[wix-devs] WIXBUG3704 - Allow access to persisted variables from related bundles

Wed May 5 12:34:46 PDT 2021

If there is a valid means of substitution in this context, whether it be 
from environment variables or other sources
available to the engine, the result of the expansion could reasonably be 
expected to be a function the bundle for
which the expansion is being done. Otherwise, I would think that all 
expansions would be done in the context
of the "owning bundle" and the formatted strings would effectively 
become ordinary strings.

Any distinction that is required can be handled by either of the two 
schemes we've been discussing (and others).

I  think that, in some sense, formatted strings need to be self aware 
substrings of ordinary strings that might be
expanded if they were formatted strings should not be expanded based on 
this content. Any type coercion that
might be performed based on the type requested being different from the 
stored type should take this into account.
If formatted strings can be requested and available, they should not be 
expanded. (I assume that, in this case,
the train has already left the station and that there is no place 
further down the line to do the expansion, so this
case is moot.) In the other direction, variables stored as formatted 
strings can be expanded to ordinary strings
before converting to other types. The remaining types can be converted 
directly when it makes sense or they can
be converted to strings and then to their requested types. It is in this 
last group of conversions that I would expect
the most conversion errors to be detected.

Is the purpose of a "none" value to replace an ordinary value when you 
wish to essentially undefine it? What
advantage does this yield over actually undefining the value? My 
understanding of "ifdef" in other Wix
contexts is that zero and null are the only values that are considered 
undefined.

Bottom line somebody needs to make a call so you can get your work done. 
I never meant to tie you up, but I
do think that this topic has needed some discussion so that the next 
time it comes up, the reasons for our choices
will be on the record.

