Return errors from blameDeletedLines instead of just logging them

I guess when I originally wrote this code I just didn't know how to do that...

9 files changed, 233 insertions, 13 deletions

diff --git a/go.mod b/go.mod
index 6e7d87686..e76dfa800 100644
--- a/go.mod
+++ b/go.mod
@@ -38,6 +38,7 @@ require (
 	github.com/stretchr/testify v1.8.1
 	github.com/xo/terminfo v0.0.0-20210125001918-ca9a967f8778
 	golang.org/x/exp v0.0.0-20220318154914-8dddf5d87bd8
+	golang.org/x/sync v0.7.0
 	gopkg.in/ozeidan/fuzzy-patricia.v3 v3.0.0
 	gopkg.in/yaml.v3 v3.0.1
 )
diff --git a/go.sum b/go.sum
index ae6adb231..31ef8cb76 100644
--- a/go.sum
+++ b/go.sum
@@ -423,6 +423,8 @@ golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20170407050850-f3918c30c5c2/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
diff --git a/pkg/gui/controllers/helpers/fixup_helper.go b/pkg/gui/controllers/helpers/fixup_helper.go
index ef4bb315e..f57e8f2f9 100644
--- a/pkg/gui/controllers/helpers/fixup_helper.go
+++ b/pkg/gui/controllers/helpers/fixup_helper.go
@@ -5,13 +5,13 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
-	"sync"
 
 	"github.com/jesseduffield/generics/set"
 	"github.com/jesseduffield/lazygit/pkg/commands/models"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
 	"github.com/jesseduffield/lazygit/pkg/utils"
 	"github.com/samber/lo"
+	"golang.org/x/sync/errgroup"
 )
 
 type FixupHelper struct {
@@ -56,7 +56,10 @@ func (self *FixupHelper) HandleFindBaseCommitForFixupPress() error {
 		return errors.New(self.c.Tr.NoDeletedLinesInDiff)
 	}
 
-	hashes := self.blameDeletedLines(deletedLineHunks)
+	hashes, err := self.blameDeletedLines(deletedLineHunks)
+	if err != nil {
+		return err
+	}
 
 	if len(hashes) == 0 {
 		// This should never happen
@@ -185,29 +188,29 @@ func parseDiff(diff string) ([]*hunk, []*hunk) {
 }
 
 // returns the list of commit hashes that introduced the lines which have now been deleted
-func (self *FixupHelper) blameDeletedLines(deletedLineHunks []*hunk) []string {
-	var wg sync.WaitGroup
+func (self *FixupHelper) blameDeletedLines(deletedLineHunks []*hunk) ([]string, error) {
+	errg := errgroup.Group{}
 	hashChan := make(chan string)
 
 	for _, h := range deletedLineHunks {
-		wg.Add(1)
-		go func(h *hunk) {
-			defer wg.Done()
-
+		errg.Go(func() error {
 			blameOutput, err := self.c.Git().Blame.BlameLineRange(h.filename, "HEAD", h.startLineIdx, h.numLines)
 			if err != nil {
-				self.c.Log.Errorf("Error blaming file '%s': %v", h.filename, err)
-				return
+				return err
 			}
 			blameLines := strings.Split(strings.TrimSuffix(blameOutput, "\n"), "\n")
 			for _, line := range blameLines {
 				hashChan <- strings.Split(line, " ")[0]
 			}
-		}(h)
+			return nil
+		})
 	}
 
 	go func() {
-		wg.Wait()
+		// We don't care about the error here, we'll check it later (in the
+		// return statement below). Here we only wait for all the goroutines to
+		// finish so that we can close the channel.
+		_ = errg.Wait()
 		close(hashChan)
 	}()
 
@@ -216,5 +219,5 @@ func (self *FixupHelper) blameDeletedLines(deletedLineHunks []*hunk) []string {
 		result.Add(hash)
 	}
 
