histedit: add clear method to remove state Encapsulate the unlinking histedit-state and use the vfs layer instead of os.unlink.

histedit: use state object where necessary We are using the properties from the state object where necessary and ensure that the state is set correctly.

histedit: add histedit state class Add an histeditstate class that is intended to hold the current state. This allows us encapsulate the state and avoids passing around a tuple which is based on the serialization format. In particular this will give actions more control over the state and allow external sources to have more control of histedits behavior, e.g. an external implementation of x/exec.

import-checker: check modules for pure Python build correctly Before this patch, "import-checker.py" just replaces "/" in specified filenames by ".". This makes modules for pure Python build belong to "mercurial.pure" package, and prevents "import-checker.py" from correctly checking about cyclic dependency in them. This patch discards "pure" component from fully qualified name of such modules. To avoid discarding "pure" from the module name of standard libraries unexpectedly, this patch allows "dotted_name_of_path" to discard "pure" only from Mercurial specific modules, which are specified via command line arguments.

import-checker: treat "from mercurial import XXXX" style correctly Before this patch, "import-checker.py" assumes that the name of Mercurial module recognized by "imported_modules" doesn't have package part: for example, "util". This is reason why "import-checker.py" always builds fully qualified module name up relatively, if the given module doesn't belong to standard Python library. But in fact, modules imported in "from mercurial import XXXX" style already have fully qualified name: for example, "mercurial.util" module imported by "mercurial.parsers" is treated as "mercurial.mercurial.util" because of building module name up relatively. This prevents "import-checker.py" from correctly checking about cyclic dependency in them. This patch avoids building module name up relatively, also if module name starts with "mercurial.", to treat modules imported in "from mercurial import XXXX" style correctly.

encoding: avoid cyclic dependency around "parsers" in pure Python build 80f2b63dd83a brought "asciilower" and "import parsers" into "encoding.py". This works fine with "parsers" module in C implementation, but doesn't with one in pure Python implementation, because the latter causes cyclic dependency below and aborting execution: util => i18n => encoding => parsers => util This patch delays importing "parsers" module until it is really needed, to avoid cyclic dependency around "parsers" in pure Python build.