dance around DCE issues (#37)

project.clj

@@ -159,10 +159,12 @@
                                                    ["test-tests"]
                                                    ["test-tests-with-config"]
                                                    ["test-dead-code"]
+                                                   ["test-dce-size"]
                                                    ["test-advanced-warning"]]
             "test-dead-code"                      ["do"
                                                    ["with-profile" "+testing" "cljsbuild" "once" "dead-code"]
                                                    ["shell" "test/scripts/dead-code-check.sh"]]
+            "test-dce-size"                       ["shell" "scripts/check-dce-size.sh" "+testing"]
             "compare-dead-code"                   ["shell" "scripts/compare-dead-code.sh" "+testing"]
             "compare-dead-code-with-pseudo-names" ["shell" "scripts/compare-dead-code.sh" "+testing,+dce-pseudo-names"]
             "test-tests"                          ["do"

scripts/check-dce-size.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+
+set -e
+
+pushd `dirname "${BASH_SOURCE[0]}"` > /dev/null
+source "./config.sh"
+
+cd "$ROOT"
+
+if [[ -z "${SKIP_DCE_COMPILATION}" ]]; then
+  ./scripts/compile-dead-code.sh "$@"
+fi
+
+cd "$DCE_CACHE_DIR"
+
+NO_DEBUG_MAX_SIZE=6000
+NO_REQUIRE_MAX_SIZE=6000
+
+BUILD_WITH_DEBUG="$DCE_CACHE_DIR/with-debug.js"
+BUILD_NO_DEBUG="$DCE_CACHE_DIR/no-debug.js"
+BUILD_NO_MENTION="$DCE_CACHE_DIR/no-mention.js"
+BUILD_NO_REQUIRE="$DCE_CACHE_DIR/no-require.js"
+BUILD_NO_SOURCES="$DCE_CACHE_DIR/no-sources.js"
+
+WITH_DEBUG_SIZE=$(stat -f %z "$BUILD_WITH_DEBUG")
+NO_DEBUG_SIZE=$(stat -f %z "$BUILD_NO_DEBUG")
+NO_MENTION_SIZE=$(stat -f %z "$BUILD_NO_MENTION")
+NO_REQUIRE_SIZE=$(stat -f %z "$BUILD_NO_REQUIRE")
+NO_SOURCES_SIZE=$(stat -f %z "$BUILD_NO_SOURCES")
+
+echo
+echo "stats:"
+echo "WITH_DEBUG: $WITH_DEBUG_SIZE bytes"
+echo "NO_DEBUG:   $NO_DEBUG_SIZE bytes"
+echo "NO_MENTION: $NO_MENTION_SIZE bytes"
+echo "NO_REQUIRE: $NO_REQUIRE_SIZE bytes"
+echo "NO_SOURCES: $NO_SOURCES_SIZE bytes"
+echo
+
+if [[ "$NO_DEBUG_SIZE" != "$NO_MENTION_SIZE" ]]; then
+  echo "failure: NO_DEBUG and NO_MENTION expected to have the same size."
+  exit 1
+fi
+
+if [[ "$NO_REQUIRE_SIZE" != "$NO_SOURCES_SIZE" ]]; then
+  echo "failure: NO_REQUIRE and NO_SOURCES expected to have the same size."
+  exit 2
+fi
+
+if [[ "$NO_DEBUG_SIZE" -gt "$NO_DEBUG_MAX_SIZE" ]]; then
+  echo "failure: NO_DEBUG expected to have size smaller than $NO_DEBUG_MAX_SIZE bytes."
+  exit 3
+fi
+
+if [[ "$NO_REQUIRE_SIZE" -gt "$NO_REQUIRE_MAX_SIZE" ]]; then
+  echo "failure: NO_REQUIRE_SIZE expected to have size smaller than $NO_REQUIRE_MAX_SIZE bytes."
+  exit 4
+fi
+
+popd

