From 732e3d9055db756be4d5d2670b88918efc184577 Mon Sep 17 00:00:00 2001
From: Yousef Moazzam <yousef.moazzam@diamond.ac.uk>
Date: Fri, 4 Sep 2026 15:53:20 +0100
Subject: [PATCH 1/4] Add minimal handling if account is null

---
 frontend/unified/src/App.tsx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/frontend/unified/src/App.tsx b/frontend/unified/src/App.tsx
index ad36268..0647e11 100644
--- a/frontend/unified/src/App.tsx
+++ b/frontend/unified/src/App.tsx
@@ -93,9 +93,12 @@ export const App: React.FC = () => {
   if (data === undefined) {
     return <p>Data undefined</p>;
   }
+  if (data.account === null) {
+    return <p>Account null</p>;
+  }
 
   const instrumentSession =
-    data.account?.instrumentSessionRoles.edges[0].node.instrumentSession;
+    data.account.instrumentSessionRoles.edges[0].node.instrumentSession;
 
   const handleChangeTechnique = (
     /**

From ba2183395bbeb8bb0cac3d89d1b1d86d81958bda Mon Sep 17 00:00:00 2001
From: Yousef Moazzam <yousef.moazzam@diamond.ac.uk>
Date: Fri, 4 Sep 2026 15:54:18 +0100
Subject: [PATCH 2/4] Use instrument session type from query response type

---
 .../src/components/SessionSelector.tsx        | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/frontend/unified/src/components/SessionSelector.tsx b/frontend/unified/src/components/SessionSelector.tsx
index ca1b689..de1fe39 100644
--- a/frontend/unified/src/components/SessionSelector.tsx
+++ b/frontend/unified/src/components/SessionSelector.tsx
@@ -14,23 +14,10 @@ enum SessionSelectionMode {
   Custom = "Custom",
 }
 
-type Proposal = {
-  proposalNumber: number;
-  proposalCategory: string;
-};
-
-type Instrument = {
-  name: string;
-};
-
-export type InstrumentSession = {
-  instrumentSessionNumber: number;
-  proposal: Proposal;
-  instrument: Instrument;
-};
-
 type SessionSelectorProps = {
-  session: InstrumentSession;
+  session: NonNullable<
+    SessionQueryQuery["account"]
+  >["instrumentSessionRoles"]["edges"][0]["node"]["instrumentSession"];
 };
 
 export const SessionSelector: React.FC<SessionSelectorProps> = ({

From d022d22569b0e3e9490f343bcdb5e433d071e373 Mon Sep 17 00:00:00 2001
From: Yousef Moazzam <yousef.moazzam@diamond.ac.uk>
Date: Fri, 4 Sep 2026 15:56:55 +0100
Subject: [PATCH 3/4] Remove unnecessary uses of question mark operator

---
 frontend/unified/src/App.tsx                        | 6 +++---
 frontend/unified/src/components/SessionSelector.tsx | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/frontend/unified/src/App.tsx b/frontend/unified/src/App.tsx
index 0647e11..251b74e 100644
--- a/frontend/unified/src/App.tsx
+++ b/frontend/unified/src/App.tsx
@@ -203,9 +203,9 @@ export const App: React.FC = () => {
                 // a capitalised "proposal code", whereas the workflows service only accepts
                 // it in lowercase
                 proposalCode:
-                  instrumentSession?.proposal.proposalCategory.toLowerCase(),
-                proposalNumber: instrumentSession?.proposal.proposalNumber,
-                number: instrumentSession?.instrumentSessionNumber,
+                  instrumentSession.proposal.proposalCategory.toLowerCase(),
+                proposalNumber: instrumentSession.proposal.proposalNumber,
+                number: instrumentSession.instrumentSessionNumber,
               }}
             />
           </Stack>
diff --git a/frontend/unified/src/components/SessionSelector.tsx b/frontend/unified/src/components/SessionSelector.tsx
index de1fe39..848f4f9 100644
--- a/frontend/unified/src/components/SessionSelector.tsx
+++ b/frontend/unified/src/components/SessionSelector.tsx
@@ -29,7 +29,7 @@ export const SessionSelector: React.FC<SessionSelectorProps> = ({
   const [textInputValue, setTextInputValue] = useState<string>("");
 
   const proposal = session?.proposal;
-  const latestSession = `${proposal?.proposalCategory?.toLowerCase()}${proposal?.proposalNumber}-${session?.instrumentSessionNumber}`;
+  const latestSession = `${proposal.proposalCategory?.toLowerCase()}${proposal.proposalNumber}-${session.instrumentSessionNumber}`;
 
   return (
     <Stack direction="row" spacing={2} alignItems={"center"}>

From f8cee5996284de681dd728fd5b8978ff7349624b Mon Sep 17 00:00:00 2001
From: Yousef Moazzam <yousef.moazzam@diamond.ac.uk>
Date: Fri, 4 Sep 2026 16:03:01 +0100
Subject: [PATCH 4/4] Add helper type for non-null account

---
 frontend/unified/src/components/SessionSelector.tsx | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/frontend/unified/src/components/SessionSelector.tsx b/frontend/unified/src/components/SessionSelector.tsx
index 848f4f9..d3e8be3 100644
--- a/frontend/unified/src/components/SessionSelector.tsx
+++ b/frontend/unified/src/components/SessionSelector.tsx
@@ -14,10 +14,10 @@ enum SessionSelectionMode {
   Custom = "Custom",
 }
 
+type NonNullAccount = NonNullable<SessionQueryQuery["account"]>;
+
 type SessionSelectorProps = {
-  session: NonNullable<
-    SessionQueryQuery["account"]
-  >["instrumentSessionRoles"]["edges"][0]["node"]["instrumentSession"];
+  session: NonNullAccount["instrumentSessionRoles"]["edges"][0]["node"]["instrumentSession"];
 };
 
 export const SessionSelector: React.FC<SessionSelectorProps> = ({