py3: finish porting iteritems() to pycompat and remove source transformer This commit finishes porting .iteritems() to pycompat.iteritems() for the mercurial package. The translation of .iteritems() to .items() was the last conversion performed by the source transformer. With the porting to pycompat complete, we no longer have a need for the source transformer. So the source transformer has been removed. Good riddance! The code base is now compatible with Python 2 and Python 3. For the record, as the person who introduced the source transformer, it brings me joy to delete it. It accomplished its goal to facilitate a port to Python 3 without overly burdening people on some painful low-level differences between Python 2 and 3. It is unfortunate we still have to wallpaper over many differences with the pycompat shim. But it is what it is. Differential Revision: https://phab.mercurial-scm.org/D7015

py3: define and use pycompat.iteritems() for hgext/ .iteritems() -> .items() is the last source transform being performed. But it is also the most widely used. This commit adds a pycompat.iteritems symbol and imports it in place of .iteritems() for usage in hgext/. I chose to stop at just hgext/ because the patch will be large and it is an easy boundary to stop at since we can disable source transformation on a per-package basis. There are places where the type does implement items() and we could call items() directly. However, this would require critical thought and I thought it would be easier to just blindly change the code. We know which call sites need to be audited in the future because they have "pycompat.iteritems." With this change, we no longer perform source transformation on hgext! Differential Revision: https://phab.mercurial-scm.org/D7014

py3: define and use pycompat.itervalues() .itervalues() only exists on Python 2. Python 3's equivalent is .values(). But we don't want to blindly use .values() everywhere because on Python 2, it will create a list, which will have performance implications. This commit introduces pycompat.itervalues() which will call the appropriate method on the passed object. We update all callers of obj.itervalues() to pycompat.itervalues(obj) instead. With this commit, the only source tranforming remaining is for iteritems(). Victory is near... Differential Revision: https://phab.mercurial-scm.org/D7013

py3: stop normalizing 2nd argument of *attr() to unicode Now that we don't byteify strings, we can stop normalizing the 2nd string argument to getattr() and remove explicit overrides we were using in the code base. We no longer use some helper functions in the source transformer, so we remove those as well. Differential Revision: https://phab.mercurial-scm.org/D7012

log: populate keywords if specified in custom -Tjson(...) or -Tcbor(...) To make things simple, early return for ui.quiet is disabled if the formatter is templated and provides some datahint().

formatter: map -Tjson(...) and -Tcbor(...) to templater Even though custom JSON output could be generated by using --config template.json="{dict(...)|json}" ..., doing that is tedious because of the trailing comma handling. This patch introduces special syntax for JSON/CBOR formats. -Tjson(...) is translated to template as if function-style template definition were supported: [templates] json(...) = "{dict(...)|json}" json(...):docheader = "[\n " json(...):docfooter = "\n]\n" json(...):separator = ",\n "