src/lib/devtools/core.cljs

@@ -20,7 +20,7 @@
 (defn available?
   ([] (available? (prefs/pref :features-to-install)))
   ([features-desc]
-   (let [features (resolve-features! features-desc feature-groups)]
+   (let [features (resolve-features! features-desc @feature-groups)]
      (if (empty? features)
        false
        (every? is-feature-available? features)))))
@@ -34,7 +34,7 @@
 (defn installed?
   ([] (installed? (prefs/pref :features-to-install)))
   ([features-desc]
-   (let [features (resolve-features! features-desc feature-groups)]
+   (let [features (resolve-features! features-desc @feature-groups)]
      (if (empty? features)
        false
        (every? is-feature-installed? features)))))
@@ -44,8 +44,8 @@
   ([features-desc]
    (if (under-advanced-build?)
      (display-advanced-build-warning-if-needed!)
-     (let [features (resolve-features! features-desc feature-groups)]
-       (display-banner-if-needed! features feature-groups)
+     (let [features (resolve-features! features-desc @feature-groups)]
+       (display-banner-if-needed! features @feature-groups)
        (print-config-overrides-if-requested! "config overrides prior install:\n")
        (install-feature! :formatters features is-feature-available? formatters/install!)
        (install-feature! :hints features is-feature-available? hints/install!)

src/lib/devtools/formatters/templating.cljs

@@ -1,7 +1,6 @@
 (ns devtools.formatters.templating
-  (:require [cljs.pprint]
-            [clojure.walk :refer [prewalk]]
-            [devtools.util :refer-macros [oget oset ocall oapply safe-call]]
+  (:require [clojure.walk :refer [prewalk]]
+            [devtools.util :refer-macros [oget oset ocall oapply safe-call] :refer [pprint-str]]
             [devtools.protocols :refer [ITemplate IGroup ISurrogate IFormat]]
             [devtools.formatters.helpers :refer [pref cljs-value?]]
             [devtools.formatters.state :refer [get-current-state prevent-recursion?]]
@@ -118,11 +117,6 @@
 (def ^:dynamic *current-render-stack* [])
 (def ^:dynamic *current-render-path* [])
 
-(defn pprint-str [markup]
-  (with-out-str
-    (binding [*print-level* 300]
-      (cljs.pprint/pprint markup))))
-
 (defn print-preview [markup]
   (binding [*print-level* 1]
     (pr-str markup)))

src/lib/devtools/hints.cljs

@@ -1,7 +1,11 @@
 (ns devtools.hints
+  (:require-macros [devtools.util :refer [emit-if-compiler-in-dev-mode]])
   (:require [devtools.prefs :refer [pref]]
             [devtools.context :as context]
-            [cljs.stacktrace :as stacktrace]))
+            [goog.string]                                                                                                     ; for cljs.stacktrace, see devtools.optional
+            [clojure.string]))                                                                                                ; for cljs.stacktrace, see devtools.optional
+
+(emit-if-compiler-in-dev-mode (goog/require "devtools.optional"))
 
 (defn ^:dynamic available? []
   true)
@@ -92,10 +96,16 @@
     (re-matches #"Cannot read property 'call' of.*" message) (mark-null-call-site-location file line-number column)
     :else nil))
 
+(defn parse-stacktrace [native-stack-trace]
+  ; note that we have to do dynamic lookup here, cljs.stacktrace is present only in dev mode
+  ; or when explicitly required by the user of cljs-devtools
+  (if (exists? js/devtools.optional.parse-stacktrace)
+    (js/devtools.optional.parse-stacktrace {} native-stack-trace {:ua-product :chrome} {:asset-root ""})))
+
 (defn error-object-sense [error]
   (try
     (let [native-stack-trace (.-stack error)
-          stack-trace (stacktrace/parse-stacktrace {} native-stack-trace {:ua-product :chrome} {:asset-root ""})
+          stack-trace (parse-stacktrace native-stack-trace)
           top-item (second stack-trace)                                                                                       ; first line is just an error message
           {:keys [file line column]} top-item]
       (make-sense-of-the-error (.-message error) file line column))

src/lib/devtools/munging.cljs

@@ -546,7 +546,7 @@
         name (last parts)]
     [ns name protocol-selector]))
 
-(def fast-path-protocols-lookup-table (get-fast-path-protocols-lookup-table))
+(def fast-path-protocols-lookup-table (delay (get-fast-path-protocols-lookup-table)))
 
