Merge pull request #136 from ehudhala/feature/print_actual_args_even_…

…when_source_unavailable

We want to still print the given args even when the source is unavaii…

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         include:

icecream/icecream.py

@@ -17,6 +17,7 @@
 import inspect
 import pprint
 import sys
+import warnings
 from datetime import datetime
 import functools
 from contextlib import contextmanager
@@ -37,8 +38,8 @@
 
 PYTHON2 = (sys.version_info[0] == 2)
 
-
 _absent = object()
+_arg_source_missing = object()
 
 
 def bindStaticVariable(name, value):
@@ -90,25 +91,25 @@ def colorizedStderrPrint(s):
 DEFAULT_ARG_TO_STRING_FUNCTION = pprint.pformat
 
 
-class NoSourceAvailableError(OSError):
-    """
-    Raised when icecream fails to find or access source code that's
-    required to parse and analyze. This can happen, for example, when
+"""
+This info message is printed instead of the arguments when icecream
+fails to find or access source code that's required to parse and analyze.
+This can happen, for example, when
 
-      - ic() is invoked inside a REPL or interactive shell, e.g. from the
-        command line (CLI) or with python -i.
+  - ic() is invoked inside a REPL or interactive shell, e.g. from the
+    command line (CLI) or with python -i.
 
-      - The source code is mangled and/or packaged, e.g. with a project
-        freezer like PyInstaller.
+  - The source code is mangled and/or packaged, e.g. with a project
+    freezer like PyInstaller.
 
-      - The underlying source code changed during execution. See
-        https://stackoverflow.com/a/33175832.
-    """
-    infoMessage = (
-        'Failed to access the underlying source code for analysis. Was ic() '
-        'invoked in a REPL (e.g. from the command line), a frozen application '
-        '(e.g. packaged with PyInstaller), or did the underlying source code '
-        'change during execution?')
+  - The underlying source code changed during execution. See
+    https://stackoverflow.com/a/33175832.
+"""
+NO_SOURCE_AVAILABLE_WARNING_MESSAGE = (
+    'Failed to access the underlying source code for analysis. Was ic() '
+    'invoked in a REPL (e.g. from the command line), a frozen application '
+    '(e.g. packaged with PyInstaller), or did the underlying source code '
+    'change during execution?')
 
 
 def callOrValue(obj):
@@ -143,8 +144,12 @@ def indented_lines(prefix, string):
 
 
 def format_pair(prefix, arg, value):
-    arg_lines = indented_lines(prefix, arg)
-    value_prefix = arg_lines[-1] + ': '
+    if arg is _arg_source_missing:
+        arg_lines = []
+        value_prefix = prefix
+    else:
+        arg_lines = indented_lines(prefix, arg)
+        value_prefix = arg_lines[-1] + ': '
 
     looksLikeAString = value[0] + value[-1] in ["''", '""']
     if looksLikeAString:  # Align the start of multiline strings.
@@ -204,12 +209,7 @@ def __init__(self, prefix=DEFAULT_PREFIX,
     def __call__(self, *args):
         if self.enabled:
             callFrame = inspect.currentframe().f_back
-            try:
-                out = self._format(callFrame, *args)
-            except NoSourceAvailableError as err:
-                prefix = callOrValue(self.prefix)
-                out = prefix + 'Error: ' + err.infoMessage
-            self.outputFunction(out)
+            self.outputFunction(self._format(callFrame, *args))
 
         if not args:  # E.g. ic().
             passthrough = None
@@ -228,27 +228,29 @@ def format(self, *args):
     def _format(self, callFrame, *args):
         prefix = callOrValue(self.prefix)
 
-        callNode = Source.executing(callFrame).node
-        if callNode is None:
-            raise NoSourceAvailableError()
-
-        context = self._formatContext(callFrame, callNode)
+        context = self._formatContext(callFrame)
         if not args:
             time = self._formatTime()
             out = prefix + context + time
         else:
             if not self.includeContext:
                 context = ''
             out = self._formatArgs(
-                callFrame, callNode, prefix, context, args)
+                callFrame, prefix, context, args)
 
         return out
 
-    def _formatArgs(self, callFrame, callNode, prefix, context, args):
-        source = Source.for_frame(callFrame)
-        sanitizedArgStrs = [
-            source.get_text_with_indentation(arg)
-            for arg in callNode.args]
+    def _formatArgs(self, callFrame, prefix, context, args):
+        callNode = Source.executing(callFrame).node
+        if callNode is not None:
+            source = Source.for_frame(callFrame)
+            sanitizedArgStrs = [
+                source.get_text_with_indentation(arg)
+                for arg in callNode.args]
+        else:
+            warnings.warn(NO_SOURCE_AVAILABLE_WARNING_MESSAGE,
+                          category=RuntimeWarning, stacklevel=4)
+            sanitizedArgStrs = [_arg_source_missing] * len(args)
 
         pairs = list(zip(sanitizedArgStrs, args))
 
@@ -271,8 +273,12 @@ def argPrefix(arg):
         #
         #   ic| "hello": 'hello'.
         #
+        # When the source for an arg is missing we also only print the value,
+        # since we can't know anything about the argument itself.
         pairStrs = [
-            val if isLiteral(arg) else (argPrefix(arg) + val)
+            val
+            if (isLiteral(arg) or arg is _arg_source_missing)
+            else (argPrefix(arg) + val)
             for arg, val in pairs]
 
         allArgsOnOneLine = self._pairDelimiter.join(pairStrs)
@@ -313,9 +319,8 @@ def argPrefix(arg):
 
         return '\n'.join(lines)
 
