web aliasing of accounting and others

web/src/pages/add_table/state.rs

@@ -231,7 +231,15 @@ impl AddTablePageState {
             // backend names and remain the exception.
             let aliasable = column.data_type != ACCOUNTING_TRANSFER_FIELD_TYPE;
 
-            for generated in columns.generated_columns_of(index) {
+            let generated_columns = columns.generated_columns_of(index);
+            // Whether the backend already reports `account` as one of them, in
+            // which case the foreign-key row below is a second view of a column
+            // that is named once, not a column of its own to name again.
+            let account_reported = generated_columns
+                .iter()
+                .any(|generated| generated.name == ACCOUNT_API_COLUMN);
+
+            for generated in generated_columns {
                 let mut tags = vec![format!("generated by {}", column.data_type)];
                 if generated.inherits_currency {
                     tags.push(format!("{}, {}", column.currency, column.money_mode.label()));
@@ -250,9 +258,10 @@ impl AddTablePageState {
                 });
             }
 
-            // The account foreign key is a system column rather than a
-            // generated user column, so the catalog does not report it; the
-            // same explanation as in `TableDraft::preview_rows`.
+            // The physical column the account foreign key is stored in. It is
+            // a system column, so it is listed whether or not the catalog
+            // reports `account` among the generated ones — but it is named
+            // there when it does, never twice.
             if column.data_type == ACCOUNTING_FIELD_TYPE {
                 rows.push(ColumnRow {
                     index: None,
@@ -269,7 +278,7 @@ impl AddTablePageState {
                             self.draft.generated_display_name(ACCOUNT_API_COLUMN)
                         ),
                     ],
-                    alias_source: Some(ACCOUNT_API_COLUMN.to_string()),
+                    alias_source: (!account_reported).then(|| ACCOUNT_API_COLUMN.to_string()),
                     alias: self.draft.alias_for(ACCOUNT_API_COLUMN).to_string(),
                 });
             }
@@ -277,6 +286,33 @@ impl AddTablePageState {
         rows
     }
 
+    /// The generated columns that may be renamed, in the order they are
+    /// listed.
+    ///
+    /// Renaming lives in a section of its own rather than in the column list:
+    /// the list is where the table is read, and a text box in every other row
+    /// of it turns reading into scanning past inputs.
+    /// One field per generated column and no more: a source named twice would
+    /// be two fields over one column, and the draft reads the first of them,
+    /// so whatever was typed in the second would be dropped without a word.
+    pub(crate) fn alias_rows(&self) -> Vec<AliasRow> {
+        let mut rows: Vec<AliasRow> = Vec::new();
+        for row in self.column_rows() {
+            let Some(source) = row.alias_source else {
+                continue;
+            };
+            if rows.iter().any(|existing| existing.source == source) {
+                continue;
+            }
+            rows.push(AliasRow {
+                source,
+                alias: row.alias,
+                data_type: row.data_type,
+            });
+        }
+        rows
+    }
+
     /// Row-display candidates: `id` first, then every column, matching the
     /// client's candidate list.
     pub(crate) fn row_display_candidates(&self) -> Vec<RowDisplayCandidate> {
@@ -331,6 +367,16 @@ pub(crate) struct ColumnRow {
     pub alias: String,
 }
 
+/// One line of the "Rename generated columns" section: a generated column the
+/// request may name, and the name asked for it so far.
+pub(crate) struct AliasRow {
+    /// The generated column's own name, which is what the rename asks for.
+    pub source: String,
+    /// The alias typed for it, empty when the backend's name is being kept.
+    pub alias: String,
+    pub data_type: String,
+}
+
 pub(crate) struct RowDisplayCandidate {
     pub index: usize,
     pub name: String,
@@ -449,6 +495,7 @@ mod tests {
                 "tax_point_date",
                 "debit",
                 "credit",
+                "account",
                 "account_id",
             ]
         );
@@ -504,7 +551,11 @@ mod tests {
         let row = |name: &str| rows.iter().find(|row| row.name == name).unwrap();
         assert_eq!(row("debit").alias_source.as_deref(), Some("debit"));
         assert_eq!(row("debit").alias, "md");
-        assert_eq!(row("account_id").alias_source.as_deref(), Some("account"));
+        // `account` is reported by the catalog, so it is named there and the
+        // physical column it lands in is not offered a second field.
+        assert_eq!(row("account").alias_source.as_deref(), Some("account"));
+        assert_eq!(row("account").alias, "ucet");
+        assert!(row("account_id").alias_source.is_none());
         assert!(row("account_id").tags.contains(&"written as ucet".to_string()));
         assert!(
             row("accounting").alias_source.is_none(),