Variables aren't expanded in path:-style dependencies

[ryandesign (Ryan Carsten Schmidt)]

path:-style dependencies don't work as documented. The ​documentation shows this example:

depends_run         path:${prefix}/lib/libltdl.a:libtool

It turns out MacPorts doesn't actually expand variables here, so this doesn't work as intended.

Furthermore, it turns out MacPorts actually prepends "${prefix}/" if the given path does not begin with a slash.

So,

1) the Guide should show and recommend this simpler way to specify a dependency if it is in ${prefix}:

depends_run         path:lib/libltdl.a:libtool

And it could show a different example using variable expansion in the path, if the path is not in ${prefix} (a file in ${frameworks_dir} perhaps)

2) MacPorts base should be fixed to expand variables so this works as advertised

Ports that define dependencies using "path:${prefix}/..." should use "path:..." instead since this is shorter, simpler, and actually works with MacPorts 1.6.0.

[ryandesign (Ryan Carsten Schmidt)]

Changed all my ports to the new style in r41807.

[ryandesign (Ryan Carsten Schmidt)]

Changed all openmaintainer ports to the new style in r41808.

[ryandesign (Ryan Carsten Schmidt)]

Replying to ryandesign@…:

Changed all openmaintainer ports to the new style in r41808.

Actually r41808 was for all nomaintainer ports. r41809 is for the openmaintainer ports.

[simon@…]

I committed the doc fix in r41866 and r41871. But I didn't add an example for ${frameworks_dir} because I don't know how this works.

By the way, it looks like the guide isn't updated on commit anymore.

Simon

[wsiegrist@…]

I broke guide regeneration at some point, but its fixed. Thanks for catching it for me.

[blb@…]

Replying to ryandesign@…:

And it could show a different example using variable expansion in the path, if the path is not in ${prefix} (a file in ${frameworks_dir} perhaps)

Note that frameworks_dir is in ${prefix} (at least by default, unless --with-frameworks-dir is used with configure). Once variable expansion works, then the example could be

path:${frameworks_dir}/MacPorts.framework/Versions/A/MacPorts:MacPorts_Framework

[ryandesign (Ryan Carsten Schmidt)]

Replying to jmr@...:

The problem with upgrading autoconf is actually that depspecs are auto-escaped, so variable substitution is not done, so it ends up looking for /opt/local/\${prefix}/bin/perl (because the prefix is prepended to any path that doesn't start with a slash.)

Joshua, could you tell me where in the source this is? I'm having a hard time finding it.

[blb@…]

Replying to ryandesign@…:

Joshua, could you tell me where in the source this is? I'm having a hard time finding it.

I think he's referring to ​proc _pathtest.

[jmroot (Joshua Root)]

This problem only occurs with upgrade, where the depspecs are taken from the PortIndex, and not with install, where they are taken directly from the Portfile. The backslash in \${prefix} is there in the PortIndex, so it looks like the bug is either in the portindex command, or in the way data is loaded from the PortIndex.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Cc Me!

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Based on this discussion, could the problem be the following in portindex?:

--- portindex   2008-11-04 09:06:00.000000000 -0500                                                                                                                                                       
+++ portindex.new       2008-11-21 21:02:26.000000000 -0500                                                                                                                                               
@@ -38,7 +38,7 @@
     incr stats(total)                                                                                                                                                                                    
     global macports::prefix                                                                                                                                                                              
     set save_prefix $prefix                                                                                                                                                                              
-    set prefix {\${prefix}}                                                                                                                                                                              
+    set prefix {${prefix}}                                                                                                                                                                               
     if {[catch {set interp [mportopen file://[file join $directory $portdir]]} result]} {                                                                                                                
         puts stderr "Failed to parse file $portdir/Portfile: $result"                                                                                                                                    
         # revert the prefix.       

Making the change seems to have changed the \${prefix} to ${prefix} in a test Portindex file.

[ryandesign (Ryan Carsten Schmidt)]

Replying to mcalhoun@…:

Making the change seems to have changed the \${prefix} to ${prefix} in a test Portindex file.

But then you're just setting ${prefix} to itself. Why is there code that goes to the trouble of saving the prefix, setting it to a backslashed version of the prefix, and restoring it later? That code was added in r14567. We would first need to fully understand why it was added then, to understand whether we can safely remove it now. Cc'ing Paul, who committed that revision.

[ryandesign (Ryan Carsten Schmidt)]

Replying to ryandesign@…:

That code was added in r14567.

Actually it looks like it was added in r14532, bugfixed in r14545 and refined in r14567.

Paul, do you remember the motivation for and implication of this change?

[jmroot (Joshua Root)]

I assume it's that way because the PortIndex is usually not generated on the local machine, so the prefix could be different.

[blb@…]

Replying to jmr@…:

I assume it's that way because the PortIndex is usually not generated on the local machine, so the prefix could be different.

I ​believe that was exactly the reason.

[pguyot (Paul Guyot)]

It looks like quite a dirty hack.... I believe it was indeed done to cope with PortIndex generation.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Please correct me if I am wrong, but it seems that the situation is:

• portindex ​reads the Portfile for dependencies.
• /opt/local should not be in the Portindex, so portindex MIGHT try

  set prefix {${prefix}}
  

before reading, which would result in ${prefix} in Portindex (instead of /opt/local).

• Unfortunately, when Portindex is read, ${prefix} is evaluated to an empty string in ​mportsearch.
• So what portindex ​actually does results in \${prefix} in Portindex.
• Unfortunately, when the procedure ​_pathtest is finally called, the argument depspec still contains \${prefix}, which is never evaluated.
• Therefore, _pathtest not only ​prepends the actual prefix, but, even if it didn't, would not work correctly because ​_mportsearchpath is searching for something with \${prefix} in it.

My Tcl is limited, so I do not know why

set line [read $fd $len]

behaves the way it does if $fd contains ${prefix} (not \${prefix}).

I tried a couple of things (like using eval) to have ${prefix} be evaluated in _pathtest, but all I could manage was to have an empty string for ${prefix}.

[jmroot (Joshua Root)]

I think the command you want is subst. But I don't know why you'd be getting an empty string and not an error.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Replying to jmr@…:

I think the command you want is subst. But I don't know why you'd be getting an empty string and not an error.

I was not able to get subst to work.
Attached is a first attempt to correct the problem.
I know it's not pretty, but it was the only thing I could get to work.

The x11prefix (and eventually frameworks_dir and applications_dir) won't do anything without a modification to portindex.

[tobypeterson]

Milestone MacPorts base bugs deleted

[jmroot (Joshua Root)]

I think this may have been fixed "accidentally" by r44362, since it now grabs the portinfo from the portfile instead of using what's in the index. Will need to re-"break" a port and regenerate the index to test that theory, though.

[jmroot (Joshua Root)]

Did the testing, looks fixed.

[neverpanic (Clemens Lang)]

In 9a23db2/macports-base:

portindex: Restore special $prefix handling

This avoids expanded values for ${prefix} in the PortIndex.

Closes: #53169
See: #17182