🐛 Use lazy evaluation for shell calls in Makefile#3154
Merged
k8s-ci-robot merged 1 commit intokubernetes-sigs:mainfrom May 5, 2026
Merged
🐛 Use lazy evaluation for shell calls in Makefile#3154k8s-ci-robot merged 1 commit intokubernetes-sigs:mainfrom
Makefile#3154k8s-ci-robot merged 1 commit intokubernetes-sigs:mainfrom
Conversation
Variables assigned using `:=` (simply expanded variable assignment [1]) are expanded once, immediately when the line is read. This can be problematic when the shell function is used, since that is expanded when make reads the line [2]. Combined, this means any `$(shell ...)` invocations on a `:=` line run at parse time rather than execution time. Avoid this by assigning these variables using using `=` (recursively expanded variable assignment [3]), which causes them to be evaluated lazily. This allows us to tab-complete targets without a 2-3 second delay. [1] https://www.gnu.org/software/make/manual/html_node/Simple-Assignment.html [2] https://www.gnu.org/software/make/manual/make.html#Shell-Function [3] https://www.gnu.org/software/make/manual/html_node/Recursive-Assignment.html Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
k8s-ci-robot
added
the
do-not-merge/hold
✅ Deploy Preview for kubernetes-sigs-cluster-api-openstack ready!
To edit notification comments on pull requests, go to your Netlify project configuration. |
k8s-ci-robot
added
size/XS
Contributor
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: lentzi90 The full list of commands accepted by this bot can be found here. The pull request process is described here DetailsNeeds approval from an approver in each of these files:
Approvers can indicate their approval by writing |
k8s-ci-robot
added
the
approved
k8s-ci-robot
added
the
lgtm
Contributor
Author
|
/remove-hold |
k8s-ci-robot
removed
the
do-not-merge/hold
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What this PR does / why we need it:
Variables assigned using
:=(simply expanded variable assignment) are expanded once, immediately when the line is read. This can be problematic when the shell function is used, since that is expanded when make reads the line. Combined, this means any$(shell ...)invocations on a:=line run at parse time rather than execution time.Avoid this by assigning these variables using using
=(recursively expanded variable assignment), which causes them to be evaluated lazily. This allows us to tab-complete targets without a 2-3 second delay.Which issue(s) this PR fixes (optional, in
fixes #<issue number>(, fixes #<issue_number>, ...)format, will close the issue(s) when PR gets merged):n/a
Special notes for your reviewer:
None.
/hold