Allow enabling backtraces

tests/spec/features/backtrace_spec.rb

@@ -1,26 +1,45 @@
 require 'spec_helper'
 require 'support/editor'
+require 'support/playground_actions'
 
 RSpec.feature "A backtrace is shown for certain errors", type: :feature, js: true do
-  before { pending "Backtracing has a large performance penalty" }
+  include PlaygroundActions
 
   before do
     visit '/'
     editor.set(code)
-    within('.header') { click_on("Run") }
   end
 
-  scenario "a stack trace is shown" do
-    within('.output-stderr') do
-      expect(page).to have_content 'stack backtrace:'
-      expect(page).to have_content 'rust_begin_unwind'
+  context "backtraces are enabled" do
+    before do
+      in_advanced_options_menu { choose 'enabled' }
+      within('.header') { click_on("Run") }
+    end
+
+    scenario "a backtrace is shown" do
+      within('.output-stderr') do
+        expect(page).to have_content 'stack backtrace:'
+        expect(page).to have_content 'rust_begin_unwind'
+      end
+    end
+
+    scenario "filenames link to that line of code" do
+      within('.output-stderr') do
+        expect(page).to have_link('main.rs:2')
+        expect(page).to have_link('main.rs:6')
+      end
     end
   end
 
-  scenario "filenames link to that line of code" do
-    within('.output-stderr') do
-      expect(page).to have_link('main.rs:2')
-      expect(page).to have_link('main.rs:6')
+  context "backtraces are disabled" do
+    before do
+      within('.header') { click_on("Run") }
+    end
+
+    scenario "the backtrace suggestion is a link" do
+      within('.output-stderr') do
+        expect(page).to have_link(text: /Run with .* a backtrace/)
+      end
     end
   end
 

ui/frontend/AdvancedOptionsMenu.tsx

@@ -1,19 +1,22 @@
 import React, { Fragment } from 'react';
 import { connect } from 'react-redux';
 
-import { changeEdition } from './actions';
+import { changeBacktrace, changeEdition } from './actions';
 import { changeNightlyEdition } from './actions';
 import { Either as EitherConfig } from './ConfigElement';
 import MenuGroup from './MenuGroup';
 import { State } from './reducers';
-import { getEditionSet, isEditionAvailable } from './selectors';
-import { Edition } from './types';
+import { getBacktraceSet, getEditionSet, isEditionAvailable } from './selectors';
+import { Backtrace, Edition } from './types';
 
 interface AdvancedOptionsMenuProps {
   edition: Edition;
   isEditionSet: boolean;
   isEditionAvailable: boolean;
   changeEdition: (_: Edition) => any;
+  backtrace: Backtrace;
+  isBacktraceSet: boolean;
+  changeBacktrace: (_: Backtrace) => any;
 }
 
 const AdvancedOptionsMenu: React.SFC<AdvancedOptionsMenuProps> = props => (
@@ -28,6 +31,15 @@ const AdvancedOptionsMenu: React.SFC<AdvancedOptionsMenuProps> = props => (
         isNotDefault={props.isEditionSet}
         onChange={props.changeEdition} />
       {!props.isEditionAvailable && <EditionAside />}
+
+      <EitherConfig
+        id="backtrace"
+        name="Backtrace"
+        a={Backtrace.Disabled}
+        b={Backtrace.Enabled}
+        value={props.backtrace}
+        isNotDefault={props.isBacktraceSet}
+        onChange={props.changeBacktrace} />
     </MenuGroup>
   </Fragment>
 );
@@ -43,10 +55,13 @@ const mapStateToProps = (state: State) => ({
   isEditionSet: getEditionSet(state),
   edition: state.configuration.edition,
   isEditionAvailable: isEditionAvailable(state),
+  isBacktraceSet: getBacktraceSet(state),
+  backtrace: state.configuration.backtrace,
 });
 
 const mapDispatchToProps = ({
   changeEdition: changeNightlyEdition,
+  changeBacktrace,
 });
 
 export default connect(mapStateToProps, mapDispatchToProps)(AdvancedOptionsMenu);

ui/frontend/actions.ts

@@ -6,6 +6,7 @@ import { getCrateType, isEditionAvailable, runAsTest } from './selectors';
 import State from './state';
 import {
   AssemblyFlavor,
+  Backtrace,
   Channel,
   DemangleAssembly,
   Edition,
@@ -51,6 +52,7 @@ export enum ActionType {
   ChangeProcessAssembly = 'CHANGE_PROCESS_ASSEMBLY',
   ChangeMode = 'CHANGE_MODE',
   ChangeEdition = 'CHANGE_EDITION',
+  ChangeBacktrace = 'CHANGE_BACKTRACE',
   ChangeFocus = 'CHANGE_FOCUS',
   ExecuteRequest = 'EXECUTE_REQUEST',
   ExecuteSucceeded = 'EXECUTE_SUCCEEDED',
@@ -131,6 +133,14 @@ export const changeNightlyEdition = (edition: Edition): ThunkAction => dispatch
   dispatch(changeEdition(edition));
 };
 
