func Test_procExit(t *testing.T) {
 		expectedLog string
 	}{
 		{
-			name:     "success (exitcode 0)",
-			exitCode: 0,
-			expectedLog: `
-==> wasi_snapshot_preview1.proc_exit(rval=0)
-`,
+			name:        "success (exitcode 0)",
+			exitCode:    0,
+			expectedLog: ``,
 		},
 		{
 			name:     "arbitrary non-zero exitcode",
@@ -42,11 +40,15 @@ func Test_procExit(t *testing.T) {
 
 			// Since procExit panics, any opcodes afterwards cannot be reached.
 			_, err := mod.ExportedFunction(wasip1.ProcExitName).Call(testCtx, uint64(tc.exitCode))
-			require.Error(t, err)
-			sysErr, ok := err.(*sys.ExitError)
-			require.True(t, ok, err)
-			require.Equal(t, tc.exitCode, sysErr.ExitCode())
-			require.Equal(t, tc.expectedLog, "\n"+log.String())
+			if tc.expectedLog != "" {
+				require.Error(t, err)
+				sysErr, ok := err.(*sys.ExitError)
+				require.True(t, ok, err)
+				require.Equal(t, tc.exitCode, sysErr.ExitCode())
+				require.Equal(t, tc.expectedLog, "\n"+log.String())
+			} else {
+				require.NoError(t, err)
+			}
 		})
 	}
 }