Compile: use latexmk (-xelatex -f) first; accept PDF even if return code non-zero

app.py

@@ -429,18 +429,18 @@ def _compile_poster_pdf(OUTPUT_DIR: Path, logs):
         def _has(bin_name):
             return _sh.which(bin_name) is not None
 
-        # Prefer XeLaTeX (Overleaf-like), then LuaLaTeX, then latexmk (forced XeLaTeX)
-        if _has("xelatex"):
+        # Most-tolerant: prefer latexmk with XeLaTeX and force (-f), then XeLaTeX, then LuaLaTeX
+        if _has("latexmk"):
+            cmd = ["latexmk", "-xelatex", "-pdf", "-f", "-interaction=nonstopmode", "-file-line-error", tex_path.name]
+            logs.append("▶ Compiling with latexmk (-xelatex, -f) …")
+        elif _has("xelatex"):
             cmd = ["xelatex", "-interaction=nonstopmode", "-file-line-error", tex_path.name]
             logs.append("▶ Compiling with xelatex …")
         elif _has("lualatex"):
             cmd = ["lualatex", "-interaction=nonstopmode", "-file-line-error", tex_path.name]
             logs.append("▶ Compiling with lualatex …")
-        elif _has("latexmk"):
-            cmd = ["latexmk", "-xelatex", "-pdf", "-interaction=nonstopmode", tex_path.name]
-            logs.append("▶ Compiling with latexmk (-xelatex) …")
         else:
-            logs.append("⚠️ No TeX engine found (xelatex/lualatex/latexmk). Skipping PDF compile.")
+            logs.append("⚠️ No TeX engine found (latexmk/xelatex/lualatex). Skipping PDF compile.")
             return None
 
         import os as _os
@@ -455,17 +455,21 @@ def _compile_poster_pdf(OUTPUT_DIR: Path, logs):
         proc = _sp.run(cmd, cwd=str(proj_dir), stdout=_sp.PIPE, stderr=_sp.STDOUT, text=True, env=_env)
         if proc.stdout:
             logs.append(proc.stdout[-4000:])
-        if proc.returncode != 0:
-            logs.append(f"❌ PDF compile failed with code {proc.returncode}.")
-            return None
 
-        # Find produced PDF
+        # Accept PDF even if return code is non-zero (be tolerant)
         for out_name in ("poster_output.pdf", "poster.pdf", tex_path.stem + ".pdf"):
             out_path = proj_dir / out_name
             if out_path.exists():
-                logs.append(f"✅ PDF generated → {out_path.relative_to(OUTPUT_DIR)}")
+                if proc.returncode != 0:
+                    logs.append(f"⚠️ Compile returned code {proc.returncode}, but PDF exists; using it.")
+                else:
+                    logs.append(f"✅ PDF generated → {out_path.relative_to(OUTPUT_DIR)}")
                 return out_path
 
+        if proc.returncode != 0:
+            logs.append(f"❌ PDF compile failed with code {proc.returncode} and no PDF produced.")
+            return None
+
         logs.append("⚠️ PDF not found after compile.")
         return None
     except Exception as e:
@@ -516,10 +520,14 @@ def _compile_tex_to_pdf(tex_path: Path, logs):
         proc = _sp.run(cmd, cwd=str(proj_dir), stdout=_sp.PIPE, stderr=_sp.STDOUT, text=True, env=_env)
         if proc.stdout:
             logs.append(proc.stdout[-4000:])
+        guess = proj_dir / (tex_path.stem + ".pdf")
         if proc.returncode != 0:
-            logs.append(f"❌ PDF compile failed with code {proc.returncode}.")
+            # Be tolerant: if a PDF was produced despite errors, use it.
+            if guess.exists():
+                logs.append(f"⚠️ Compile returned code {proc.returncode}, but PDF exists; using it.")
+                return guess
+            logs.append(f"❌ PDF compile failed with code {proc.returncode} and no PDF produced.")
             return None
-        guess = proj_dir / (tex_path.stem + ".pdf")
         return guess if guess.exists() else None
     except Exception as e:
         logs.append(f"⚠️ PDF compile error: {e}")