-	return result.ToSlice()
+	return result.ToSlice(), errg.Wait()
 }
diff --git a/vendor/golang.org/x/sync/LICENSE b/vendor/golang.org/x/sync/LICENSE
new file mode 100644
index 000000000..6a66aea5e
--- /dev/null
+++ b/vendor/golang.org/x/sync/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/golang.org/x/sync/PATENTS b/vendor/golang.org/x/sync/PATENTS
new file mode 100644
index 000000000..733099041
--- /dev/null
+++ b/vendor/golang.org/x/sync/PATENTS
@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.
diff --git a/vendor/golang.org/x/sync/errgroup/errgroup.go b/vendor/golang.org/x/sync/errgroup/errgroup.go
new file mode 100644
index 000000000..948a3ee63
--- /dev/null
+++ b/vendor/golang.org/x/sync/errgroup/errgroup.go
@@ -0,0 +1,135 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package errgroup provides synchronization, error propagation, and Context
+// cancelation for groups of goroutines working on subtasks of a common task.
+//
+// [errgroup.Group] is related to [sync.WaitGroup] but adds handling of tasks
+// returning errors.
+package errgroup
+
+import (
+	"context"
+	"fmt"
+	"sync"
+)
+
+type token struct{}
+
+// A Group is a collection of goroutines working on subtasks that are part of
+// the same overall task.
+//
+// A zero Group is valid, has no limit on the number of active goroutines,
+// and does not cancel on error.
+type Group struct {
+	cancel func(error)
+
+	wg sync.WaitGroup
+
+	sem chan token
+
+	errOnce sync.Once
+	err     error
+}
+
+func (g *Group) done() {
+	if g.sem != nil {
+		<-g.sem
+	}
+	g.wg.Done()
+}
+
+// WithContext returns a new Group and an associated Context derived from ctx.
+//
+// The derived Context is canceled the first time a function passed to Go
+// returns a non-nil error or the first time Wait returns, whichever occurs
+// first.
+func WithContext(ctx context.Context) (*Group, context.Context) {
+	ctx, cancel := withCancelCause(ctx)
+	return &Group{cancel: cancel}, ctx
+}
+
+// Wait blocks until all function calls from the Go method have returned, then
+// returns the first non-nil error (if any) from them.
+func (g *Group) Wait() error {
+	g.wg.Wait()
+	if g.cancel != nil {
+		g.cancel(g.err)
+	}
+	return g.err
+}
+
+// Go calls the given function in a new goroutine.
+// It blocks until the new goroutine can be added without the number of
+// active goroutines in the group exceeding the configured limit.
+//
+// The first call to return a non-nil error cancels the group's context, if the
+// group was created by calling WithContext. The error will be returned by Wait.
+func (g *Group) Go(f func() error) {
+	if g.sem != nil {
+		g.sem <- token{}
+	}
+
+	g.wg.Add(1)
+	go func() {
+		defer g.done()
+
+		if err := f(); err != nil {
+			g.errOnce.Do(func() {
+				g.err = err
+				if g.cancel != nil {
+					g.cancel(g.err)
+				}
+			})
+		}
+	}()
+}
+
+// TryGo calls the given function in a new goroutine only if the number of
+// active goroutines in the group is currently below the configured limit.
+//
+// The return value reports whether the goroutine was started.
+func (g *Group) TryGo(f func() error) bool {
+	if g.sem != nil {
+		select {
+		case g.sem <- token{}:
+			// Note: this allows barging iff channels in general allow barging.
+		default:
+			return false
+		}
+	}
+
+	g.wg.Add(1)
+	go func() {
+		defer g.done()
+
+		if err := f(); err != nil {
+			g.errOnce.Do(func() {
+				g.err = err
+				if g.cancel != nil {
+					g.cancel(g.err)
+				}
+			})
+		}
+	}()
+	return true
+}
+
+// SetLimit limits the number of active goroutines in this group to at most n.
+// A negative value indicates no limit.
+//
+// Any subsequent call to the Go method will block until it can add an active
+// goroutine without exceeding the configured limit.
+//
+// The limit must not be modified while any goroutines in the group are active.
+func (g *Group) SetLimit(n int) {
+	if n < 0 {
+		g.sem = nil
+		return
+	}
+	if len(g.sem) != 0 {
+		panic(fmt.Errorf("errgroup: modify limit while %v goroutines in the group are still active", len(g.sem)))
+	}
+	g.sem = make(chan token, n)
+}
diff --git a/vendor/golang.org/x/sync/errgroup/go120.go b/vendor/golang.org/x/sync/errgroup/go120.go
new file mode 100644
index 000000000..f93c740b6
--- /dev/null
+++ b/vendor/golang.org/x/sync/errgroup/go120.go
@@ -0,0 +1,13 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.20
+
+package errgroup
+
+import "context"
+
+func withCancelCause(parent context.Context) (context.Context, func(error)) {
+	return context.WithCancelCause(parent)
+}
diff --git a/vendor/golang.org/x/sync/errgroup/pre_go120.go b/vendor/golang.org/x/sync/errgroup/pre_go120.go
new file mode 100644
index 000000000..88ce33434
--- /dev/null
+++ b/vendor/golang.org/x/sync/errgroup/pre_go120.go
@@ -0,0 +1,14 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.20
+
+package errgroup
+
+import "context"
+
+func withCancelCause(parent context.Context) (context.Context, func(error)) {
+	ctx, cancel := context.WithCancel(parent)
+	return ctx, func(error) { cancel() }
+}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 881770146..cc44834f2 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -313,6 +313,9 @@ golang.org/x/exp/slices
 golang.org/x/net/context
 golang.org/x/net/internal/socks
 golang.org/x/net/proxy
+# golang.org/x/sync v0.7.0
+## explicit; go 1.18
+golang.org/x/sync/errgroup
 # golang.org/x/sys v0.19.0
 ## explicit; go 1.18
 golang.org/x/sys/cpu