feat: improve context in error advice messages

Provide more context information in the error messages propagated from
advice application errors, so that they are easier to troubleshoot.
These messages aim to provide a lineage that allows maintainers to know
exactly what advice failed, on what file.

internal/injector/aspect/advice/assign.go

@@ -26,12 +26,12 @@
 func (a *assignValue) Apply(ctx context.AdviceContext) (bool, error) {
 	spec, ok := ctx.Node().(*dst.ValueSpec)
 	if !ok {
-		return false, fmt.Errorf("expected *dst.ValueSpec, got %T", ctx.Node())
+		return false, fmt.Errorf("assign-value: expected *dst.ValueSpec, got %T", ctx.Node())
 	}
 
 	expr, err := a.Template.CompileExpression(ctx)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("assign-value: %w", err)
 	}
 
 	spec.Values = make([]dst.Expr, len(spec.Names))

internal/injector/aspect/advice/block.go

@@ -29,12 +29,12 @@
 func (a *prependStatements) Apply(ctx context.AdviceContext) (bool, error) {
 	block, ok := ctx.Node().(*dst.BlockStmt)
 	if !ok {
-		return false, fmt.Errorf("expected *dst.BlockStmt, got %T", ctx.Node())
+		return false, fmt.Errorf("prepend-statements: expected *dst.BlockStmt, got %T", ctx.Node())
 	}
 
 	stmts, err := a.Template.CompileBlock(ctx)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("prepend-statements: %w", err)
 	}
 
 	list := make([]dst.Stmt, 1+len(block.List))

internal/injector/aspect/advice/call.go

@@ -32,15 +32,15 @@
 func (a *appendArgs) Apply(ctx context.AdviceContext) (bool, error) {
 	call, ok := ctx.Node().(*dst.CallExpr)
 	if !ok {
-		return false, fmt.Errorf("expected a *dst.CallExpr, received %T", ctx.Node())
+		return false, fmt.Errorf("append-arguments: expected a *dst.CallExpr, received %T", ctx.Node())
 	}
 
 	newArgs := make([]dst.Expr, len(a.Templates))
 	var err error
 	for i, t := range a.Templates {
 		newArgs[i], err = t.CompileExpression(ctx)
 		if err != nil {
-			return false, err
+			return false, fmt.Errorf("append-arguments[%d]: %w", i, err)
 		}
 		ctx.EnsureMinGoLang(t.Lang)
 	}

internal/injector/aspect/advice/inject.go

@@ -6,6 +6,8 @@
 package advice
 
 import (
+	"fmt"
+
 	"github.com/DataDog/orchestrion/internal/fingerprint"
 	"github.com/DataDog/orchestrion/internal/injector/aspect/advice/code"
 	"github.com/DataDog/orchestrion/internal/injector/aspect/context"
@@ -26,7 +28,7 @@
 func (a injectDeclarations) Apply(ctx context.AdviceContext) (bool, error) {
 	decls, err := a.Template.CompileDeclarations(ctx)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("inject-declarations: %w", err)
 	}
 
 	if len(decls) == 0 {

internal/injector/aspect/advice/wrap.go

@@ -33,12 +33,12 @@
 		ctx = ctx.Child(kve.Value, "Value", -1)
 		defer ctx.Release()
 	} else if _, ok = ctx.Node().(dst.Expr); !ok {
-		return false, fmt.Errorf("expected dst.Expr or *dst.KeyValueExpr, got %T", ctx.Node())
+		return false, fmt.Errorf("wrap-expression: expected dst.Expr or *dst.KeyValueExpr, got %T", ctx.Node())
 	}
 
 	repl, err := a.Template.CompileExpression(ctx)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("wrap-expression: %w", err)
 	}
 
 	if kve == nil {

internal/injector/injector.go

@@ -159,7 +159,7 @@
 	var err error
 	result.Modified, result.References, result.GoLang, err = i.applyAspects(decorator, file, i.RootConfig, typeInfo)
 	if err != nil {
-		return result, err
+		return result, fmt.Errorf("%q: %w", result.Filename, err)
 	}
 
 	if result.Modified {
@@ -239,14 +239,14 @@
 		if !inj.JoinPoint.Matches(ctx) {
 			continue
 		}
-		for _, act := range inj.Advice {
+		for idx, act := range inj.Advice {
 			var changed bool
 			changed, err = act.Apply(ctx)
 			if changed {
 				mod = true
 			}
 			if err != nil {
-				return
+				return mod, fmt.Errorf("%q[%d]: %w", inj.ID, idx, err)
 			}
 		}
 	}