From: Timo Beckers <timo@isovalent.com>
Date: Wed, 5 Nov 2025 12:08:54 +0000 (+0100)
Subject: collection: remove deprecated CollectionSpec.RewriteConstants
X-Git-Url: https://git.feebdaed.xyz/?a=commitdiff_plain;h=589910b6a77d140e70502ab4fe8511a8960c3d24;p=0xmirror%2Febpf.git

collection: remove deprecated CollectionSpec.RewriteConstants

This has been deprecated since v0.17.0. Use CollectionSpec.Variables instead.

Signed-off-by: Timo Beckers <timo@isovalent.com>
---

diff --git a/collection.go b/collection.go
index 83f1b40..a4ce39b 100644
--- a/collection.go
+++ b/collection.go
@@ -94,58 +94,6 @@ func copyMapOfSpecs[T interface{ Copy() T }](m map[string]T) map[string]T {
 	return cpy
 }
 
-// MissingConstantsError is returned by [CollectionSpec.RewriteConstants].
-type MissingConstantsError struct {
-	// The constants missing from .rodata.
-	Constants []string
-}
-
-func (m *MissingConstantsError) Error() string {
-	return fmt.Sprintf("some constants are missing from .rodata: %s", strings.Join(m.Constants, ", "))
-}
-
-// RewriteConstants replaces the value of multiple constants.
-//
-// The constant must be defined like so in the C program:
-//
-//	volatile const type foobar;
-//	volatile const type foobar = default;
-//
-// Replacement values must be of the same length as the C sizeof(type).
-// If necessary, they are marshalled according to the same rules as
-// map values.
-//
-// From Linux 5.5 the verifier will use constants to eliminate dead code.
-//
-// Returns an error wrapping [MissingConstantsError] if a constant doesn't exist.
-//
-// Deprecated: Use [CollectionSpec.Variables] to interact with constants instead.
-// RewriteConstants is now a wrapper around the VariableSpec API.
-func (cs *CollectionSpec) RewriteConstants(consts map[string]interface{}) error {
-	var missing []string
-	for n, c := range consts {
-		v, ok := cs.Variables[n]
-		if !ok {
-			missing = append(missing, n)
-			continue
-		}
-
-		if !v.Constant() {
-			return fmt.Errorf("variable %s is not a constant", n)
-		}
-
-		if err := v.Set(c); err != nil {
-			return fmt.Errorf("rewriting constant %s: %w", n, err)
-		}
-	}
-
-	if len(missing) != 0 {
-		return fmt.Errorf("rewrite constants: %w", &MissingConstantsError{Constants: missing})
-	}
-
-	return nil
-}
-
 // Assign the contents of a CollectionSpec to a struct.
 //
 // This function is a shortcut to manually checking the presence
diff --git a/elf_reader_test.go b/elf_reader_test.go
index f37659a..3861b68 100644
--- a/elf_reader_test.go
+++ b/elf_reader_test.go
@@ -242,33 +242,14 @@ func TestLoadCollectionSpec(t *testing.T) {
 			t.Fatal("Can't parse ELF:", err)
 		}
 
-		err = have.RewriteConstants(map[string]interface{}{
-			"arg":  uint32(1),
-			"arg2": uint32(2),
-		})
-		if err != nil {
-			t.Fatal("Can't rewrite constant:", err)
-		}
-
-		err = have.RewriteConstants(map[string]interface{}{
-			"totallyBogus":  uint32(1),
-			"totallyBogus2": uint32(2),
-		})
-		if err == nil {
-			t.Error("Rewriting a bogus constant doesn't fail")
-		}
-
-		var mErr *MissingConstantsError
-		if !errors.As(err, &mErr) {
-			t.Fatal("Error doesn't wrap MissingConstantsError:", err)
-		}
-		qt.Assert(t, qt.ContentEquals(mErr.Constants, []string{"totallyBogus", "totallyBogus2"}))
-
 		qt.Assert(t, qt.Equals(have.Maps["perf_event_array"].ValueSize, 0))
 		qt.Assert(t, qt.IsNotNil(have.Maps["perf_event_array"].Value))
 
 		qt.Assert(t, qt.CmpEquals(have, coll, csCmpOpts))
 
+		qt.Assert(t, qt.IsNil(have.Variables["arg"].Set(uint32(1))))
+		qt.Assert(t, qt.IsNil(have.Variables["arg2"].Set(uint32(2))))
+
 		if have.ByteOrder != internal.NativeEndian {
 			return
 		}
@@ -361,11 +342,7 @@ func TestFreezeRodata(t *testing.T) {
 		Program *Program `ebpf:"freeze_rodata"`
 	}
 
-	if err := spec.RewriteConstants(map[string]interface{}{
-		"ret": uint32(1),
-	}); err != nil {
-		t.Fatal(err)
-	}
+	qt.Assert(t, qt.IsNil(spec.Variables["ret"].Set(uint32(1))))
 
 	mustLoadAndAssign(t, spec, &obj, nil)
 	obj.Program.Close()