From 91684cc9ca43362db0e546674d53a6322dda039e Mon Sep 17 00:00:00 2001
From: cloudhead <cloudhead@radicle.xyz>
Date: Wed, 3 Jan 2024 12:08:09 +0100
Subject: [PATCH] cli: Add `rad patch diff` command

---
 rad-patch.1.adoc                       |  8 ++++
 radicle-cli/examples/rad-patch-diff.md | 63 ++++++++++++++++++++++++++
 radicle-cli/src/commands/patch.rs      | 43 ++++++++++++++++--
 radicle-cli/src/commands/patch/diff.rs | 36 +++++++++++++++
 radicle-cli/src/commands/patch/list.rs |  2 +-
 radicle-cli/src/commands/patch/show.rs |  4 +-
 radicle-cli/src/git/pretty_diff.rs     | 18 +++++++-
 radicle-cli/tests/commands.rs          | 14 ++++++
 radicle/src/cob/patch.rs               | 21 +++++----
 9 files changed, 190 insertions(+), 19 deletions(-)
 create mode 100644 radicle-cli/examples/rad-patch-diff.md
 create mode 100644 radicle-cli/src/commands/patch/diff.rs

diff --git a/rad-patch.1.adoc b/rad-patch.1.adoc
index f8637b2b..e368a737 100644
--- a/rad-patch.1.adoc
+++ b/rad-patch.1.adoc
@@ -15,6 +15,7 @@ rad-patch - Manage radicle patches.
 *rad patch* [<option>...] +
 *rad patch* _list_ [--all|--merged|--open|--archived|--draft] [<option>...] +
 *rad patch* _show_ <patch-id> [<option>...] +
+*rad patch* _diff_ <patch-id> [--revision <revision-id>] [<option>...] +
 *rad patch* _archive_ <patch-id> [<option>...] +
 *rad patch* _update_ <patch-id> [<option>...] +
 *rad patch* _checkout_ <patch-id> [<option>...] +
@@ -52,6 +53,13 @@ Shows information on the given patch.
 *--patch*, *-p*::                    Show the patch changes in git patch format
 *--verbose*, *-v*::                  Show additional information about the patch
 
+=== diff
+
+Outputs the patch diff, using Radicle's diffing tool.
+
+*<patch-id>*::                       The patch to diff
+*--revision*, *-r <revision-id>*::   The revision to diff (default: latest)
+
 === edit
 
 Edits a patch revision comment. To edit the patch title or description, pass
diff --git a/radicle-cli/examples/rad-patch-diff.md b/radicle-cli/examples/rad-patch-diff.md
new file mode 100644
index 00000000..3d7db547
--- /dev/null
+++ b/radicle-cli/examples/rad-patch-diff.md
@@ -0,0 +1,63 @@
+Using `rad patch diff`, we can output the patch diff:
+
+``` ./README.md
+Hello World!
+```
+```
+$ git checkout -b feature/1
+$ git add README.md
+$ git commit -m "Add README" -q
+$ git push rad HEAD:refs/patches
+```
+```
+$ rad patch diff e432b04
+╭───────────────────────────╮
+│ README.md +1 ❲created❳    │
+├───────────────────────────┤
+│ @@ -0,0 +1,1 @@           │
+│      1     + Hello World! │
+╰───────────────────────────╯
+
+```
+
+If we add another file and update the patch, we can see it in the diff.
+
+``` ./RADICLE.md
+Hello Radicle!
+```
+```
+$ git add RADICLE.md
+$ git commit --amend -q
+$ git push -f
+```
+```
+$ rad patch diff e432b04
+╭─────────────────────────────╮
+│ RADICLE.md +1 ❲created❳     │
+├─────────────────────────────┤
+│ @@ -0,0 +1,1 @@             │
+│      1     + Hello Radicle! │
+╰─────────────────────────────╯
+
+╭─────────────────────────────╮
+│ README.md +1 ❲created❳      │
+├─────────────────────────────┤
+│ @@ -0,0 +1,1 @@             │
+│      1     + Hello World!   │
+╰─────────────────────────────╯
+
+```
+
+Buf if we only want to see the changes from the first revision, we can do that
+too.
+
+```
+$ rad patch diff e432b04 --revision e432b04
+╭───────────────────────────╮
+│ README.md +1 ❲created❳    │
+├───────────────────────────┤
+│ @@ -0,0 +1,1 @@           │
+│      1     + Hello World! │
+╰───────────────────────────╯
+
+```
diff --git a/radicle-cli/src/commands/patch.rs b/radicle-cli/src/commands/patch.rs
index 65d8d888..0dc12c78 100644
--- a/radicle-cli/src/commands/patch.rs
+++ b/radicle-cli/src/commands/patch.rs
@@ -10,6 +10,8 @@ mod comment;
 mod common;
 #[path = "patch/delete.rs"]
 mod delete;
+#[path = "patch/diff.rs"]
+mod diff;
 #[path = "patch/edit.rs"]
 mod edit;
 #[path = "patch/label.rs"]
@@ -53,6 +55,7 @@ Usage
     rad patch [<option>...]
     rad patch list [--all|--merged|--open|--archived|--draft|--authored] [--author <did>]... [<option>...]
     rad patch show <patch-id> [<option>...]
+    rad patch diff <patch-id> [<option>...]
     rad patch archive <patch-id> [<option>...]
     rad patch update <patch-id> [<option>...]
     rad patch checkout <patch-id> [<option>...]
@@ -71,6 +74,10 @@ Show options
     -p, --patch                Show the actual patch diff
     -v, --verbose              Show additional information about the patch
 
