Support configurable timestamps in git blame output (#1157)

New CLI/config option is introduced: blame-timestamp-output-format.

Fixes #1157.

5 files changed, 64 insertions, 3 deletions

diff --git a/manual/src/full---help-output.md b/manual/src/full---help-output.md
index 428d81cd..d7451562 100644
--- a/manual/src/full---help-output.md
+++ b/manual/src/full---help-output.md
@@ -49,6 +49,13 @@ OPTIONS:
             
             [default: "%Y-%m-%d %H:%M:%S %z"]
 
+        --blame-timestamp-output-format <FMT>
+            Format string for git blame timestamp output.
+            
+            This string is used for formatting the timestamps in git blame output. It must follow the `strftime` format syntax specification. If it is not present, the timestamps will be formatted in a human-friendly but possibly less accurate form.
+            
+            See: (https://docs.rs/chrono/latest/chrono/format/strftime/index.html)
+
         --color-only
             Do not alter the input structurally in any way.
             
diff --git a/src/cli.rs b/src/cli.rs
index 14b0e231..ead9b2e2 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -260,6 +260,16 @@ pub struct Opt {
     /// Format of `git blame` timestamp in raw git output received by delta.
     pub blame_timestamp_format: String,
 
+    #[clap(long = "blame-timestamp-output-format", value_name = "FMT")]
+    /// Format string for git blame timestamp output.
+    ///
+    /// This string is used for formatting the timestamps in git blame output. It must follow
+    /// the `strftime` format syntax specification. If it is not present, the timestamps will
+    /// be formatted in a human-friendly but possibly less accurate form.
+    ///
+    /// See: (https://docs.rs/chrono/latest/chrono/format/strftime/index.html)
+    pub blame_timestamp_output_format: Option<String>,
+
     #[clap(long = "color-only")]
     /// Do not alter the input structurally in any way.
     ///
diff --git a/src/config.rs b/src/config.rs
index c6d7ef51..4da616a7 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -40,6 +40,7 @@ pub struct Config {
     pub blame_palette: Vec<String>,
     pub blame_separator_style: Option<Style>,
     pub blame_timestamp_format: String,
+    pub blame_timestamp_output_format: Option<String>,
     pub color_only: bool,
     pub commit_regex: Regex,
     pub commit_style: Style,
@@ -240,6 +241,7 @@ impl From<cli::Opt> for Config {
             blame_separator_format: parse_blame_line_numbers(&opt.blame_separator_format),
             blame_separator_style: styles.remove("blame-separator-style"),
             blame_timestamp_format: opt.blame_timestamp_format,
+            blame_timestamp_output_format: opt.blame_timestamp_output_format,
             commit_style: styles["commit-style"],
             color_only: opt.color_only,
             commit_regex,
diff --git a/src/handlers/blame.rs b/src/handlers/blame.rs
index 5ec7e9ff..0e21f6bc 100644
--- a/src/handlers/blame.rs
+++ b/src/handlers/blame.rs
@@ -269,9 +269,12 @@ pub fn format_blame_metadata(
         let width = placeholder.width.unwrap_or(15);
 
         let field = match placeholder.placeholder {
-            Some(Placeholder::Str("timestamp")) => Some(Cow::from(
-                chrono_humanize::HumanTime::from(blame.time).to_string(),
-            )),
+            Some(Placeholder::Str("timestamp")) => {
+                Some(Cow::from(match &config.blame_timestamp_output_format {
+                    Some(time_format) => blame.time.format(time_format).to_string(),
+                    None => chrono_humanize::HumanTime::from(blame.time).to_string(),
+                }))
+            }
             Some(Placeholder::Str("author")) => Some(Cow::from(blame.author)),
             Some(Placeholder::Str("commit")) => Some(delta::format_raw_line(blame.commit, config)),
             None => None,
@@ -409,6 +412,33 @@ mod tests {
     }
 
     #[test]
+    fn test_format_blame_metadata_with_default_timestamp_output_format() {
+        let format_data = format::FormatStringPlaceholderData {
+            placeholder: Some(Placeholder::Str("timestamp")),
+            ..Default::default()
+        };
+        let blame = make_blame_line_with_time("1996-12-19T16:39:57-08:00");
+        let config = integration_test_utils::make_config_from_args(&[]);
+        let regex = Regex::new(r"^\d+ years ago$").unwrap();
+        let result = format_blame_metadata(&[format_data], &blame, &config);
+        assert!(regex.is_match(result.trim()));
+    }
+
+    #[test]
+    fn test_format_blame_metadata_with_custom_timestamp_output_format() {
+        let format_data = format::FormatStringPlaceholderData {
+            placeholder: Some(Placeholder::Str("timestamp")),
+            ..Default::default()
+        };
+        let blame = make_blame_line_with_time("1996-12-19T16:39:57-08:00");
+        let config = integration_test_utils::make_config_from_args(&[
+            "--blame-timestamp-output-format=%Y-%m-%d %H:%M",
+        ]);
+        let result = format_blame_metadata(&[format_data], &blame, &config);
+        assert_eq!(result.trim(), "1996-12-19 16:39");
+    }
+
+    #[test]
     fn test_color_assignment() {
         let mut writer = Cursor::new(vec![0; 512]);
         let config = integration_test_utils::make_config_from_args(&[
@@ -497,4 +527,15 @@ mod tests {
             .map(|(k, v)| (k.as_str(), v.as_str()))
             .collect()
     }
+
+    fn make_blame_line_with_time(timestamp: &str) -> BlameLine {
+        let time = chrono::DateTime::parse_from_rfc3339(&timestamp).unwrap();
+        return BlameLine {
+            commit: "",
+            author: "",
+            time: time,
+            line_number: 0,
+            code: "",
+        };
+    }
 }
diff --git a/src/options/set.rs b/src/options/set.rs
index 41776516..7cb8b0a7 100644
--- a/src/options/set.rs
+++ b/src/options/set.rs
@@ -132,6 +132,7 @@ pub fn set_options(
             blame_palette,
             blame_separator_style,
             blame_timestamp_format,
+            blame_timestamp_output_format,
             color_only,
             commit_decoration_style,
             commit_regex,