git: Extract helper function to convert config pairs to envvars

We'll need to convert config pairs into Git configuration environment
variables so that we can inject them into the Ruby sidecar. Extract the
code that does this from `WithConfigEnv()` into a separate helper to
prepare for this change.

2 files changed, 63 insertions, 11 deletions

diff --git a/internal/git/command_options.go b/internal/git/command_options.go
index 6b9f8dbb7..ca31b88ce 100644
--- a/internal/git/command_options.go
+++ b/internal/git/command_options.go
@@ -82,6 +82,21 @@ func (cp ConfigPair) GlobalArgs() ([]string, error) {
 	return []string{"-c", fmt.Sprintf("%s=%s", cp.Key, cp.Value)}, nil
 }
 
+// ConfigPairsToGitEnvironment converts the given config pairs into a set of environment variables
+// that can be injected into a Git executable.
+func ConfigPairsToGitEnvironment(configPairs []ConfigPair) []string {
+	env := make([]string, 0, len(configPairs)*2+1)
+
+	for i, configPair := range configPairs {
+		env = append(env,
+			fmt.Sprintf("GIT_CONFIG_KEY_%d=%s", i, configPair.Key),
+			fmt.Sprintf("GIT_CONFIG_VALUE_%d=%s", i, configPair.Value),
+		)
+	}
+
+	return append(env, fmt.Sprintf("GIT_CONFIG_COUNT=%d", len(configPairs)))
+}
+
 // Flag is a single token optional command line argument that enables or
 // disables functionality (e.g. "-L")
 type Flag struct {
@@ -210,17 +225,7 @@ func WithConfig(configPairs ...ConfigPair) CmdOpt {
 // via the process's command line.
 func WithConfigEnv(configPairs ...ConfigPair) CmdOpt {
 	return func(_ context.Context, _ config.Cfg, _ CommandFactory, c *cmdCfg) error {
-		env := make([]string, 0, len(configPairs)*2+1)
-
-		for i, configPair := range configPairs {
-			env = append(env,
-				fmt.Sprintf("GIT_CONFIG_KEY_%d=%s", i, configPair.Key),
-				fmt.Sprintf("GIT_CONFIG_VALUE_%d=%s", i, configPair.Value),
-			)
-		}
-		env = append(env, fmt.Sprintf("GIT_CONFIG_COUNT=%d", len(configPairs)))
-
-		c.env = append(c.env, env...)
+		c.env = append(c.env, ConfigPairsToGitEnvironment(configPairs)...)
 		return nil
 	}
 }
diff --git a/internal/git/command_options_test.go b/internal/git/command_options_test.go
index 9a8dfa1d8..95d874384 100644
--- a/internal/git/command_options_test.go
+++ b/internal/git/command_options_test.go
@@ -465,3 +465,50 @@ func TestWithInternalFetch(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigPairsToEnvironment(t *testing.T) {
+	for _, tc := range []struct {
+		desc        string
+		configPairs []ConfigPair
+		expectedEnv []string
+	}{
+		{
+			desc: "no pairs",
+			expectedEnv: []string{
+				"GIT_CONFIG_COUNT=0",
+			},
+		},
+		{
+			desc: "single pair",
+			configPairs: []ConfigPair{
+				{Key: "foo.bar", Value: "baz"},
+			},
+			expectedEnv: []string{
+				"GIT_CONFIG_KEY_0=foo.bar",
+				"GIT_CONFIG_VALUE_0=baz",
+				"GIT_CONFIG_COUNT=1",
+			},
+		},
+		{
+			desc: "multiple pairs",
+			configPairs: []ConfigPair{
+				{Key: "duplicate.key", Value: "first"},
+				{Key: "foo.bar", Value: "baz"},
+				{Key: "duplicate.key", Value: "second"},
+			},
+			expectedEnv: []string{
+				"GIT_CONFIG_KEY_0=duplicate.key",
+				"GIT_CONFIG_VALUE_0=first",
+				"GIT_CONFIG_KEY_1=foo.bar",
+				"GIT_CONFIG_VALUE_1=baz",
+				"GIT_CONFIG_KEY_2=duplicate.key",
+				"GIT_CONFIG_VALUE_2=second",
+				"GIT_CONFIG_COUNT=3",
+			},
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			require.Equal(t, tc.expectedEnv, ConfigPairsToGitEnvironment(tc.configPairs))
+		})
+	}
+}