 (defn key-for-protocol-partition [partition]
   (str "cljs$lang$protocol_mask$partition" partition "$"))
@@ -556,7 +556,7 @@
   (let [partition-key (key-for-protocol-partition partition)
         partition-bits (or (oget obj partition-key) 0)]
     (if (> partition-bits 0)
-      (let [lookup-table (get fast-path-protocols-lookup-table partition)
+      (let [lookup-table (get @fast-path-protocols-lookup-table partition)
             _ (assert (map? lookup-table)
                       (str "fast-path-protocols-lookup-table does not contain lookup table for partition " partition))
             * (fn [accum [bit protocol]]

src/lib/devtools/optional.cljs

@@ -0,0 +1,25 @@
+(ns devtools.optional
+  (:require [cljs.pprint]
+            [cljs.stacktrace]))
+
+; requires here do not play well with DCE in advanced mode
+; see https://github.com/binaryage/cljs-devtools/issues/37
+;
+; this file exists to be required dynamically in dev mode only via
+;   (emit-if-compiler-in-dev-mode (goog/require "devtools.optional"))
+;
+; we rely on the fact that in :none optimizations mode clojurescript compiler produces all js files
+; even if they are not reachable from :main namespace (if specified)
+;
+; please note that you should manually require namespaces which these requires depend on
+; to achieve correct ordering of requires for static code, currently goog.string and clojure.string
+
+; -- wrappers ---------------------------------------------------------------------------------------------------------------
+;
+; these are convenience wrappers, cljs.stacktrace/parse-stacktrace is a multi-method, so we couldn't call it directly from js
+
+(defn pprint [& args]
+  (apply cljs.pprint/pprint args))
+
+(defn parse-stacktrace [& args]
+  (apply cljs.stacktrace/parse-stacktrace args))

src/lib/devtools/prefs.cljs

@@ -2,37 +2,26 @@
   (:require-macros [devtools.prefs :refer [emit-external-config emit-env-config]])
   (:require [devtools.defaults :as defaults]))
 
-; we cannot use cljs.core/merge because that would confuse advanced mode compilation
-; if you look at cljs.core/merge you will see that it relies on reduce which relies on protocol checks and
-; this is probably too dymamic to be elided (my theory)
-(defn simple-merge [base-map & maps]
-  (let [rmaps (reverse maps)
-        sentinel (js-obj)
-        sentinel? #(identical? % sentinel)
-        merged-keys (dedupe (sort (apply concat (map keys rmaps))))]
-    (loop [result base-map
-           todo-keys merged-keys]
-      (if (empty? todo-keys)
-        result
-        (let [key (first todo-keys)
-              val (first (remove sentinel? (map #(get % key sentinel) rmaps)))]
-          (recur (assoc result key val) (rest todo-keys)))))))
-
-(def default-config defaults/prefs)
-(def external-config (emit-external-config))
-(def env-config (emit-env-config))
-(def initial-config (simple-merge default-config external-config env-config))
-
-(def ^:dynamic *prefs* initial-config)
+; we use delay for DCE, see https://github.com/binaryage/cljs-devtools/issues/37
+(def default-config (delay @defaults/config))
+(def external-config (delay (emit-external-config)))
+(def env-config (delay (emit-env-config)))
+(def initial-config (delay (merge @default-config @external-config @env-config)))
 
-(defn get-prefs []
-  *prefs*)
+(def ^:dynamic *current-config* (delay @initial-config))
 
-(defn pref [key]
-  (key *prefs*))
+; -- public api -------------------------------------------------------------------------------------------------------------
 
 (defn set-prefs! [new-prefs]
-  (set! *prefs* new-prefs))
+  (set! *current-config* new-prefs))
+
+(defn get-prefs []
+  (when (delay? *current-config*)
+    (set-prefs! @*current-config*))
+  *current-config*)
+
+(defn pref [key]
+  (key (get-prefs)))
 
