docs: improve e build --target documentation (#635)

* docs: improve e build --target documentation

* Update README.md

Co-authored-by: David Sanders <dsanders11@ucsbalum.com>

* refactor: remove build aliases

---------

Co-authored-by: David Sanders <dsanders11@ucsbalum.com>

README.md

@@ -195,20 +195,58 @@ $ e build --help
 ```
 
 Once you have the source, the next step is to build it with `e build [target]`.
-These build targets are supported:
+Some of the build targets you may want to build include:
 
 | Target        | Description                                              |
 |:--------------|:---------------------------------------------------------|
-| breakpad      | Builds the breakpad `dump_syms` binary                   |
-| chromedriver  | Builds the `chromedriver` binary                         |
-| electron      | Builds the Electron binary **(Default)**                 |
-| electron:dist | Builds the Electron binary and generates a dist zip file |
-| mksnapshot    | Builds the `mksnapshot` binary                           |
-| node:headers  | Builds the node headers `.tar.gz` file                   |
+| third_party/breakpad:dump_syms      | Builds the breakpad `dump_syms` binary                   |
+| electron:electron_chromedriver_zip  | Builds the `chromedriver` binary                         |
+| electron                            | Builds the Electron binary **(Default)**                 |
+| electron:electron_dist_zip          | Builds the Electron binary and generates a dist zip file |
+| electron:electron_mksnapshot_zip    | Builds the `mksnapshot` binary                           |
+| electron:node_headers               | Builds the node headers `.tar.gz` file                   |
+| electron:electron_symbols           | Generate the breakpad symbols in release builds          |
 
-As with syncing, `e build [target]` is usually all you need. Any extra
-args are passed along to [ninja][ninja], so for example `e build -v`
-runs a verbose build.
+To build a specific ninja target, run `e build --target [target]`:
+
+```sh
+$ e build --target electron:node_headers
+```
+
+Running `e build` with no target will build `electron` by default.
+
+Any extra args are passed along to [ninja][ninja], so for example
+`e build -v` runs a verbose build of `electron`.
+
+To see an exhaustive list of all possible build targets, you can run `e d gn ls out/[TYPE]`,
+where `[TYPE]` is e.g. `Testing` or `Release` depending on your build type. This will log a long
+list of targets to the console and also allow you to build some of Chromium's targets.
+
+For example, running `e d gn ls out/Testing | grep "//ui/views/"` produces something like:
+
+```console
+//ui/views/controls/webview:test_support
+//ui/views/controls/webview:webview
+//ui/views/debug:views_debug
+//ui/views/examples:copy_content_resources
+//ui/views/examples:views_examples
+//ui/views/examples:views_examples_lib
+//ui/views/examples:views_examples_proc
+//ui/views/examples:views_examples_resources_grd
+//ui/views/examples:views_examples_resources_grd_grit
+//ui/views/examples:views_examples_resources_pak
+//ui/views/examples:views_examples_unittests
+//ui/views/examples:views_examples_unittests__runner
+//ui/views/examples:views_examples_with_content
+//ui/views/examples:views_examples_with_content_lib
+//ui/views/resources:resources
+//ui/views/resources:resources_grd
+//ui/views/resources:resources_grd_grit
+//ui/views/window/vector_icons:vector_icons
+//ui/views/window/vector_icons:window_control_vector_icons
+```
+
+You could then run `e build --target ui/views/examples:views_examples_with_content` to produce Chrome's `//ui/views` example executable and run it with `./out/Testing/views_examples_with_content`.
 
 ## Using Electron
 

src/e-build.js

@@ -86,34 +86,25 @@ function runNinja(config, target, ninjaArgs) {
 }
 
 program
-  .arguments('[target] [ninjaArgs...]')
+  .arguments('[ninjaArgs...]')