-    def _formatContext(self, callFrame, callNode):
-        filename, lineNumber, parentFunction = self._getContext(
-            callFrame, callNode)
+    def _formatContext(self, callFrame):
+        filename, lineNumber, parentFunction = self._getContext(callFrame)
 
         if parentFunction != '<module>':
             parentFunction = '%s()' % parentFunction
@@ -328,9 +333,9 @@ def _formatTime(self):
         formatted = now.strftime('%H:%M:%S.%f')[:-3]
         return ' at %s' % formatted
 
-    def _getContext(self, callFrame, callNode):
-        lineNumber = callNode.lineno
+    def _getContext(self, callFrame):
         frameInfo = inspect.getframeinfo(callFrame)
+        lineNumber = frameInfo.lineno
         parentFunction = frameInfo.function
 
         filepath = (realpath if self.contextAbsPath else basename)(frameInfo.filename)

tests/test_icecream.py

@@ -13,6 +13,8 @@
 import functools
 import sys
 import unittest
+import warnings
+
 try:  # Python 2.x.
     from StringIO import StringIO
 except ImportError:  # Python 3.x.
@@ -21,8 +23,7 @@
 from os.path import basename, splitext, realpath
 
 import icecream
-from icecream import ic, argumentToString, stderrPrint, NoSourceAvailableError
-
+from icecream import ic, argumentToString, stderrPrint, NO_SOURCE_AVAILABLE_WARNING_MESSAGE
 
 TEST_PAIR_DELIMITER = '| '
 MY_FILENAME = basename(__file__)
@@ -183,12 +184,13 @@ def parseOutputIntoPairs(out, err, assertNumLines,
         if len(pairs[0]) == 1 and line.startswith(' '):
             arg, value = linePairs[-1][-1]
             looksLikeAString = value[0] in ["'", '"']
-            prefix = (arg + ': ') + (' ' if looksLikeAString else '')
+            prefix = ((arg + ': ' if arg is not None else '')  # A multiline value
+                      + (' ' if looksLikeAString else ''))
             dedented = line[len(ic.prefix) + len(prefix):]
             linePairs[-1][-1] = (arg, value + '\n' + dedented)
         else:
             items = [
-                (p[0].strip(), None) if len(p) == 1  # A value, like ic(3).
+                (None, p[0].strip()) if len(p) == 1  # A value, like ic(3).
                 else (p[0].strip(), p[1].strip())  # A variable, like ic(a).
                 for p in pairs]
             linePairs.append(items)
@@ -251,7 +253,7 @@ def testNestedMultiline(self):
             ic(a,
                'foo')
         pairs = parseOutputIntoPairs(out, err, 1)[0]
-        assert pairs == [('a',  '1'), ("'foo'", None)]
+        assert pairs == [('a',  '1'), (None, "'foo'")]
 
         with disableColoring(), captureStandardStreams() as (out, err):
             noop(noop(noop({1: ic(
@@ -478,7 +480,7 @@ def testValues(self):
             ic(3, 'asdf', "asdf")
 
         pairs = parseOutputIntoPairs(out, err, 1)
-        assert pairs == [[('3', None), ("'asdf'", None), ("'asdf'", None)]]
+        assert pairs == [[(None, '3'), (None, "'asdf'"), (None, "'asdf'")]]
 
     def testIncludeContextMultiLine(self):
         multilineStr = 'line1\nline2'
@@ -527,10 +529,33 @@ def testMultilineInvocationWithComments(self):
         pairs = parseOutputIntoPairs(out, err, 1)[0]
         assert pairs == [('a', '1'), ('b', '2')]
 
-    def testNoSourceAvailable(self):
-        with disableColoring(), captureStandardStreams() as (out, err):
-            eval('ic()')
-        assert NoSourceAvailableError.infoMessage in err.getvalue()
+    def testNoSourceAvailablePrintsValues(self):
+        with disableColoring(), captureStandardStreams() as (out, err), warnings.catch_warnings():
+            # we ignore the warning so that it doesn't interfere with parsing ic's output
+            warnings.simplefilter("ignore")
+            eval('ic(a, b)')
+            pairs = parseOutputIntoPairs(out, err, 1)
+            self.assertEqual(pairs, [[(None, '1'), (None, "2")]])
+
+    def testNoSourceAvailablePrintsMultiline(self):
+        """
+        This tests for a bug which caused only multiline prints to fail.
+        """
+        multilineStr = 'line1\nline2'
+        with disableColoring(), captureStandardStreams() as (out, err), warnings.catch_warnings():
+            # we ignore the warning so that it doesn't interfere with parsing ic's output
+            warnings.simplefilter("ignore")
+            eval('ic(multilineStr)')
+            pair = parseOutputIntoPairs(out, err, 2)[0][0]
+            self.assertEqual(pair, (None, ic.argToStringFunction(multilineStr)))
+
+    def testNoSourceAvailableIssuesExactlyOneWarning(self):
+        with warnings.catch_warnings(record=True) as all_warnings:
+            eval('ic(a)')
+            eval('ic(b)')
+            assert len(all_warnings) == 1
+            warning = all_warnings[-1]
+            assert NO_SOURCE_AVAILABLE_WARNING_MESSAGE in str(warning.message)
 
     def testSingleTupleArgument(self):
         with disableColoring(), captureStandardStreams() as (out, err):