cli: make large file snapshot error more readable

When the difference is within epsilon, output the raw bytes so that the user can easily see it; otherwise use human readable bytes, as the exact size isn't too important. Signed-off-by: Austin Seipp <[email protected]> Change-Id: Id67394bf9eacfd05f934a2bd420f2265ad77a298
jj-vcs · Apr 18, 2024 · db42b54 · db42b54
1 parent 7bcfab6
commit db42b54
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Showing 2 changed files with 38 additions and 19 deletions.
diff --git a/cli/src/command_error.rs b/cli/src/command_error.rs
@@ -300,23 +300,44 @@ impl From<SnapshotError> for CommandError {
                 path,
                 size,
                 max_size,
-            } => user_error(format!(
-                "Failed to snapshot the working copy\nThe file '{}' is too large to be \
-                 snapshotted ({} bytes).\nThe maximum size allowed is {} bytes.",
-                path.display(),
-                size.0,
-                max_size.0
-            ))
-            .hinted(format!(
-                "This is to prevent large files from being added on accident. You can fix this \
-                 error by:
+            } => {
+                // if the size difference is < 1KiB, then show exact bytes.
+                // otherwise, show in human-readable form; this avoids weird cases
+                // where a file is 400 bytes too large but the error says something
+                // like '1.0MiB, maximum size allowed is ~1.0MiB'
+                let size_diff = size.0 - max_size.0;
+                let err_str = if size_diff <= 1024 {
+                    format!(
+                        "it is {} bytes too large; the maximum size allowed is {} bytes ({}).",
+                        size_diff,
+                        max_size.0,
+                        max_size.to_string()
+                    )
+                } else {
+                    format!(
+                        "it is {}; the maximum size allowed is ~{}.",
+                        size.to_string(),
+                        max_size.to_string()
+                    )
+                };
+
+                user_error(format!(
+                    "Failed to snapshot the working copy\nThe file '{}' is too large to be \
+                     snapshotted: {}",
+                    path.display(),
+                    err_str,
+                ))
+                .hinted(format!(
+                    "This is to prevent large files from being added on accident. You can fix \
+                     this error by:
   - Adding the file to `.gitignore`
   - Run `jj config set --repo snapshot.max-new-file-size \"{}B\"`
     This will increase the maximum file size allowed for new files, in this repository only.
   - Run `jj --config-toml 'snapshot.max-new-file-size=\"{}B\"' st`
     This will increase the maximum file size allowed for new files, for this command only.",
-                size.0, size.0
-            )),
+                    size.0, size.0
+                ))
+            }
             err => internal_error_with_message("Failed to snapshot the working copy", err),
         }
     }

diff --git a/cli/tests/test_working_copy.rs b/cli/tests/test_working_copy.rs
@@ -27,8 +27,7 @@ fn test_snapshot_large_file() {
     let stderr = test_env.jj_cmd_failure(&repo_path, &["files"]);
     insta::assert_snapshot!(stderr, @r###"
     Error: Failed to snapshot the working copy
-    The file '$TEST_ENV/repo/large' is too large to be snapshotted (13 bytes).
-    The maximum size allowed is 10 bytes.
+    The file '$TEST_ENV/repo/large' is too large to be snapshotted: it is 3 bytes too large; the maximum size allowed is 10 bytes (10.0B).
     Hint: This is to prevent large files from being added on accident. You can fix this error by:
       - Adding the file to `.gitignore`
       - Run `jj config set --repo snapshot.max-new-file-size "13B"`
@@ -39,18 +38,17 @@ fn test_snapshot_large_file() {
 
     // test with a larger file using 'KB' human-readable syntax
     test_env.add_config(r#"snapshot.max-new-file-size = "10KB""#);
-    let big_string = vec![0; 1024 * 11];
+    let big_string = vec![0; 1024 * 12];
     std::fs::write(repo_path.join("large"), big_string).unwrap();
     let stderr = test_env.jj_cmd_failure(&repo_path, &["files"]);
     insta::assert_snapshot!(stderr, @r###"
     Error: Failed to snapshot the working copy
-    The file '$TEST_ENV/repo/large' is too large to be snapshotted (11264 bytes).
-    The maximum size allowed is 10240 bytes.
+    The file '$TEST_ENV/repo/large' is too large to be snapshotted: it is 12.0KiB; the maximum size allowed is ~10.0KiB.
     Hint: This is to prevent large files from being added on accident. You can fix this error by:
       - Adding the file to `.gitignore`
-      - Run `jj config set --repo snapshot.max-new-file-size "11264B"`
+      - Run `jj config set --repo snapshot.max-new-file-size "12288B"`
         This will increase the maximum file size allowed for new files, in this repository only.
-      - Run `jj --config-toml 'snapshot.max-new-file-size="11264B"' st`
+      - Run `jj --config-toml 'snapshot.max-new-file-size="12288B"' st`
         This will increase the maximum file size allowed for new files, for this command only.
     "###);
 }