Release Notes:

…y` (#27995)

Bazel crashes at HEAD when `use_repo_rule` is used with
`local_repository` while also using `--inject_repository`.

Make bugs like this less likely by extracting out a safe "get or create"
helper for extension usages.

Fixes #27953

Closes #27967.

PiperOrigin-RevId: 844683022
Change-Id: I1edcf1e7c72ef8d46c67e51b4f9ffd6a6ce82ec8

Commit
21d7fec

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>

All the values have to be checked for nullness individually.

Fixes the following two NPEs:
1.
bazel-contrib/rules_go#4531 (comment)
```
java.lang.NullPointerException: Cannot invoke "com.google.devtools.build.lib.skyframe.PackageValue.getPackage()" because the return value of "com.google.devtools.build.skyframe.SkyframeLookupResult.getOrThrow(com.google.devtools.build.skyframe.SkyKey, java.lang.Class)" is null
	at com.google.devtools.build.lib.skyframe.TestExpansionFunction.getPrerequisites(TestExpansionFunction.java:169)
	at com.google.devtools.build.lib.skyframe.TestExpansionFunction.computeExpandedTests(TestExpansionFunction.java:85)
...
```
2. #27942
```
java.lang.NullPointerException
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at com.google.devtools.build.lib.skyframe.DirectoryTreeDigestFunction.getSubDirTreeDigests(DirectoryTreeDigestFunction.java:140)
	at com.google.devtools.build.lib.skyframe.DirectoryTreeDigestFunction.compute(DirectoryTreeDigestFunction.java:65)
```

Speculative fix for #27942

Closes #27959.

PiperOrigin-RevId: 843808256
Change-Id: I012756ec8a641c68bca31fe155d230caa00d8a3f

Commit
1025821

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>

…s unavailable (#27996)

Cherry-picking #27846.

---------

Co-authored-by: Chi Wang <coeuvre@gmail.com>

…okup in (#28027)

ToolchainTypeUtils is incomplete.

PiperOrigin-RevId: 702010313
Change-Id: I24983bd2a1c708f7f8f63ee87273e22ecddb3a72

Commit
7e4fb41

Co-authored-by: Googler <jcater@google.com>

…nly` (#28116)

This avoids action conflicts when `testonly` non-test targets depend on
test targets.

Until `--incompatible_check_testonly_for_output_files` is flipped, it is
still possible to get action conflicts when a non-`testonly` target
depends on an output file of a test. Since this can be fixed by adding
the missing `testonly` annotation, this is only a minor concern.

Fixes #28056

Closes #28073.

PiperOrigin-RevId: 847892897
Change-Id: I60e908a22b51c307306760aa054b3968cfbebac2

Commit
bcd8bcb

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>

)

This reverts commit 65fe463.

Breaks repo rules that hit a download cache entry and subsequently
attempt to overwrite the file (e.g. http_archive's handling of remote
module files).

Keeps the added test as it doesn't depend on the change.

Work towards #28031

Closes #28148.

PiperOrigin-RevId: 852373210
Change-Id: I9e5e9ae87696068fbcb41cfd4dc77c36fea8248b

Commit
d5dba3f

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>

Work towards #28056

Closes #28061.

PiperOrigin-RevId: 852463750
Change-Id: I100a76adf564aa11dbef1a98f48a6b1389c1d584

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>