+Diff options
+
+    -r, --revision <id>        The revision to diff (default: latest)
+
 Comment options
 
     -m, --message <string>     Provide a comment message via the command-line
@@ -81,14 +88,13 @@ Edit options
 
 Review options
 
-        --revision <id>        Review the given revision of the patch
+    -r, --revision <id>        Review the given revision of the patch
     -p, --patch                Review by patch hunks
         --hunk <index>         Only review a specific hunk
         --accept               Accept a patch or set of hunks
         --reject               Reject a patch or set of hunks
     -U, --unified <n>          Generate diffs with <n> lines of context instead of the usual three
     -d, --delete               Delete a review draft
-    -r, --revision             Review a patch revision
     -m, --message [<string>]   Provide a comment with the review (default: prompt)
 
 Assign options
@@ -146,6 +152,7 @@ Other options
 pub enum OperationName {
     Assign,
     Show,
+    Diff,
     Update,
     Archive,
     Delete,
@@ -200,6 +207,10 @@ pub enum Operation {
         patch_id: Rev,
         diff: bool,
     },
+    Diff {
+        patch_id: Rev,
+        revision_id: Option<Rev>,
+    },
     Update {
         patch_id: Rev,
         base_id: Option<Rev>,
@@ -267,7 +278,10 @@ impl Operation {
             | Operation::Edit { .. }
             | Operation::Redact { .. }
             | Operation::Set { .. } => true,
-            Operation::Show { .. } | Operation::Checkout { .. } | Operation::List { .. } => false,
+            Operation::Show { .. }
+            | Operation::Diff { .. }
+            | Operation::Checkout { .. }
+            | Operation::List { .. } => false,
         }
     }
 }
@@ -360,8 +374,10 @@ impl Args for Options {
                     reply_to = Some(rev);
                 }
 
-                // Review options.
-                Long("revision") if op == Some(OperationName::Review) => {
+                // Review/diff options.
+                Long("revision") | Short('r')
+                    if op == Some(OperationName::Review) || op == Some(OperationName::Diff) =>
+                {
                     let val = parser.value()?;
                     let rev = term::args::rev(&val)?;
 