Ron

On 5/5/2021 1:56 PM, Hoover, Jacob wrote:
>
> Was hoping Sean would respond on this…  It is my understanding that 
> the formatted string is expanded at runtime by the engine, when a 
> variable is evaluated.
>
> There is concern that a string variable which is restored as 
> formatted, that it could get variable expansion that it would not 
> have, Also if a variable was formatted but is restored as a string 
> that it would no longer get expansion.
>
> *From:* wix-devs <wix-devs-bounces at lists.wixtoolset.org> *On Behalf Of 
> *Ron Martin via wix-devs
> *Sent:* Tuesday, May 4, 2021 2:42 PM
> *To:* Bob Arnson <bob at firegiant.com>; WiX Toolset Developer Mailing 
> List <wix-devs at lists.wixtoolset.org>
> *Cc:* Ron Martin <cpuwzd at comcast.net>
> *Subject:* Re: [wix-devs] WIXBUG3704 - Allow access to persisted 
> variables from related bundles
>
> In what context is BURN_VARIANT_TYPE_FORMATTED expanded? Would it be
> stored in one context and
> interpreted in another? What can change in the context between creation
> and use?
>
> I'm just trying to get my head around the real issues.
>
> Ron
>
> On 5/4/2021 3:17 PM, Bob Arnson wrote:
> > BAs already have to specify a type when getting a variable value 
> from the engine. The engine knows a variable's type when it persists 
> the value -- so what if it required a variable to exist so it had the 
> type when reading it? At that point, the registry type could be REG_SZ 
> for everything, no encoding necessary.
> >
> > -----Original Message-----
> > From: wix-devs <wix-devs-bounces at lists.wixtoolset.org 
> <mailto:wix-devs-bounces at lists.wixtoolset.org>> On Behalf Of Rob 
> Mensching via wix-devs
> > Sent: Tuesday, 4 May, 2021 14:13
> > To: WiX Toolset Developer Mailing List 
> <wix-devs at lists.wixtoolset.org 
> <mailto:wix-devs at lists.wixtoolset.org>>; Ron Martin 
> <cpuwzd at comcast.net <mailto:cpuwzd at comcast.net>>
> > Cc: Rob Mensching <rob at firegiant.com <mailto:rob at firegiant.com>>
> > Subject: Re: [wix-devs] WIXBUG3704 - Allow access to persisted 
> variables from related bundles
> >
> > Sorry, I mentioned encoding the values in a string the way the 
> Windows Installer does in the Registry table to include it as an 
> option. I do not have a strong opinion that it is the best way to go 
> (although encoding in JSON or XML seems way overkill). Trying to reuse 
> the built-in registry types is noble if you can resolve all the issues 
> Sean was discussing.
> >
> > -----Original Message-----
> > From: wix-devs <wix-devs-bounces at lists.wixtoolset.org 
> <mailto:wix-devs-bounces at lists.wixtoolset.org>> On Behalf Of Hoover, 
> Jacob via wix-devs
> > Sent: Tuesday, May 4, 2021 10:02 AM
> > To: Ron Martin <cpuwzd at comcast.net <mailto:cpuwzd at comcast.net>>; 
> wix-devs <wix-devs at lists.wixtoolset.org 
> <mailto:wix-devs at lists.wixtoolset.org>>
> > Cc: Hoover, Jacob <Jacob.Hoover at greenheck.com 
> <mailto:Jacob.Hoover at greenheck.com>>
> > Subject: Re: [wix-devs] WIXBUG3704 - Allow access to persisted 
> variables from related bundles
> >
> > Unrecognized types? The engine only supports a fixed set of types. 
> Extensions can’t define additional variable types.
> >
> > “Much easier” is an opinion.
> >
> > If we really want to go the string route, why not use a JSON object 
> in the registry? We could then define it’s type and value, still live 
> as a string, and have a well defined structure to validate against.
> >
> > From: Ron Martin <cpuwzd at comcast.net <mailto:cpuwzd at comcast.net>>
> > Sent: Tuesday, May 4, 2021 11:51 AM
> > To: Hoover, Jacob <Jacob.Hoover at greenheck.com 
> <mailto:Jacob.Hoover at greenheck.com>>; wix-devs 
> <wix-devs at lists.wixtoolset.org <mailto:wix-devs at lists.wixtoolset.org>>
> > Subject: Re: [wix-devs] WIXBUG3704 - Allow access to persisted 
> variables from related bundles
> >
> >
> > Some of the things I thought about before making my suggestion:
> >
> > If all of the strings we store in the registry (in this context) are 
> differentiated by their first character, many new types can be added 
> later if necessary. A single switch statement can be used to separate 
> the type. Unrecognized types can be passed through extensions.
> >
> > The registry was not designed for flexibility or extensibility. 
> Binary data can be organized for straight-forward decoding, just as 
> string data, but for debugging purposes, it is much easier to decode 
> strings than raw binary representation of multiple data structures.
> >
> > Registry strings should not be used to store binary data in its raw 
> form because there is a potential for truncation when a null character 
> is encountered. Registry strings are constrained to UTF-16 with no 
> encoding prefix.
> >
> > Ron
> > On 5/4/2021 11:27 AM, Hoover, Jacob wrote:
> > easier to handle.
> >
> > From: wix-devs <wix-devs-bounces at lists.wixtoolset.org 
> <mailto:wix-devs-bounces at lists.wixtoolset.org>><mailto:wix-devs-bounces at lists.wixtoolset.org 
> <mailto:wix-devs-bounces at lists.wixtoolset.org>> On Behalf Of Ron 
> Martin via wix-devs
> > Sent: Friday, April 30, 2021 2:49 PM
> > To: 
> wix-devs at lists.wixtoolset.org<mailto:wix-devs at lists.wixtoolset.org 
> <mailto:wix-devs at lists.wixtoolset.org%3cmailto:wix-devs at lists.wixtoolset.org>>
> > Cc: Ron Martin <cpuwzd at comcast.net 
> <mailto:cpuwzd at comcast.net>><mailto:cpuwzd at comcast.net 
> <mailto:cpuwzd at comcast.net>>
> > Subject: Re: [wix-devs] WIXBUG3704 - Allow access to persisted 
> variables from related bundles
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