import-checker: don't treat modules as relative one if not found The previous patch ensures all module names are recorded in `imports` as absolute names, so we no longer need to treat modules as ones imported relatively from the target source if they appear to not be from the stdlib.

import-checker: make imported_modules yield absolute dotted_name_of_path This patch makes `imported_modules()` always yield absolute `dotted_name_of_path()`-ed name by strict detection with `fromlocal()`. This change improves circular detection in some points: - locally defined modules, of which name collides against one of standard library, can be examined correctly For example, circular import related to `commands` is overlooked before this patch. - names not useful for circular detection are ignored Names below are also yielded before this patch: - module names of standard library (= not locally defined one) - non-module names (e.g. `node.nullid` of `from node import nullid`) These redundant names decrease performance of circular detection. For example, with files at 1ef96a3b8b89, average loops per file in `checkmod()` is reduced from 165 to 109. - `__init__` can be handled correctly in `checkmod()` For example, current implementation has problems below: - `from xxx import yyy` doesn't recognize `xxx.__init__` as imported - `xxx.__init__` imported via `import xxx` is treated as `xxx`, and circular detection is aborted, because `key` of such module name is not `xxx` but `xxx.__init__` - it is easy to enhance for `from . import xxx` style or so (in the future) Module name detection in `imported_modules()` can use information in `ast.ImportFrom` fully. It is assumed that all locally defined modules are correctly specified to `import-checker.py` at once. Strictly speaking, when `from foo.bar.baz import module1` imports `foo.bar.baz.module1` module, current `imported_modules()` yields only `foo.bar.baz.__init__`, even though also `foo.__init__` and `foo.bar.__init__` should be yielded to detect circular import exactly. But this limitation is reasonable one for improvement in this patch, because current `__init__` files in Mercurial seems to be implemented carefully.

import-checker: add utility to examine what module is imported easily `fromlocalfunc()` uses: - `modulename` (of the target source) to compose absolute module name imported relatively from it It is assumed that `modulename` is an `dotted_name_of_path()`-ed source file, which may have `.__init__` at the end of it. This assumption makes composing `prefix` of relative name easy. - `localmods` to examine whether there is a locally defined (= Mercurial specific) module matching against the specified name It is assumed that module names not existing in `localmods` are ones of Python standard library.

subrepo: further replacement of try/except with 'next' Burn StopIteration, Burn!

parsers: use 'next' instead of try/except This get rid of another StopIteration abomination. The change in self.current value is supposed to not matter as nobody should be calling '_advance' after that (as per Matt wisdom).

dagparser: use 'next' instead of try/except for default value "Ich liebe es wenn ein Plan funktioniert."

getlogrevs: rewrite a loop to get read of try/except Get rid of the 'except StopIteration' abomination.

_makelogrevset: replace try/except with 'next' usage More readable without the 'except StopIteration' abomination.

ignore: move readpatternfile to match.py In preparation for adding 'include:' rule support to match.py, let's move the pattern file reader function to match.py

ignore: rename readignorefile to readpatternfile A future commit will move the readignorefile logic into match.py so it can be used from general match rules. Let's rename the function to represent this new behavior.

ignore: combine readignorefile and _ignorefile _ignorefile did nothing except open the file. Let's combine it with readignorefile for simplicity. This will make it easier to rename and move to match.py in upcoming patches.

ignore: move bad file handling out of readignorefile In preparation for moving readignorefile to match.py to make it more generally usable, let's move the bad ignore file handling up to the ignore specific logic.