+export const changeBacktrace = (backtrace: Backtrace) =>
+  createAction(ActionType.ChangeBacktrace, { backtrace });
+
+export const reExecuteWithBacktrace = (): ThunkAction => dispatch => {
+  dispatch(changeBacktrace(Backtrace.Enabled));
+  dispatch(performExecute());
+};
+
 export const changeFocus = focus =>
   createAction(ActionType.ChangeFocus, { focus });
 
@@ -184,6 +194,7 @@ interface ExecuteRequestBody {
   tests: boolean;
   code: string;
   edition?: string;
+  backtrace: boolean;
 }
 
 export function performExecute(): ThunkAction {
@@ -195,8 +206,9 @@ export function performExecute(): ThunkAction {
     const { code, configuration: { channel, mode, edition } } = state;
     const crateType = getCrateType(state);
     const tests = runAsTest(state);
+    const backtrace = state.configuration.backtrace === Backtrace.Enabled;
 
-    const body: ExecuteRequestBody = { channel, mode, crateType, tests, code };
+    const body: ExecuteRequestBody = { channel, mode, crateType, tests, code, backtrace };
     if (isEditionAvailable(state)) {
       body.edition = edition;
     }
@@ -230,6 +242,7 @@ function performCompile(target, { request, success, failure }): ThunkAction {
     } } = state;
     const crateType = getCrateType(state);
     const tests = runAsTest(state);
+    const backtrace = state.configuration.backtrace === Backtrace.Enabled;
     const body: CompileRequestBody = {
       channel,
       mode,
@@ -240,6 +253,7 @@ function performCompile(target, { request, success, failure }): ThunkAction {
       assemblyFlavor,
       demangleAssembly,
       processAssembly,
+      backtrace,
     };
     if (isEditionAvailable(state)) {
       body.edition = edition;
@@ -569,6 +583,7 @@ export type Action =
   | ReturnType<typeof changeKeybinding>
   | ReturnType<typeof changeMode>
   | ReturnType<typeof changeEdition>
+  | ReturnType<typeof changeBacktrace>
   | ReturnType<typeof changeOrientation>
   | ReturnType<typeof changeTheme>
   | ReturnType<typeof requestExecute>

ui/frontend/highlighting.ts

@@ -1,6 +1,6 @@
 import Prism from 'prismjs';
 
-export function configureRustErrors({ gotoPosition, getChannel }) {
+export function configureRustErrors({ gotoPosition, reExecuteWithBacktrace, getChannel }) {
   Prism.languages.rust_errors = { // eslint-disable-line camelcase
     'warning': /^warning:.*$/m,
     'error': {
@@ -11,7 +11,13 @@ export function configureRustErrors({ gotoPosition, getChannel }) {
       },
     },
     'error-location': /-->.*\n/,
-    'stack-trace-location': /at \/playground.*\n/,
+    'backtrace': {
+      pattern: /at src\/.*\n/,
+      inside: {
+        'backtrace-location': /src\/main.rs:(\d+)/,
+      },
+    },
+    'backtrace-enable': /Run with `RUST_BACKTRACE=1` for a backtrace/,
   };
 
   Prism.hooks.add('wrap', env => {
@@ -37,8 +43,13 @@ export function configureRustErrors({ gotoPosition, getChannel }) {
       env.attributes['data-line'] = line;
       env.attributes['data-col'] = col;
     }
-    if (env.type === 'stack-trace-location') {
-      const errorMatch = /main.rs:(\d+)/.exec(env.content);
+    if (env.type === 'backtrace-enable') {
+      env.tag = 'a';
+      env.attributes.href = '#';
+      env.attributes['data-backtrace-enable'] = 'true';
+    }
+    if (env.type === 'backtrace-location') {
+      const errorMatch = /:(\d+)/.exec(env.content);
       const [_, line] = errorMatch;
       env.tag = 'a';
       env.attributes.href = '#';
@@ -48,13 +59,21 @@ export function configureRustErrors({ gotoPosition, getChannel }) {
   });
 
   Prism.hooks.add('after-highlight', env => {
-    const links = env.element.querySelectorAll('.error-location, .stack-trace-location');
+    const links = env.element.querySelectorAll('.error-location, .backtrace-location');
     Array.from(links).forEach((link: HTMLAnchorElement) => {
       const { line, col } = link.dataset;
       link.onclick = e => {
         e.preventDefault();
         gotoPosition(line, col);
       };
     });
+
+    const backtraceEnablers = env.element.querySelectorAll('.backtrace-enable');
+    Array.from(backtraceEnablers).forEach((link: HTMLAnchorElement) => {
+      link.onclick = e => {
+        e.preventDefault();
+        reExecuteWithBacktrace();
+      };
+    });
   });
 }

ui/frontend/index.tsx

@@ -8,13 +8,14 @@ import persistState from 'redux-localstorage';
 import thunk, { ThunkDispatch } from 'redux-thunk';
 import * as url from 'url';
 