   .description('Build Electron and other targets.')
-  .option('--list-targets', 'Show all supported build targets', false)
   .option('--only-gen', 'Only run `gn gen`', false)
-  .option('-t|--target [target]', 'Forces a specific ninja target')
+  .option('-t|--target [target]', 'Build a specific ninja target')
   .option('--no-remote', 'Build without remote execution (entirely locally)')
   .allowUnknownOption()
-  .action((target, ninjaArgs, options) => {
+  .action((ninjaArgs, options) => {
     try {
       const config = evmConfig.current();
-      const targets = evmConfig.buildTargets();
 
       reclient.usingRemote = options.remote;
 
       reclient.downloadAndPrepare(config);
 
-      if (options.listTargets) {
-        Object.keys(targets)
-          .sort()
-          .forEach(target => console.log(`${target} --> ${color.config(targets[target])}`));
-        return;
-      }
-
       if (process.platform === 'darwin') {
         if (config.onlySdk) {
           ensureSDK();
         } else {
-          loadXcode({ target, quiet: true });
+          loadXcode({ quiet: true });
         }
       }
 
@@ -122,37 +113,8 @@ program
         return;
       }
 
-      if (options.target) {
-        // User forced a target, so any arguments are ninjaArgs
-        if (target) {
-          ninjaArgs.unshift(target);
-        }
-        target = options.target;
-      } else if (Object.keys(targets).includes(target)) {
-        target = targets[target];
-      } else {
-        // No forced target and no target matched, so use the
-        // default target and assume any arguments are ninjaArgs
-        if (target) {
-          ninjaArgs.unshift(target);
-        }
-        target = targets['default'];
-      }
-
-      try {
-        runNinja(config, target, ninjaArgs);
-      } catch (ex) {
-        if (target === targets['node:headers']) {
-          // Older versions of electron use a different target for node headers so try that if the new one fails.
-          const olderTarget = 'third_party/electron_node:headers';
-          console.info(
-            `${color.info} Error building ${target}; trying older ${olderTarget} target`,
-          );
-          runNinja(config, olderTarget, ninjaArgs);
-        } else {
-          throw ex;
-        }
-      }
+      const buildTarget = options.target || evmConfig.getDefaultTarget();
+      runNinja(config, buildTarget, ninjaArgs);
     } catch (e) {
       fatal(e);
     }

src/e-sync.js

@@ -77,7 +77,7 @@ function runGClientSync(syncArgs, syncOpts) {
   }
 
   // Only set remotes if we're building an Electron target.
-  if (config.defaultTarget !== evmConfig.buildTargets().chromium) {
+  if (config.defaultTarget !== 'chrome') {
     const electronPath = path.resolve(srcdir, 'electron');
     setRemotes(electronPath, config.remotes.electron);
   }

src/evm-config.js

@@ -32,17 +32,6 @@ const getDefaultTarget = () => {
   return result || 'electron';
 };
 
-const buildTargets = () => ({
-  breakpad: 'third_party/breakpad:dump_syms',
-  chromedriver: 'electron:electron_chromedriver_zip',
-  electron: 'electron',
-  chromium: 'chrome',
-  'electron:dist': 'electron:electron_dist_zip',
-  mksnapshot: 'electron:electron_mksnapshot_zip',
-  'node:headers': 'electron:node_headers',
-  default: getDefaultTarget(),
-});
-
 function buildPath(name, suffix) {
   return path.resolve(configRoot(), `evm.${name}.${suffix}`);
 }
@@ -319,7 +308,7 @@ function remove(name) {
 }
 
 module.exports = {
-  buildTargets,
+  getDefaultTarget,
   current: () => sanitizeConfigWithName(currentName()),
   maybeCurrent: () => (getCurrentFileName() ? sanitizeConfigWithName(currentName()) : {}),
   currentName,

src/utils/load-xcode.js

@@ -10,7 +10,6 @@ const Xcode = require('./xcode');
 const evmConfig = require('../evm-config');
 
 function loadXcode(options = {}) {
-  const target = options.target || 'electron';
   const quiet = options.quiet || false;
 
   if (process.platform !== 'darwin') {