@@ -511,6 +527,7 @@ impl Args for Options {
                     "y" | "ready" => op = Some(OperationName::Ready),
                     "e" | "edit" => op = Some(OperationName::Edit),
                     "r" | "redact" => op = Some(OperationName::Redact),
+                    "diff" => op = Some(OperationName::Diff),
                     "assign" => op = Some(OperationName::Assign),
                     "label" => op = Some(OperationName::Label),
                     "comment" => op = Some(OperationName::Comment),
@@ -526,6 +543,7 @@ impl Args for Options {
                     if patch_id.is_none()
                         && [
                             Some(OperationName::Show),
+                            Some(OperationName::Diff),
                             Some(OperationName::Update),
                             Some(OperationName::Delete),
                             Some(OperationName::Archive),
@@ -553,6 +571,10 @@ impl Args for Options {
                 patch_id: patch_id.ok_or_else(|| anyhow!("a patch must be provided"))?,
                 diff,
             },
+            OperationName::Diff => Operation::Diff {
+                patch_id: patch_id.ok_or_else(|| anyhow!("a patch must be provided"))?,
+                revision_id,
+            },
             OperationName::Delete => Operation::Delete {
                 patch_id: patch_id.ok_or_else(|| anyhow!("a patch must be provided"))?,
             },
@@ -652,6 +674,17 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
                 &workdir,
             )?;
         }
+        Operation::Diff {
+            patch_id,
+            revision_id,
+        } => {
+            let patch_id = patch_id.resolve(&repository.backend)?;
+            let revision_id = revision_id
+                .map(|rev| rev.resolve::<radicle::git::Oid>(&repository.backend))
+                .transpose()?
+                .map(patch::RevisionId::from);
+            diff::run(&patch_id, revision_id, &repository)?;
+        }
         Operation::Update {
             ref patch_id,
             ref base_id,
diff --git a/radicle-cli/src/commands/patch/diff.rs b/radicle-cli/src/commands/patch/diff.rs
new file mode 100644
index 00000000..a7030532
--- /dev/null
+++ b/radicle-cli/src/commands/patch/diff.rs
@@ -0,0 +1,36 @@
+use std::process;
+
+use radicle::cob::patch;
+use radicle::storage::git::Repository;
+
+use super::*;
+
+pub fn run(
+    patch_id: &PatchId,
+    revision_id: Option<patch::RevisionId>,
+    stored: &Repository,
+) -> anyhow::Result<()> {
+    let patches = patch::Patches::open(stored)?;
+    let Some(patch) = patches.get(patch_id)? else {
+        anyhow::bail!("Patch `{patch_id}` not found");
+    };
+    let revision = if let Some(r) = revision_id {
+        patch
+            .revision(&r)
+            .ok_or(anyhow!("revision `{r}` not found"))?
+    } else {
+        let (_, r) = patch.latest();
+        r
+    };
+    let (from, to) = revision.range();
+
+    process::Command::new("rad")
+        .current_dir(stored.path())
+        .args(["diff", from.to_string().as_str(), to.to_string().as_str()])
+        .stdout(process::Stdio::inherit())
+        .stderr(process::Stdio::inherit())
+        .spawn()?
+        .wait()?;
+
+    Ok(())
+}
diff --git a/radicle-cli/src/commands/patch/list.rs b/radicle-cli/src/commands/patch/list.rs
index b167ad4e..1765f1c2 100644
--- a/radicle-cli/src/commands/patch/list.rs
+++ b/radicle-cli/src/commands/patch/list.rs
@@ -100,7 +100,7 @@ pub fn row(
 ) -> anyhow::Result<[term::Line; 9]> {
     let state = patch.state();
     let (_, revision) = patch.latest();
-    let (from, to) = patch.range(repository)?;
+    let (from, to) = revision.range();
     let stats = common::diff_stats(repository.raw(), &from, &to)?;
     let author = patch.author().id;
     let (alias, did) = Author::new(&author, profile).labels();
diff --git a/radicle-cli/src/commands/patch/show.rs b/radicle-cli/src/commands/patch/show.rs
index b67c3cf3..33ab0854 100644
--- a/radicle-cli/src/commands/patch/show.rs
+++ b/radicle-cli/src/commands/patch/show.rs
@@ -13,7 +13,7 @@ use crate::terminal as term;
 use super::*;
 
 fn show_patch_diff(patch: &patch::Patch, stored: &Repository) -> anyhow::Result<()> {
-    let (from, to) = patch.range(stored)?;
+    let (from, to) = patch.range()?;
     let range = format!("{}..{}", from, to);
 
     process::Command::new("git")
@@ -28,7 +28,7 @@ fn show_patch_diff(patch: &patch::Patch, stored: &Repository) -> anyhow::Result<
 }
 
 fn patch_commits(patch: &patch::Patch, stored: &Repository) -> anyhow::Result<Vec<term::Line>> {
-    let (from, to) = patch.range(stored)?;
+    let (from, to) = patch.range()?;
     let range = format!("{}..{}", from, to);
 
     let mut revwalk = stored.revwalk(*patch.head())?;
diff --git a/radicle-cli/src/git/pretty_diff.rs b/radicle-cli/src/git/pretty_diff.rs
index b92ca2a9..aec270f1 100644
--- a/radicle-cli/src/git/pretty_diff.rs
+++ b/radicle-cli/src/git/pretty_diff.rs
@@ -13,8 +13,10 @@ use crate::terminal::highlight::{Highlighter, Theme};
 use super::unified_diff::{Decode, HunkHeader};
 
