Extract the diff.noprefix override into a GitCommandBuilder method

Seven diff commands pass -c diff.noprefix=false so that the paths in
their output carry a prefix. The next commits use the override for
more commands and add more config to it, so give it a single home
first.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pkg/commands/git_commands/commit.go

@@ -242,7 +242,7 @@ func (self *CommitCommands) AmendHeadCmdObj() *oscommands.CmdObj {
 
 func (self *CommitCommands) ShowCmdObj(hash string, filterPaths []string, mode DiffMode) *oscommands.CmdObj {
 	cmdArgs := NewGitCmd("show").
-		Config("diff.noprefix=false").
+		ParseableDiffPrefixes().
 		AddCommonDiffArgs(self.diffRendererConfigManager, self.UserConfig(), mode).
 		Arg("--submodule").
 		Arg("--color=" + mode.colorArg(self.diffRendererConfigManager)).

pkg/commands/git_commands/commit_file_loader.go

@@ -24,7 +24,7 @@ func NewCommitFileLoader(common *common.Common, cmd oscommands.ICmdObjBuilder) *
 // GetFilesInDiff get the specified commit files
 func (self *CommitFileLoader) GetFilesInDiff(from string, to string, reverse bool) ([]*models.CommitFile, error) {
 	cmdArgs := NewGitCmd("diff").
-		Config("diff.noprefix=false").
+		ParseableDiffPrefixes().
 		Arg("--submodule").
 		Arg("--no-ext-diff").
 		Arg("--name-status").

pkg/commands/git_commands/diff.go

@@ -146,7 +146,7 @@ func NewDiffCommands(gitCommon *GitCommon) *DiffCommands {
 func (self *DiffCommands) DiffCmdObj(diffArgs []string, mode DiffMode) *oscommands.CmdObj {
 	return self.cmd.New(
 		NewGitCmd("diff").
-			Config("diff.noprefix=false").
+			ParseableDiffPrefixes().
 			AddCommonDiffArgs(self.diffRendererConfigManager, self.UserConfig(), mode).
 			Arg("--submodule").
 			Arg(fmt.Sprintf("--color=%s", mode.colorArg(self.diffRendererConfigManager))).
@@ -188,7 +188,7 @@ func (self *DiffCommands) CustomPatchDiffCmdObj(dir string, mode DiffMode) *osco
 func (self *DiffCommands) GetDiff(staged bool, additionalArgs ...string) (string, error) {
 	return self.cmd.New(
 		NewGitCmd("diff").
-			Config("diff.noprefix=false").
+			ParseableDiffPrefixes().
 			Arg("--no-ext-diff", "--no-color").
 			ArgIf(staged, "--staged").
 			Dir(self.repoPaths.worktreePath).
@@ -238,7 +238,7 @@ func (self *DiffCommands) OpenDiffToolCmdObj(opts DiffToolCmdOptions) *oscommand
 func (self *DiffCommands) DiffIndexCmdObj(diffArgs ...string) *oscommands.CmdObj {
 	return self.cmd.New(
 		NewGitCmd("diff-index").
-			Config("diff.noprefix=false").
+			ParseableDiffPrefixes().
 			Arg("--submodule", "--no-ext-diff", "--no-color", "--patch").
 			Arg(diffArgs...).ToArgv(),
 	)

pkg/commands/git_commands/git_command_builder.go

@@ -144,6 +144,14 @@ func (self *GitCommandBuilder) NoLineEndingConversion() *GitCommandBuilder {
 		Config("core.safecrlf=false")
 }
 
+// ParseableDiffPrefixes makes git put a prefix in front of the paths of a diff
+// even if the user has set diff.noprefix. We read the paths of the diffs we show
+// out of their headers, and we build patches from them for `git apply`. Both
+// rely on there being a prefix to strip.
+func (self *GitCommandBuilder) ParseableDiffPrefixes() *GitCommandBuilder {
+	return self.Config("diff.noprefix=false")
+}
+
 func (self *GitCommandBuilder) AddCommonDiffArgs(diffRendererConfigManager *config.DiffRendererConfigManager, userConfig *config.UserConfig, mode DiffMode) *GitCommandBuilder {
 	contextSize := userConfig.Git.DiffContextSize
 	useExtDiff := mode == DiffModeRendered && diffRendererConfigManager.GetDiffRendererType() == config.DiffRendererType_ExtDiff

pkg/commands/git_commands/patch.go

@@ -434,7 +434,7 @@ func (self *PatchCommands) PullPatchIntoNewCommitBefore(
 // get the diff of HEAD and the original commit and then apply that.
 func (self *PatchCommands) diffHeadAgainstCommit(commit *models.Commit) (string, error) {
 	cmdArgs := NewGitCmd("diff").
-		Config("diff.noprefix=false").
+		ParseableDiffPrefixes().
 		Arg("--no-ext-diff", "--no-color").
 		Arg("HEAD.." + commit.Hash()).
 		ToArgv()

pkg/commands/git_commands/working_tree.go

@@ -425,7 +425,7 @@ func (self *WorkingTreeCommands) ShowFileDiff(from string, to string, reverse bo
 
 func (self *WorkingTreeCommands) ShowFileDiffCmdObj(from string, to string, reverse bool, fileNames []string, mode DiffMode) *oscommands.CmdObj {
 	cmdArgs := NewGitCmd("diff").
-		Config("diff.noprefix=false").
+		ParseableDiffPrefixes().
 		AddCommonDiffArgs(self.diffRendererConfigManager, self.UserConfig(), mode).
 		Arg("--submodule").
 		Arg(fmt.Sprintf("--color=%s", mode.colorArg(self.diffRendererConfigManager))).