Surface internal/userscript JS errors as messages

Configurable via a new content.javascript.log_message setting.
Closes #7173, driven by #7335.

5 files changed, 70 insertions, 4 deletions

diff --git a/doc/changelog.asciidoc b/doc/changelog.asciidoc
index 1a7800dd8..3b5eb2b1d 100644
--- a/doc/changelog.asciidoc
+++ b/doc/changelog.asciidoc
@@ -29,6 +29,9 @@ Added
   prompts (bound to `<Alt+e>` by default).
 - New `clock` value for `statusbar.widgets`, displaying the current time.
 - New `qute://start` built-in start page (not set as the default start page yet).
+- New `content.javascript.log_message` setting, allowing to surface JS log
+  messages as qutebrowser messages (rather than only logging them). By default,
+  errors in internal `qute:` pages and userscripts are shown to the user.
 - New `qute-1pass` userscript using the 1password commandline to fill
   passwords.
 - New features in userscripts:
@@ -87,6 +90,8 @@ Changed
 - Improved output when loading Greasemonkey scripts.
 - The macOS `.app` now is registered as a handler for `.mhtml` files, such as
   the ones produced by `:download --mhtml`.
+- The "... called unimplemented GM_..." messages are now logged as info JS
+  messages instead of errors.
 
 Fixed
 ~~~~~
diff --git a/doc/help/settings.asciidoc b/doc/help/settings.asciidoc
index b16fe2a06..e4eb594b5 100644
--- a/doc/help/settings.asciidoc
+++ b/doc/help/settings.asciidoc
@@ -172,6 +172,7 @@
 |<<content.javascript.clipboard,content.javascript.clipboard>>|Allow JavaScript to read from or write to the clipboard.
 |<<content.javascript.enabled,content.javascript.enabled>>|Enable JavaScript.
 |<<content.javascript.log,content.javascript.log>>|Log levels to use for JavaScript console logging messages.
+|<<content.javascript.log_message,content.javascript.log_message>>|Javascript message sources/levels to show in the qutebrowser UI.
 |<<content.javascript.modal_dialog,content.javascript.modal_dialog>>|Use the standard JavaScript modal dialog for `alert()` and `confirm()`.
 |<<content.javascript.prompt,content.javascript.prompt>>|Show javascript prompts.
 |<<content.local_content_can_access_file_urls,content.local_content_can_access_file_urls>>|Allow locally loaded documents to access other local URLs.
@@ -2400,6 +2401,23 @@ Default:
 - +pass:[unknown]+: +pass:[debug]+
 - +pass:[warning]+: +pass:[debug]+
 
+[[content.javascript.log_message]]
+=== content.javascript.log_message
+Javascript message sources/levels to show in the qutebrowser UI.
+When a JavaScript message is logged from a location matching the glob pattern given in the key, and is from one of the levels listed as value, it's surfaced as a message in the qutebrowser UI.
+By default, errors happening in qutebrowser internally or in userscripts are shown to the user.
+
+Type: <<types,Dict>>
+
+Default: 
+
+- +pass:[qute:*]+:
+
+* +pass:[error]+
+- +pass:[userscript:*]+:
+
+* +pass:[error]+
+
 [[content.javascript.modal_dialog]]
 === content.javascript.modal_dialog
 Use the standard JavaScript modal dialog for `alert()` and `confirm()`.
diff --git a/qutebrowser/browser/shared.py b/qutebrowser/browser/shared.py
index 54c466415..b75f7dab0 100644
--- a/qutebrowser/browser/shared.py
+++ b/qutebrowser/browser/shared.py
@@ -25,6 +25,7 @@ import html
 import enum
 import netrc
 import tempfile
+import fnmatch
 from typing import Callable, Mapping, List, Optional, Iterable, Iterator
 
 from PyQt5.QtCore import QUrl, pyqtBoundSignal
@@ -149,11 +150,30 @@ _JS_LOGMAP: Mapping[str, Callable[[str], None]] = {
     'warning': log.js.warning,
     'error': log.js.error,
 }
+# Callables to use for content.javascript.log_message.
+# Note that the keys are JS log levels here, not config settings!
+_JS_LOGMAP_MESSAGE: Mapping[usertypes.JsLogLevel, Callable[[str], None]] = {
+    usertypes.JsLogLevel.info: message.info,
+    usertypes.JsLogLevel.warning: message.warning,
+    usertypes.JsLogLevel.error: message.error,
+}
 
 
-def javascript_log_message(level, source, line, msg):
+def javascript_log_message(
+    level: usertypes.JsLogLevel,
+    source: str,
+    line: int,
+    msg: str,
+):
     """Display a JavaScript log message."""
-    logstring = "[{}:{}] {}".format(source, line, msg)
+    logstring = f"[{source}:{line}] {msg}"
+
+    for pattern, levels in config.cache['content.javascript.log_message'].items():
+        if level.name in levels and fnmatch.fnmatchcase(source, pattern):
+            func = _JS_LOGMAP_MESSAGE[level]
+            func(f"JS: {logstring}")
+            return
+
     logger = _JS_LOGMAP[config.cache['content.javascript.log'][level.name]]
     logger(logstring)
 
diff --git a/qutebrowser/config/configdata.yml b/qutebrowser/config/configdata.yml
index 4da003b37..220712e2d 100644
--- a/qutebrowser/config/configdata.yml
+++ b/qutebrowser/config/configdata.yml
@@ -940,6 +940,29 @@ content.javascript.log:
     The following levels are valid: `none`, `debug`, `info`, `warning`,
     `error`.
 
+content.javascript.log_message:
+  type:
+    name: Dict
+    keytype: String
+    valtype:
+      name: FlagList
+      valid_values:
+        - info: Show JS info as messages.
+        - warning: Show JS warnings as messages.
+        - error: Show JS errors as messages.
+  default:
+    "qute:*": ["error"]
+    "userscript:*": ["error"]
+  desc: >-
+    Javascript message sources/levels to show in the qutebrowser UI.
+
+    When a JavaScript message is logged from a location matching the glob
+    pattern given in the key, and is from one of the levels listed as value,
+    it's surfaced as a message in the qutebrowser UI.
+
+    By default, errors happening in qutebrowser internally or in userscripts are
+    shown to the user.
+
 content.javascript.modal_dialog:
   type: Bool
   default: false
diff --git a/qutebrowser/javascript/greasemonkey_wrapper.js b/qutebrowser/javascript/greasemonkey_wrapper.js
index ced4e1063..d36328282 100644
--- a/qutebrowser/javascript/greasemonkey_wrapper.js
+++ b/qutebrowser/javascript/greasemonkey_wrapper.js
@@ -129,11 +129,11 @@
     // Stub these two so that the gm4 polyfill script doesn't try to
     // create broken versions as attributes of window.
     function GM_getResourceText(caption, commandFunc, accessKey) {
-        console.error(`${GM_info.script.name} called unimplemented GM_getResourceText`);
+        console.info(`${GM_info.script.name} called unimplemented GM_getResourceText`);
     }
 
     function GM_registerMenuCommand(caption, commandFunc, accessKey) {
-        console.error(`${GM_info.script.name} called unimplemented GM_registerMenuCommand`);
+        console.info(`${GM_info.script.name} called unimplemented GM_registerMenuCommand`);
     }
 
     // Mock the greasemonkey 4.0 async API.