 /// Blob returned by the [`Repo`] trait.
+#[derive(PartialEq, Eq)]
 pub enum Blob {
     Binary,
+    Empty,
     Plain(Vec<u8>),
 }
 
@@ -33,7 +35,13 @@ impl Repo for git::raw::Repository {
         if blob.is_binary() {
             Ok(Blob::Binary)
         } else {
-            Ok(Blob::Plain(blob.content().to_vec()))
+            let content = blob.content();
+
+            if content.is_empty() {
+                Ok(Blob::Empty)
+            } else {
+                Ok(Blob::Plain(blob.content().to_vec()))
+            }
         }
     }
 
@@ -226,6 +234,14 @@ impl ToPretty for DiffContent {
 
         match context {
             FileDiff::Moved(_) | FileDiff::Copied(_) => {}
+            FileDiff::Added(_) if blobs.new.is_none() => {
+                vstack = vstack.divider();
+                vstack.push(term::Line::new(term::format::italic("Empty file")));
+            }
+            FileDiff::Deleted(_) if blobs.old.is_none() => {
+                vstack = vstack.divider();
+                vstack.push(term::Line::new(term::format::italic("Empty file")));
+            }
             FileDiff::Added(_) | FileDiff::Deleted(_) | FileDiff::Modified(_) => {
                 vstack = vstack.divider();
 
diff --git a/radicle-cli/tests/commands.rs b/radicle-cli/tests/commands.rs
index 554c4880..ff515823 100644
--- a/radicle-cli/tests/commands.rs
+++ b/radicle-cli/tests/commands.rs
@@ -464,6 +464,20 @@ fn rad_patch() {
     test("examples/rad-patch.md", working.path(), Some(home), []).unwrap();
 }
 
+#[test]
+fn rad_patch_diff() {
+    let mut environment = Environment::new();
+    let profile = environment.profile(config::profile("alice"));
+    let working = tempfile::tempdir().unwrap();
+    let home = &profile.home;
+
+    // Setup a test repository.
+    fixtures::repository(working.path());
+
+    test("examples/rad-init.md", working.path(), Some(home), []).unwrap();
+    test("examples/rad-patch-diff.md", working.path(), Some(home), []).unwrap();
+}
+
 #[test]
 fn rad_patch_checkout() {
     let mut environment = Environment::new();
diff --git a/radicle/src/cob/patch.rs b/radicle/src/cob/patch.rs
index 6506b654..4da82886 100644
--- a/radicle/src/cob/patch.rs
+++ b/radicle/src/cob/patch.rs
@@ -99,7 +99,7 @@ pub enum Error {
     #[error("identity doc failed to load: {0}")]
     Doc(#[from] DocError),
     /// Identity document is missing.
-    #[error("missing identity docuemnt")]
+    #[error("missing identity document")]
     MissingIdentity,
     /// Error loading the document payload.
     #[error("payload failed to load: {0}")]
@@ -118,6 +118,9 @@ pub enum Error {
     /// An illegal action.
     #[error("action is not allowed: {0}")]
     NotAllowed(EntryId),
+    /// Revision not found.
+    #[error("revision not found: {0}")]
+    RevisionNotFound(RevisionId),
     /// Initialization failed.
     #[error("initialization failed: {0}")]
     Init(&'static str),
@@ -521,15 +524,8 @@ impl Patch {
     }
 
     /// Get the commit range of this patch.
-    pub fn range<R: ReadRepository>(
-        &self,
-        repo: &R,
-    ) -> Result<(git::Oid, git::Oid), git::ext::Error> {
-        if self.is_merged() {
-            Ok((*self.base(), *self.head()))
-        } else {
-            Ok((self.merge_base(repo)?, *self.head()))
-        }
+    pub fn range(&self) -> Result<(git::Oid, git::Oid), git::ext::Error> {
+        return Ok((*self.base(), *self.head()));
     }
 
     /// Index of latest revision in the revisions list.
@@ -1331,6 +1327,11 @@ impl Revision {
         self.oid
     }
 
+    /// Get the commit range of this revision.
+    pub fn range(&self) -> (git::Oid, git::Oid) {
+        (self.base, self.oid)
+    }
+
     /// When this revision was created.
     pub fn timestamp(&self) -> Timestamp {
         self.timestamp