 (defn set-pref! [key val]
   (set-prefs! (assoc (get-prefs) key val)))

src/lib/devtools/util.clj

@@ -29,3 +29,12 @@
      (~f ~@args)
      (catch :default e#
        ~exceptional-result)))
+
+(defn compiler-in-dev-mode? []
+  (if cljs.env/*compiler*
+    (let [mode (get-in @cljs.env/*compiler* [:options :optimizations])]
+      (and (not= mode :advanced) (not= mode :simple)))))
+
+(defmacro emit-if-compiler-in-dev-mode [body]
+  (if (compiler-in-dev-mode?)
+    body))

src/lib/devtools/util.cljs

@@ -1,13 +1,15 @@
 (ns devtools.util
-  (:require-macros [devtools.util :refer [oget ocall oset]])
+  (:require-macros [devtools.util :refer [oget ocall oset emit-if-compiler-in-dev-mode]])
   (:require [goog.userAgent :as ua]
             [clojure.data :as data]
-            [cljs.pprint :refer [pprint]]
             [devtools.version :refer [get-current-version]]
-            [devtools.defaults :as defaults]
             [devtools.context :as context]
+            [goog.string]                                                                                                     ; for cljs.pprint, see devtools.optional
+            [clojure.string]                                                                                                  ; for cljs.pprint, see devtools.optional
             [devtools.prefs :as prefs]))
 
+(emit-if-compiler-in-dev-mode (goog/require "devtools.optional"))
+
 (def lib-info-style "color:black;font-weight:bold;")
 (def reset-style "color:black")
 (def advanced-build-explanation-url
@@ -17,6 +19,17 @@
 (def ^:dynamic *console-open* false)
 (def ^:dynamic *custom-formatters-warning-reported* false)
 
+; -- general helpers --------------------------------------------------------------------------------------------------------
+
+(defn pprint-str [& args]
+  ; note that we have to do dynamic lookup here, cljs.pprint is present only in dev mode
+  ; or when explicitly required by the user of cljs-devtools
+  (if (exists? js/devtools.optional.pprint)
+    (with-out-str
+      (binding [*print-level* 300]
+        (apply js/devtools.optional.pprint args)))
+    (apply pr-str args)))
+
 ; -- version helpers --------------------------------------------------------------------------------------------------------
 
 (defn ^:dynamic make-version-info []
@@ -87,9 +100,9 @@
 
 (defn print-config-overrides-if-requested! [msg]
   (when (prefs/pref :print-config-overrides)
-    (let [diff (second (data/diff defaults/prefs (prefs/get-prefs)))]
+    (let [diff (second (data/diff @prefs/default-config (prefs/get-prefs)))]
       (if-not (empty? diff)
-        (.info js/console msg (with-out-str (pprint diff)))))))
+        (.info js/console msg (pprint-str diff))))))
 
 ; -- custom formatters detection --------------------------------------------------------------------------------------------
 

test/src/tests/devtools/tests/prefs.cljs

@@ -6,12 +6,13 @@
             [devtools.prefs :refer [merge-prefs! set-pref! set-prefs! update-pref! get-prefs pref]]))
 
 (deftest test-default-prefs
-  (testing "default prefs should exist"
-    (is (> (count defaults/prefs) 0)))
-  (testing "some known default prefs values"
-    (is (= (:span defaults/prefs) "span"))
-    (is (= (:ol defaults/prefs) "ol"))
-    (is (= (:li defaults/prefs) "li"))))
+  (let [default-config @defaults/config]
+    (testing "default prefs should exist"
+      (is (> (count default-config) 0)))
+    (testing "some known default prefs values"
+      (is (= (:span default-config) "span"))
+      (is (= (:ol default-config) "ol"))
+      (is (= (:li default-config) "li")))))
 
 (deftest test-changing-prefs
   (testing "set prefs"

test/src/tests/devtools/tests/utils/test.cljs

@@ -12,7 +12,7 @@
             [clojure.string :as string]))
 
 (defn reset-prefs-to-defaults! []
-  (set-prefs! defaults/prefs))
+  (set-prefs! @defaults/config))
 
 ; taken from https://github.com/purnam/purnam/blob/62bec5207621779a31c5adf3593530268aebb7fd/src/purnam/native/functions.cljs#L128-L145
 ; Copyright © 2014 Chris Zheng