Re: [PATCH 6/7] qapi: Split up scripts/qapi/common.py

[Eric Blake]

On 10/2/19 10:16 AM, Markus Armbruster wrote:
> Eric Blake <address@hidden> writes:
>
> > On 10/1/19 2:15 PM, Markus Armbruster wrote:
> > > The QAPI code generator clocks in at some 3100 SLOC in 8 source files.
> > > Almost 60% of the code is in qapi/common.py.  Split it into more
> > > focused modules:
> > >
> > > * Move QAPISchemaPragma and QAPISourceInfo to qapi/source.py.
> > >
> > > * Move QAPIError and its sub-classes to qapi/error.py.
> > >
> > > * Move QAPISchemaParser and QAPIDoc to parser.py.  Use the opportunity
> > >     to put QAPISchemaParser first.
> > >
> > > * Move check_expr() & friends to qapi/expr.py.  Use the opportunity to
> > >     put the code into a more sensible order.
> >
> > Code motion can be easier to review when it is 1:1 (using 'diff -u
> > <(sed -n '/^-//p' patch) <(sed -n '/^\+//p'patch)', which is quite
> > small if code moved wholesale).  Reordering things breaks that
> > property.
>
> True.  But see below.

> Perhaps a bit of shell wizardry can increase your confidence.
>
> Before this patch:
>
> 1. Split into classes and functions (crudely!):
>
>      $ csplit scripts/qapi/common.py '/^\(class\|def\) /' '{*}'
>
> 2. Rename the parts:
>
>      $ for i in xx*; do n=`sed -n '1s/^[a-z]* \([A-Za-z0-9_]*\).*/\1/p' $i`; [ "$n" ] 
> && mv $i xx-$n; done
>
> 3. Stash them:
>
>      $ mkdir o
>      $ $ mv xx* o
>
> After this patch:
>
> 1. Split:
>
>      $ csplit <(cat 
> scripts/qapi/{common,source,error,parser,expr,schema,gen}.py) '/^\(class\|def\) /' 
> '{*}'
>
> 2. Rename:
>
>      $ for i in xx*; do n=`sed -n '1s/^[a-z]* \([A-Za-z0-9_]*\).*/\1/p' $i`; [ "$n" ] 
> && mv $i xx-$n; done
>
> 3. Stash & diff:
>
>      $ mkdir n
>      $ mv xx* n
>      $ diff -rup o n

Slick.

> Output of diff appended for your reading pleasure.
>
> > Reviewed-by: Eric Blake <address@hidden>
>
> Thanks!
>
>
> diff -rup o/xx-QAPIDoc n/xx-QAPIDoc
> --- o/xx-QAPIDoc        2019-10-02 17:02:35.984552694 +0200
> +++ n/xx-QAPIDoc        2019-10-02 17:06:17.930607336 +0200
> @@ -273,5 +273,31 @@ class QAPIDoc(object):
>                   self.info,
>                   "the following documented members are not in "
>                   "the declaration: %s" % ", ".join(bogus))
> +#
> +# Check (context-free) QAPI schema expression structure
> +#

New boilerplate is obviousl

> +
> +# Names must be letters, numbers, -, and _.  They must start with letter,
> +# except for downstream extensions which must start with __RFQDN_.
> +# Dots are only valid in the downstream extension prefix.
> +valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
> +                        '[a-zA-Z][a-zA-Z0-9_-]*$')
>   

The crude split shows that this blurb changed in relation to which 
class/def it was closest to (but you did say it was a crude split), 
which isn't fatal.

>   
> diff -rup o/xx-QAPIGen n/xx-QAPIGen
> --- o/xx-QAPIGen        2019-10-02 17:02:35.987552655 +0200
> +++ n/xx-QAPIGen        2019-10-02 17:06:17.932607309 +0200
> @@ -43,4 +43,3 @@ class QAPIGen(object):
>           f.close()
>   
>   
> -@contextmanager
> diff -rup o/xx-QAPIGenH n/xx-QAPIGenH
> --- o/xx-QAPIGenH       2019-10-02 17:02:35.987552655 +0200
> +++ n/xx-QAPIGenH       2019-10-02 17:06:17.933607296 +0200
> @@ -7,3 +7,4 @@ class QAPIGenH(QAPIGenC):
>           return guardend(self.fname)
>   
>   
> +@contextmanager

Another victim of the crude split (this line logically begins with the 
next line in the original file(s), not the previous class/def).

> diff -rup o/xx-QAPISchema n/xx-QAPISchema
> --- o/xx-QAPISchema     2019-10-02 17:02:35.986552668 +0200
> +++ n/xx-QAPISchema     2019-10-02 17:06:17.932607309 +0200
> @@ -297,9 +297,26 @@ class QAPISchema(object):
>                       visitor.visit_module(module)
>                   entity.visit(visitor)
>           visitor.visit_end()
> -
> -
>   #
> -# Code generation helpers
> +# QAPI code generation
> +#

More whitespace and boilerplate.


> +++ n/xx-QAPISchemaParser       2019-10-02 17:06:17.930607336 +0200
> @@ -268,14 +268,3 @@ class QAPISchemaParser(object):
>           raise QAPIParseError(self, "documentation comment must end with '##'")
>   
>   
> -#
> -# Check (context-free) schema expression structure
> -#
> -
> -# Names must be letters, numbers, -, and _.  They must start with letter,
> -# except for downstream extensions which must start with __RFQDN_.
> -# Dots are only valid in the downstream extension prefix.
> -valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
> -                        '[a-zA-Z][a-zA-Z0-9_-]*$')
> -
> -

We already visited this above.


>   
> Only in o: xx-camel_case

Interesting change, but not detrimental.

Overall, the interdiff is fairly representative of clean code motion in 
spite of any reordering.  Thanks for doing that!

R-b still stands.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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