-import { Action, gotoPosition, performCratesLoad, performVersionsLoad } from './actions';
+import { Action, gotoPosition, performCratesLoad, performVersionsLoad, reExecuteWithBacktrace } from './actions';
 import { configureRustErrors } from './highlighting';
 import { deserialize, serialize } from './local_storage';
 import PageSwitcher from './PageSwitcher';
 import playgroundApp from './reducers';
 import { State } from './reducers';
 import Router from './Router';
+import { Backtrace } from './types';
 
 const baseUrl = url.resolve(window.location.href, '/');
 
@@ -31,6 +32,7 @@ const store = createStore(playgroundApp, initialState, enhancers);
 
 configureRustErrors({
   gotoPosition: (line, col) => store.dispatch(gotoPosition(line, col)),
+  reExecuteWithBacktrace: () => store.dispatch(reExecuteWithBacktrace()),
   getChannel: () => store.getState().configuration.channel,
 });
 

ui/frontend/reducers/configuration.ts

@@ -1,6 +1,7 @@
 import { Action, ActionType } from '../actions';
 import {
   AssemblyFlavor,
+  Backtrace,
   Channel,
   DemangleAssembly,
   Edition,
@@ -22,6 +23,7 @@ export interface State {
   channel: Channel;
   mode: Mode;
   edition: Edition;
+  backtrace: Backtrace;
 }
 
 export const DEFAULT: State = {
@@ -36,6 +38,7 @@ export const DEFAULT: State = {
   channel: Channel.Stable,
   mode: Mode.Debug,
   edition: Edition.Rust2015,
+  backtrace: Backtrace.Disabled,
 };
 
 export default function configuration(state = DEFAULT, action: Action): State {
@@ -75,6 +78,8 @@ export default function configuration(state = DEFAULT, action: Action): State {
       }
       return { ...state, edition: action.edition };
     }
+    case ActionType.ChangeBacktrace:
+      return { ...state, backtrace: action.backtrace };
     default:
       return state;
   }

ui/frontend/selectors/index.ts

@@ -3,7 +3,7 @@ import { createSelector } from 'reselect';
 import * as url from 'url';
 
 import { State } from '../reducers';
-import { Channel, Edition } from '../types';
+import { Backtrace, Channel, Edition } from '../types';
 
 const getCode = state => state.code;
 
@@ -53,14 +53,21 @@ export const getChannelLabel = (state: State) => {
   return `${channel}`;
 };
 
-export const getAdvancedOptionsSet = (state: State) => (
-  getEditionSet(state)
-);
-
 export const getEditionSet = (state: State) => (
   state.configuration.edition !== Edition.Rust2015
 );
 
+export const getBacktraceSet = (state: State) => (
+  state.configuration.backtrace !== Backtrace.Disabled
+);
+
+export const getAdvancedOptionsSet = createSelector(
+  getEditionSet, getBacktraceSet,
+  (editionSet, backtraceSet) => (
+    editionSet || backtraceSet
+  ),
+);
+
 const baseUrlSelector = (state: State) =>
   state.globalConfiguration.baseUrl;
 

ui/frontend/types.ts

@@ -66,3 +66,8 @@ export enum Edition {
   Rust2015 = '2015',
   Rust2018 = '2018',
 }
+
+export enum Backtrace {
+  Disabled = 'disabled',
+  Enabled = 'enabled',
+}

ui/src/main.rs

@@ -525,6 +525,7 @@ struct CompileRequest {
     #[serde(rename = "crateType")]
     crate_type: String,
     tests: bool,
+    backtrace: bool,
     code: String,
 }
 
@@ -545,6 +546,7 @@ struct ExecuteRequest {
     #[serde(rename = "crateType")]
     crate_type: String,
     tests: bool,
+    backtrace: bool,
     code: String,
 }
 
@@ -657,6 +659,7 @@ impl TryFrom<CompileRequest> for sandbox::CompileRequest {
             edition: parse_edition(&me.edition)?,
             crate_type: parse_crate_type(&me.crate_type)?,
             tests: me.tests,
+            backtrace: me.backtrace,
             code: me.code,
         })
     }
@@ -683,6 +686,7 @@ impl TryFrom<ExecuteRequest> for sandbox::ExecuteRequest {
             edition: parse_edition(&me.edition)?,
             crate_type: try!(parse_crate_type(&me.crate_type)),
             tests: me.tests,
+            backtrace: me.backtrace,
             code: me.code,
         })
     }
@@ -779,6 +783,7 @@ impl TryFrom<EvaluateRequest> for sandbox::ExecuteRequest {
             edition: None, // FIXME: What should this be?
             crate_type: sandbox::CrateType::Binary,
             tests: false,
+            backtrace: false,
             code: me.code,
         })
     }