Commit graph

12 commits

Author SHA1 Message Date
Alexander Ried 10728c25b0 replaceDependency: fix syntax error 2016-10-28 01:00:04 +02:00
Eelco Dolstra 21a2f2ba3b nix: Add a "dev" output
This gets rid of boehm-dev in the closure (as well as Nix's own
headers).
2016-04-18 21:13:18 +02:00
Russell O'Connor fb683211dc replace-dependency.nix: Remove unnecessary carriage return. 2015-11-16 17:52:12 -05:00
Russell O'Connor 94e68bf9ee replace-dependency.nix: Give attr a slightly more meaningful name of drvHash 2015-11-16 17:44:03 -05:00
Shea Levy afaf712ee7 replace-dependency.nix: Use dynamic attrs now. 2015-11-16 05:42:27 -05:00
Russell O'Connor 782cfe94b0 replace-dependency.nix: new feature
When replace-dependency is given a drv that doesn't actually depend on oldDependency, then just return back the original drv but also issue a warning.
2015-11-15 19:52:30 -05:00
Russell O'Connor 94c6af494a Exponentially reduce computation time needed for replace-dependency by using memoization.
This patch makes two changes.

(1) It memoizes the computation of dependsOnOld.
(2) It replaces rewrittenDerivations with a similar memoized table rewriteMemo.

This prevents the entire tree of run-time dependencies from being traversed and instead only traverses the graph of run-time dependencies.
In the case of deep dependency changes (such as changing one's bash version for an entire NixOS system) this can lead to an exponential speedup in processing time
because shared dependencies are no longer traversed multiple times.

This patch isn't quite derivation-per-derivation equivalent to the original computation.
There are two immaterial differences.

(1) The previous version would always call upon sed to replace oldDependency with newDependency even when the store object being updated doesn't directly depend on
oldDependency.
The new version only replaceds oldDependency with newDependency when the store object being updated actually directly depends on oldDependency (which means there is
actually a hash to replace).
(2) The previous version would list the old store object as a source input of the new store object, *except* for the root derivation being updated.  Because the
root derivation being updated has its actual derivation avaiable the previous verions would make the updated root derivation depend on the old derivation as a
derivation input instead of a source input.
The new version always lists the old store object as a source input, including the root derivation.
2014-09-28 09:39:39 -04:00
Shea Levy 553e1b16f0 replace-dependency: Eelco has ruled, lowerCamelCase > dash-case :( 2013-01-13 11:15:01 -05:00
Shea Levy 96a834d42a replace-dependency: Better function names 2013-01-11 16:16:20 -05:00
Shea Levy 5dd1b8f204 replace-dependency: Don't strictly require that drv, old-dependency, and new-dependency be derivations 2013-01-11 16:13:58 -05:00
Shea Levy 779c74f795 Remove some artifacts of a failed attempt from replace-dependency 2013-01-11 16:09:07 -05:00
Shea Levy d1662d7155 Add the replace-dependency build support function.
The use case is to do a deep replacement of a dependency without rebuilding the entire tree.
For example, suppose a security hole is found in glibc and a patch released. Ideally, you'd
just rebuild everything, but that takes time, space, and CPU that you might not have, so in
the mean time you could build a safe version of, say, firefox with:

  firefox-safe = replace-dependency { drv = firefox; old-dependency = glibc; new-dependency = patched-glibc; };

Building firefox-safe will rebuild glibc, but only do a simple copy/string replacement on all other dependencies
of firefox. On my system (MBP 13" mid-2012), after a new glibc had been build building firefox took around 11 seconds.

See the comments in the file for more details.
2013-01-11 14:42:09 -05:00