Improved localization testing.

Moved localization tests to tools/hacking.py.

Change-Id: I903b90dfb09a46a72b1c64c30301f90661999f5b

tools/hacking.py

@@ -25,6 +25,8 @@ import inspect
 import os
 import re
 import sys
+import tokenize
+import traceback
 
 import pep8
 
@@ -35,6 +37,7 @@ import pep8
 #N4xx docstrings
 #N5xx dictionaries/lists
 #N6xx Calling methods
+#N7xx localization
 
 IMPORT_EXCEPTIONS = ['sqlalchemy', 'migrate', 'nova.db.sqlalchemy.session']
 
@@ -167,6 +170,94 @@ def nova_import_module_only(logical_line):
 
     # TODO(jogo) handle "from x import *"
 
+
+FORMAT_RE = re.compile("%(?:"
+                            "%|"           # Ignore plain percents
+                            "(\(\w+\))?"   # mapping key
+                            "([#0 +-]?"    # flag
+                             "(?:\d+|\*)?"  # width
+                             "(?:\.\d+)?"   # precision
+                             "[hlL]?"       # length mod
+                             "\w))")        # type
+
+
+class LocalizationError(Exception):
+    pass
+
+
+def check_l18n():
+    """Generator that checks token stream for localization errors.
+
+    Expects tokens to be ``send``ed one by one.
+    Raises LocalizationError if some error is found.
+    """
+    while True:
+        try:
+            token_type, text, _, _, _ = yield
+        except GeneratorExit:
+            return
+        if token_type == tokenize.NAME and text == "_":
+            while True:
+                token_type, text, start, _, _ = yield
+                if token_type != tokenize.NL:
+                    break
+            if token_type != tokenize.OP or text != "(":
+                continue  # not a localization call
+
+            format_string = ''
+            while True:
+                token_type, text, start, _, _ = yield
+                if token_type == tokenize.STRING:
+                    format_string += eval(text)
+                elif token_type == tokenize.NL:
+                    pass
+                else:
+                    break
+
+            if not format_string:
+                raise LocalizationError(start,
+                    "NOVA N701: Empty localization string")
+            if token_type != tokenize.OP:
+                raise LocalizationError(start,
+                    "NOVA N701: Invalid localization call")
+            if text != ")":
+                if text == "%":
+                    raise LocalizationError(start,
+                        "NOVA N702: Formatting operation should be outside"
+                        " of localization method call")
+                elif text == "+":
+                    raise LocalizationError(start,
+                        "NOVA N702: Use bare string concatenation instead"
+                        " of +")
+                else:
+                    raise LocalizationError(start,
+                        "NOVA N702: Argument to _ must be just a string")
+
+            format_specs = FORMAT_RE.findall(format_string)
+            positional_specs = [(key, spec) for key, spec in format_specs
+                                            if not key and spec]
+            # not spec means %%, key means %(smth)s
+            if len(positional_specs) > 1:
+                raise LocalizationError(start,
+                    "NOVA N703: Multiple positional placeholders")
+
+
+def nova_localization_strings(logical_line, tokens):
+    """Check localization in line.
+
+    N701: bad localization call
+    N702: complex expression instead of string as argument to _()
+    N703: multiple positional placeholders
+    """
+
+    gen = check_l18n()
+    next(gen)
+    try:
+        map(gen.send, tokens)
+        gen.close()
+    except LocalizationError as e:
+        return e.args
+
 #TODO(jogo) Dict and list objects
 
 current_file = ""