Remove the RemoveDir step with no replacement. This step had no valid
purpose. Mutating source files? That should be done with
UpdateSourceFiles step. Deleting temporary directories? That required
creating the tmp directories in the configure phase which is broken.
Deleting cached artifacts? That's going to cause problems.
Similarly, remove the `Build.makeTempPath` function. This was used to
create a temporary path in the configure place which, again, is the
wrong place to do it.
Instead, the WriteFile step has been updated with more functionality:
tmp mode: In this mode, the directory will be placed inside "tmp" rather
than "o", and caching will be skipped. During the `make` phase, the step
will always do all the file system operations, and on successful build
completion, the dir will be deleted along with all other tmp
directories. The directory is therefore eligible to be used for
mutations by other steps. `Build.addTempFiles` is introduced to
initialize a WriteFile step with this mode.
mutate mode: The operations will not be performed against a freshly
created directory, but instead act against a temporary directory.
`Build.addMutateFiles` is introduced to initialize a WriteFile step with
this mode.
`Build.tmpPath` is introduced, which is a shortcut for
`Build.addTempFiles` followed by `WriteFile.getDirectory`.
* give Cache a gpa rather than arena because that's what it asks for
Adds a variant to the LazyPath union representing a parent directory
of a generated path.
```zig
const LazyPath = union(enum) {
generated_dirname: struct {
generated: *const GeneratedFile,
up: usize,
},
// ...
}
```
These can be constructed with the new method:
```zig
pub fn dirname(self: LazyPath) LazyPath
```
For the cases where the LazyPath is already known
(`.path`, `.cwd_relative`, and `dependency`)
this is evaluated right away.
For dirnames of generated files and their dirnames,
this is evaluated at getPath time.
dirname calls can be chained, but for safety,
they are not allowed to escape outside a root
defined for each case:
- path: This is relative to the build root,
so dirname can't escape outside the build root.
- generated: Can't escape the zig-cache.
- cwd_relative: This can be a relative or absolute path.
If relative, can't escape the current directory,
and if absolute, can't go beyond root (/).
- dependency: Can't escape the dependency's root directory.
Testing:
I've included a standalone case for many of the happy cases.
I couldn't find an easy way to test the negatives, though,
because tests cannot yet expect panics.
Andrew Kelley