rrbutani

❯ pytest --chrome-trace parallel-baseline.json -n auto --dist=worksteal
664 passed, 24 warnings in 9.08s

❯ pytest --chrome-trace parallel-reordered.json -n auto --dist=worksteal --expensive-tests-first

rrbutani

observations:

1. path mapping does not really[^1] "mask" out the repo name from non-main repo paths: source files OR generated artifacts
   • this means that whether you build a particular target (or really produce a particular action for the target) when that target is in the main (root) repo vs. when its in an "external" repo effects the paths used in the action
   • i.e. you will not get cache hits if you build //:your_target and then pull your repo into another bazel workspace as @foo and build @foo//:your_target
   • TODO: would be nice to repo names as well...
2. path mapping silently falls back to using unmapped paths if the set of mapped paths has any conflicts (see :example_both)

• note that ctx.actions.run(_shell)'s inputs does influence path mapping and does appear to factor into how conflicts are detected but... if you try to add a path to the command line (i.e. via arguments) that you haven't listed in inputs it isn't an error — some path mapping heuristi

rrbutani

Enforcement of allowed dep edges

the idea is to have testonly-esque checks

consider a project where we want to partition content (for an existing rule) into three categories:

• "open-source"; a.k.a. oss
• "proprietary"; a.k.a. prp
• "development-only"; a.k.a. dev

rrbutani

see https://www.gnu.org/software/make/manual/html_node/General-Search.html

from the perspective of a recipe (i.e. automatic variables), prerequisites are "rewritten"; if they're resolved to a directory in VPATH, the prereq is prefixed with that directory

rrbutani

see here for .section directive flags and _type_s

• also see the solaris ELF object file format docs

https://c.godbolt.org/z/T4j9GP91n https://assembly.godbolt.org/z/TGnGMWWWd

conflicting linker section flags?

i.e.:

rrbutani

see:

• https://ninja-build.org/manual.html#ref_dependencies
• https://fuchsia.dev/fuchsia-src/development/build/ninja_how#order-only_inputs
• https://github.com/ninja-build/ninja/blob/d60673d49e4facef8579eebeb818318c5b744b0b/src/graph.h#L239-L240
• https://www.gnu.org/software/make/manual/html_node/Prerequisite-Types.html

semantics of order-only deps:

• when deciding whether to rebuild a target, the mtimes (or existence) of order-only deps are not considered
• if the target is built (i.e. due to a normal prereq that was newer), it will wait on order-only deps
• even if the target is not built (i.e. up to date), order-only deps will be scheduled for building (if out of date)

rrbutani

see comment in Makefile

rrbutani

what

tests the we can "project" particular files out of a TreeArtifact for consumption in downstream rules

the intent is that by doing this projection:

• downstream rules that operate on files (not directories — i.e. not TreeArtifact aware) can consume our artifact
• sensitivity in downstream targets is narrowed to only the files in the TreeArtifact that are projected out

rrbutani

0: [.]      succ(a,  ): add `1` to `a`
1: [+]       add(a, b): ret = a; ret =       succ(ret)    `b`     times
2: [*]       mul(a, b): ret = 0; ret =        add(ret, a) `b`     times
3: [^]       exp(a, b): ret = 1; ret =        mul(ret, a) `b`     times
4: [!] tetration(a, b): ret = a; ret =        exp(ret, a) `b - 1` times (special case b = 0 -> 1)
5: [@] pentation(a, b): ret = a; ret =  tetration(ret, a) `b - 1` times (special case b = 0 -> 1)
6: [#]  hexation(a, b): ret = a; ret =  pentation(ret, a) `b - 1` times (special case b = 0 -> 1)

3 .   -> 4
3 + 4 -> 7                 { ((((3 .  ) .  ) .  ) .  ) }

rrbutani

use std::{
    cell::UnsafeCell,
    marker::PhantomData,
    sync::{
        OnceLock,
        mpsc::{Receiver, Sender, channel},
    },
};

// initialized from thread that can call ui stuff